Abundant life: The diversity of life in the biosphere

by

David C. Bossard

IBRI Fellow

 

 

 

 

Abstract

Abundant Life

 

The amazing diversity of life began to show up in the fossil record during the “Cambrian Explosion”, a brief period of intense creative activity about 550 to 600 million years ago. It took place as soon as the earth was able to support complex, multi-cellular life. This talk takes up the creation story at that point and considers some of the complex innovations that occurred then and during the subsequent creation of land-based plants and animals, innovations that are so focussed that they reveal purposeful creative activity by God. The great diversity of life in God’s creation suggests a Principle of Plentitude (recently noted by Michael Denton) to guide his creative work. The talk includes a number of examples to illustrate this principle.

 

 

 

 

 


Abundant life: The diversity of life in the biosphere

 

O wonder! How many goodly creatures are there heere!

---William Shakespeare,

The Tempest, Act V Scene 1

 

[Slide 1] We have a lot to cover today. I hope you don’t leave here totally bewildered, even though there may be some things you don’t fully understand. I don’t fully understand everything we will touch on tonight. There are some times that I feel as if I am at the opening of a great door of understanding, a door that is only yet open a crack, but even the view through that small opening hints at wonderful things yet to be seen and understood.

 

There are lots and lots of things that we don’t yet know about how God went about his creative work, but God has designed the natural world in such a way that his work leaves traces that can be revealed by hard, honest, scientific study. He did not have to do this, and we should give him praise and thanks for this revealing design. We will see some remarkable examples later in the talk.

 

         Despite the amazing advances of science in the past few decades, and they are truly amazing, there still are far more things that we don’t know than that we do know. In the course of preparing this talk I read a great work by Ernst Haeckel, written in the 1880’s.[1] As I read it, and noted how he sometimes passed over details that would in later years be seen as important, and so was led in some false directions, I was reminded that where we are today may likewise be seen as incomplete and primitive a hundred years from now. I know that some Creationists focus on Haeckel’s errors, but I see him as a great scientist in the true sense of the word. He was a pioneer charting out a great new wilderness, and did his scientific work honestly, and with great skill, as far as his available tools would allow.

 

         In our remarks about the creation of plants and animals, as Haeckel did, I may be tempted to make a few speculative comments. I hope you will not hold it against me if I turn out to be wrong in a thing or two. That is the nature of science, after all.

 

[Slide 2] There is a question—I call it the nonsense question—that hangs around in the back of my mind. The question is this: “What are the limits to natural development?” I call it “nonsense” in quotes, because a scientist who believes that everything we see today came about by random undirected processes, will say, probably with a dismissing air of superiority, that there are no limits to natural development, other than limits that are posed by physical and chemical considerations -- for example, you can’t have humans 20 feet tall for good physical reasons having to do with the ability to support and supply such a body.

 

         But for me, as one who believes in God’s direct creative activity, but at the same time understands that there is a lot of natural change that constantly occurs within species lines, the question is a very real one: I want to know where in the creation of life, God allowed natural processes to rule, and where he had to step in. I believe that he did have to step in, because I believe that there are certain developments that are so complex, and require such a careful orchestration of events, that natural processes left to themselves would never come up with the necessary results—unless, of course, you credit nature with God-like qualities. An example is the original creation of bacterial life nearly 4 billion years ago, a subject discussed in my last talk.[2]

 

         So the question is very intriguing to me: What ARE the limits of natural development? When God ordered his creatures to reproduce ‘after their kind’, what are the limits of ‘kind’? Could a single kind produce lions, tigers and kitties? That is, by legitimately producing “after its kind” by natural processes? Suppose within this group some remarkable biological innovations are found? How about hippos and horses? Or cows and camels?

 

         Just to look ahead a bit, I think that an answer to this nonsense question will have some real surprises. The reason is simple: the issue of “kind” is a genetic one, buried in the genes, but the only way that we have been able to study kinds in the past has been by looking at the physical appearance, the morphology to use a technical term—that was one of the limitations that Haeckel faced a century ago, since he worked long before the modern discoveries in genetics. We have all experienced times when two things look alike but are entirely unrelated, and we have experienced the converse, too. Perhaps when we understand the genetics more fully we will have to rearrange our notions of relatedness—both creationists and secular scientists.

 

         But enough of that! So that you will be able to get a sense of where we are heading, here is an outline of the talk. We will first talk about the Cambrian explosion which is the first time that animals show up in the fossil record, about 550 to 600 million years ago (the date is in flux, but the trend is backwards). Next we will give a quick overview of when fossil land plants and animals show up. Then we will return to the nonsense question, using the example of radiolarians and trilobites to fuel the discussion—both have a very long fossil history. Finally we will wrap up with some conclusions and a mention of Michael Denton’s conjecture about Abundant Life, which inspired the title of this talk.

 

         In this talk I won’t say much about how we determine the age of fossils. There are numerous independent and overlapping ways to date fossils and geologic formations. They tell a consistent story, and I see no reason to dispute them. If this makes you unhappy, I am sorry, but that is another talk. In the last talk I discussed radioactive dating, but this is only one of many ways to date rocks and fossils. Some methods can even measure the lengths of solar years and lunar months, with the result that it is known that in the Cambrian age there were about 415 days in a year (the earth rotated faster then) and a lunar month was about 31.5 days long (the moon was closer then).

 

The Cambrian Explosion.

 

         In the last talk, A Fit Place for Life, we discussed the preparation of the environment for the arrival of plants and animals. This preparation took about 3 billion years, bringing earth’s history to about 600 million years (My) ago, where this talk picks up. The preparation included an oxygen atmosphere and a broad distribution of available nitrogen and other organic food that is needed by all advanced life. The only missing piece in this preparation is protection of dry land from solar and cosmic radiation. This is done by the ozone layer, which was slowly being built up but would not be fully in place for another 300 My.

 

         In the last talk, we noted two clear instances of God’s direct creative activity: first, in the initial creation of bacterial life sometime shortly before 3600 My ago; and second, in the creation of vastly more complex eukaryotic life about 1800 My ago, that is, single-celled creatures that have a nucleus along with other complex structural parts—think amoebas and the slipper-shaped paramecium, for example.

 

         At the point where we begin today, marine life is possible after the long build-up of the needed nutrients, but only bacteria can survive on dry land. Starting about 1000 My ago, bacteria are at their task of spreading nutrients on dry land for the future arrival of plants and animals. Complex life on dry land is still impossible because of radiation from the sun and outer space. Bacteria can survive on land because they reproduce rapidly and their genetic make-up is less vulnerable to random destruction of the genetic information—and, indeed, damaged bacteria also contribute food to the survivors.

 

[Slide 3] The Animal kingdom appears suddenly in the fossil record shortly after 600 My ago, in what has come to be called the Cambrian explosion. The boundary that defines the start of the Cambrian age is the appearance of fossil burrows that were obviously made by a complex animal, probably an arthropod—the name means “jointed feet”, think lobster. We will meet trilobites, a kind of arthropod, in a minute.

 

Trichophycus fossil burrows of the type

that define the start of the Cambrian age[3]

 

The beginning of the Cambrian age is currently set at about 590 My ago, and marks the start of the “Phanerozoic Era”, which means “visible animals”, ones that are visible to the unaided eye.[4]

 

[Slide 4] One of the earliest actual animal fossils is the trilobite, an arthropod that appears suddenly in the fossil record about 570 My ago.

 

Early trilobite (early Cambrian)

Lena River Gorge, Siberia

Bergeroniellus spinosus[5]

 

[Slide 5] To give a flavor of what I mean by suddenly, here is a quote from one author:

 

“Fossils of trilobites appeared suddenly in the geological record …. If you are tempted by the word “dramatic” then this is the occasion where you could be forgiven for weakening. When you visit a rock section spanning the right bit of the early Cambrian—and there are such profiles in Newfoundland, Mongolia and Siberia—there will be not a sniff of a trilobite as you work your way upwards from one bed to its successor…Then, quite suddenly, a whole Profallotaspis or an Olenellus as big as a crab will pop out into your waiting hands as you split the rock. These are trilobites with lots of segments and big eyes: striking things, not little squitty objects.…You are tempted to cry out: ‘bang!’ And as you continue to collect a foot or so higher into younger strata, the first trilobite will be joined by others, maybe half a dozen or so different species, and all individually distinctive ones at that.”

Richard Fortey, Trilobite![6]

 

[Slide 6] The Cambrian age is the first appearance of animals. To this point we have been talking about plants and animals as if the meanings of the terms were obvious. But even biologists still argue about the precise meaning of the words. I would like to use a definition that will suit our purposes although it may not satisfy everyone.

 

         For our purposes all plants—Kingdom Plantae— and animals—Kingdom Animalia— have many cells, reproduce sexually with sperm and egg, and develop from embryos. This definition eliminates all bacteria and single-celled creatures, and fungi which make up the Kingdoms of Bacteria, Protoctista and Fungi (Hence the title of Lynn Margulis’ book Five Kingdoms). You can immediately guess that the arrival of plants and animals was a phenomenal jump in complexity, easily comparable to the jump that occurred with the creation of the first cell with a nucleus.

 

         An outstanding feature that distinguishes animals from plants is in the basic way that the embryos develop. All living cells have to have a way to turn particular genes on and off. This is done with proteins that are produced by a group of genes called the homeobox genes. Animals have in addition to this other genes called the homeotic genes. These are the genes that orient the body so that development proceeds differently in different parts of the body, even in different parts of an individual cell, particularly in the early stages of the embryo. Genes that are both homeobox and homeotic are called Hox genes. Animals have Hox genes: they turn genes on and off and also distinguish different regions of gene development. The Hox genes are responsible for the visible complexity and symmetry expressed in animals.[7]

 

         So in animals there is a genetic body plan that distinguishes, in the general case, front/back, top/bottom and left/right. One of the crazy types of experimentation done today is to mix this up, and re-arrange where the various hox genes get expressed. The result is legs where antennas should be, eyes in armpits, and so on.

 

         You can immediately guess that the emergence of animal body plans represents a further phenomenal jump in complexity. Consider each of the great unifying themes of plants and animals:

 

         the invention of sex – specifically, a new way of cell division called meiosis to complement mitosis, which is the way bacteria and single-celled eukariotes divide;

 

         The embryo and embryonic development, and the creation of the apparatus involved in forming body plans; and

 

         • The creation of structural and functional systems: roots, stems, leaves and vascular systems for plants, and for animals the sensory, nervous, digestive, muscular and other systems.

 

         All told, these require such a remarkable level of innovation that it is impossible for me to even begin to imagine a random undirected way that such innovation could come about. The complex orchestration to achieve these innovations is beyond description. But we must move on.

 

[Slide 7] Lynn Margulis divides the Animal Kingdom into 37 phyla, labeled A-1 to A-37. The phyla are the various body plans, and every one of them, with a possible quibble about A-37, suddenly appeared in the Cambrian explosion. About half of the phyla are worms of some sort, which are, I suppose, of great interest to biologists. 

 

         Here are the phyla that are familiar to most of us and that are found among the Cambrian fossils:


 

 

Common Animal Phyla Originating in Cambrian Explosion[8]

designation

Name

Name Meaning

Examples

A-2

Porifera

porous, spongy

sponges

A-3

Cnidaria

nettle (stinging)

corals, hydras, medusas

A-13

Rotifera

wheel (beating cilia appear rotating)

“wheel animacules”

A-19

Chelicerata

class Arachnida

claw (Arachnida = goddess Arachne)

scorpions

spiders

A-20

Mandibulata

chewing jaw

termites, insects

A-21

Crustacea

shelly, crusty

lobsters, crabs

A-22

Annelida

ring (segments)

earthworms

A-26

Mollusca

soft body

clams, octopus

A-30

Brachiopoda

“arm leg” tentacles

lampshells

A-34

Echinodermata

sea urchin skin

starfish

A-37

Craniata

(all modern species are vertebrates)

brain

fish, amphibians,

reptiles, birds,

mammals

Note: A-19 to A-21 are the Arthropods = “joint-footed”

 

         All of these animal phyla appear suddenly, and for the first time, in the Cambrian explosion. Some claim that they all show up within a period of 5 million years, about 545 My ago. I don’t quite agree that the evidence shows this since we keep finding earlier and earlier examples of animal fossils (such as the early trilobites already mentioned). But it seems pretty clear that the animal kingdom for practical purposes, showed up in one geological instant.

 

[Slide 8] Here is a collage of some of the Cambrian animals and fossils from the Burgess Shale Formation in Canada, originally published in Scientific American. The Burgess Shale is dated to mid-Cambrian, about 445 My ago, and until recently was one of the most intensively studied sites from the Cambrian era. I think though, that more active current interest is being directed to sites at Chengjiang in China, and sites in Mongolia and Greenland which are some 30 My earlier, around 575 My ago. On the internet you can find illustrated catalogs of Cambrian fossils for sale—very high priced in my opinion—especially from the China site.

 

         The quibble I mentioned is about Pikaia, a possible example of A-37, Craniata, which appears to have segmented vertebra, but no clear evidence of a brain as such. Personally I am inclined to place the first appearance of Craniata a bit later.

 

The Burgess Shale Fossils in the Mid-Cambrian (about 545 My)[9]

 

         If you follow the usual arguments of natural Evolution you might think that the various phyla would appear in the fossil record in roughly the order of complexity of the body plan. You might expect, for example, that sponges which have no definite digestive gut and corals or hydras, which have a relatively simple blind gut would show up before animals that have a fully developed digestive system. But that is not the case; in fact the trilobites which have essentially all of the vital systems -- nerves, sensors, circulation, muscular, and a full digestive system, are among the earliest to appear in the fossil record. Trilobites show up suddenly, without any obvious predecessor among the logical body plans that one might expect to preceed them.

 

         In fact there is no clear order of first appearance in the geological record, certainly not any order that could be used to imply that one body plan is the ancestor of another. To a certain extent the accidental nature of fossil discoveries might explain away some mixing of first arrivals, but it is hard to explain away the total lack of order.

 

[Slide 9] Not only do the phyla show up in no clear order, but they show up with the most complex imaginable body plans. Here is an electron micrograph of a Cambrian bivalve crustacean — “bivalve” means it has two differently-shaped shells — folded up under its protective shells. Many details can be identified including legs, claws, and gills. Shortly we will see even more extensive detail in trilobite fossils. These elaborate animals show up suddenly, with no fossil predecessors.

 

Scanning Electron Micrograph

of an Early Cambrian bivalve Crustacean fossil[10]

 

         It is probably unnecessary to note that the first animals had only bacteria and minute organic wastes for food. Even the largest and most imposing of these animals, the trilobites, only ate such food. At first, they probably had no natural enemies. So have you noticed a curious thing? Both the trilobite shown earlier and the crustacean shown here have significant protective armor surrounding the soft body parts. And this is at a time when there were no predators. Clearly the body plan anticipates the future need for protection. Isn’t that curious! It doesn’t seem to follow the dictates of natural evolution. Why have armor if there are no predators? Predators come later. Particularly if the armor itself has some liabilities (such as restrictions on growth). When predators do show up, the armor may have some useful function. It would seem that these animals anticipated a need that was not present when they first appeared. We will see another striking example of anticipation later in this talk.

 

Moving to Land.

 

[Slide 10, left] The Cambrian is the first of a series of geological ages which record the creation of plants and animals and the migration of life from the sea to dry land. Here the ages are listed with the present at the top, and the Cambrian at the bottom.

 

         The geological ages are distinguished by the types of fossils found. The boundaries between ages are marked by various global events. The two most dramatic boundary events were mass extinctions: the Permian extinction about 250 My ago and the Cretaceous or K-T Extinction about 65 My ago. You know the K-T extinction as the time that dinosaurs were wiped out. This extinction occurred when a huge meteorite hit the earth in the vicinity of the Yucatan Penninsula at the Western boundary of the Gulf of Mexico. It is less certain what caused the Permian extinction, possibly another meteorite impact or possibly earth cooling in a massive ice age.

 

         We will now briefly outline the timeline for the creation of plants and animals.

 


a. Timeline for Land Plants

 

 

[Slide 10, right] Moving to land began seriously about 470 My ago, some 100 My after the Cambrian explosion. By this time corals, mollusks, and other sea creatures were long established. Some early fungi appeared at about 500 My and mosses about 470 My, both in the Ordovician era. These all lack real roots, so they can only be small and can only grow in water or wet surroundings. However, they could move from shorelines to the interior of land masses, provided the necessary bacteria had preceeded them to supply food and nitrogen, because they have the ability to go into a dormant state during dry periods. That ability to survive goes all the way back to the very first life, the cyanobacteria, over 3 billion years before the Cambrian age. We mentioned that remarkable ability to survive in a previous talk.

 

         Cosmic and solar radiation at this time was still severe, but for these simple plants, that was only an inconvenience, because every plant zapped by radiation became food for other plants. As long as their reproduction could keep ahead of the destruction, they were able to cope.

 

         The really serious issue was water, more precisely, the retention of water in the plants that were exposed to dry land and air. By the start of the Silurian age, 430 My ago, the algae and mosses appear with waxy coats that prevent drying out, and from this point they spread all over the dry land. The waxy coating is characteristic of all land plants from this time on.

 

         Club mosses show up around 420 My ago. They are the first fossils that have roots and a vascular system to transport dissolved minerals and water between the roots and the rest of the plant. At the same time, spores, which protect plant embryos in damp environments, appear. Club mosses are common and can be easily found in woodland environments at the base of trees and in other damp places.

 

         It is difficult to over-state the marvelous creative innovations that these roots, vascula and spores represent. The vascular system, for example, includes two separate systems called the xylem and phloem, for transport of food to and from the main body of the plant. Flow depends on capillary action and control of the concentration of dissolved material in the cells, so that osmotic pressure will cause water and solutes to move against gravity (osmotic pressure causes water movement toward cells that have a higher concentrations of dissolved material). Osmotic pressure also maintains the shape and rigidity of plants. Another innovation is the specialization of different parts of the plant for mineral absorption (roots) and food production.

 

         Ferns appeared next, about 400 My ago. Ferns have large leafs with a web of veins, an improvement over club mosses. Early fern trees and conifers appear about 50 My later, early in the Carboniferous era, about 370 My ago.

 

         Up to the mid-Carboniferous era, all the land plants live in swamps or very wet environments, because they do not have true roots and woody stems. This early part is called the Mississippian era. The latter half of the Carboniferous era, when true roots are created, is called the Pennsylvanian era. The carboniferous age is the time when many of the great coal deposits were made. Note that these deposits removed a lot of carbon from the environment. Note also that there were no large land animals to feed on the plant life, so that full ecological recycling did not take place.

 

         The next stage was the creation of two things almost simultaneously: winged insects and true seed plants. These show up in the fossil record at the end of the Pennsylvanian era, or the start of the Permian age, about 300 My ago. True seed plants are distinguished from spore-bearing plants by the fact that the seeds have true embryos, food and a hard coating for protection.

 

         This was the first time that land plants had the ability to spread throughout dry land, and were no longer tied to swamps or wet areas. This is also the first time that the ozone layer is completely in place and allowed plants to survive on dry land by shielding the land from solar and cosmic radiation. So, in fact, the seed plants, the first true dry land plants, were created as soon as survival on dry land was possible.

 

         A little later, about 280 My ago, beetles appear in the fossil record. After all you have to have something to chew at all the plants! We don’t have time to do it, but the beetles make a great study of the limits of species variation. As someone said, “God must love beetles, there are so many of them!”

 

         There was another mass extinction about 255 My ago, called the Permian extinction, in which 85% of all species of plants and animals die out. I don’t think the cause of the extinction is fully known, but it seems likely that it was the result of a large meteor hitting the earth, which might cause the oceans to evaporate, or cause a dense cloud of debris that would hide the sun for a period up to several years.

 

         After the Permian extinction, modern plants appear: Modern ferns, about 255 My (Triassic), fruiting plants about 200 My (Jurassic), and the most abundant modern plant species, the angiosperms, or flowering plants,  about 170 My ago. With these changes plants could spread to all of the dry land. The arrival of the angiosperms is announced in the fossil records by pollen grains; actual fossils of flowering plants start appearing about 40 My later, or 130 My ago.

 

[Slide 11] This is the overall story of the creation of plants. We have left out the most interesting part: a detailed discussion of all of the marvelous innovations involved in this creation. Each stage involved ingenious solutions to very difficult problems.[11] Here are some of them:

 

         • How to propagate and survive in extreme conditions.

                  Solutions: Spores, pollen, seeds.

            • How to avoid drying out in the atmosphere?

                  Solutions:

                           Cutin (waxy layer on leaves),

                           Stomata (openings in leaves)

         • How to get water and nutrients to plant extremities?

                  Solutions: roots and vascular system

                           Note: solution implies a complex control of solutes

                            and a mechanism for water transport.

         • How to support weight in air, maintain rigid form

                  Solution: root system to anchor in ground;

                           cellulose for low plants (osmotic pressure);

                           woody tissue for taller plants.

                 

b. Timeline for Land Animals.

 

[Slide 12] I would now like to give a quick overview of the creation of land animals, as I did for land plants.

 

 

         We already noted the creation of all of the basic body plans in the Cambrian era. After the Cambrian a number of great innovations within the Craniata, Phylum A-37, show up. These are designated A-37.1 through A-37.8 in the notation of Lynn Margulis. In my view, all or at least many of these separate classes are distinct Creative acts rather than natural developments from a common ancestor, mostly because I cannot fathom how the many innovations involved in the features of these classes would arise naturally.

 

         After the Cambrian explosion, the first jawless fish show up about 450 My ago, complete with a protected spinal cord and cranium. In my view this is the first proper evidence of the phylum Craniata, which includes most of the land animals you are familiar with.

 

         Jawed fish appeared a little later, about 390 My ago, including the Coelacanth, a “living fossil” that was long thought extinct until it was fished up in Madagascar in the 1940s. By this time, very elaborate embryonic developments are well in place, including internal and external development of the embryos. Note, for example, that coelacanths, among the earliest examples of jawed bony fish, give live birth. Most fish “are not that advanced.” They spawn and the embryos develop in water.

 

         In the Devonian age the first big move toward land animals occurs, about the same time as the first big marine animals. The first land animals are the amphibians -- think salamanders and later frogs. Amphibians are tied to water because fertilization and the early development stages take place in water, much as most fish do.

 

         Winged insects arrive about 340 My. This time marks another step in the move to dry land, as up to this time, life poked its head out of water only in swamps and marshes with lots of water nearby. Of course many of the winged insects still need water or at least moist environments, for the larval stage.

 

         Reptiles are the first land animals that fertilize internally and give birth alive or else have fully developed eggs with protective features such as a hard shell, and an initial food supply to nourish the embryo prior to birth. They show up about 300 My ago and are the first animals that can live on dry land without being tied to swamps and bodies of water. Note again the “coincidence” noted earlier, that they arrive at the first time that the ozone layer allows complex plant or animal life on dry land.

 

         After the Permian extinction (250 My ago) some of the modern plants and animals were created. No large animals survived the extinction, but some large fish such as the sharks and coelacanth, did. Mammals show up about 220 My ago, and birds show up in the Jurassic, 160 My ago, at about the same time as the modern flowering plants first appear.

 

         Birds came about only after a number of innovations: feathers, of course, but also special lungs, heart, bones and other features.

 

From this point, the land animals really take off with animals and plants arriving in great profusion.

 

         This has been a ridiculously fast sweep through the timeline for the creation of plants and animals. What is missing is a careful discussion of all of the marvelous innovations that are required at each stage. Even very minor features display marvelous complexity. Take, for example, the design of the stingers found in corals and jellyfish: the cnidaria or “stingers”. It is a marvel of engineering design.

 

The question of “Kind”: Natural Variation

 

[Slide 13] I would like to go back to the nonsense question and probe what the variation within a “kind” might look like. Specifically, I would like to look at two kinds of life that have very long fossil records. The first example is radiolarians, which are single-celled creatures, and the second example is the trilobite. Both creatures show up early in the Cambrian age. Radiolarians are still abundant today. The trilobites disappear from the fossil record during the Permian extinction, about 250 My ago.

 

a. Radiolarians.

 

A typical radiolarian[12]

 

[Slide 14] Radiolarians are found in the oceans world-wide. They are a variety of plankton, which means that they are free-floating. Many varieties are phosphorescent, and cause the familiar glow in a ship’s wake. They are distinguished by the fact that they usually have a hard shell that surrounds the cell nucleus and reproductive processes. The shell typically has many holes in it through which jelly-like pseudopods project to gather food.

 

[Slide 15, 16 ] There are many thousands of varieties of radiolarians. The biologist Ernst Haeckel, who was a contemporary with Darwin, produced a 3-volume systematic study of radiolarians in 1887 in connection with the 3-year biological expedition of H.M.S. Challenger, conducted during 1872-1875. Included in the study are 140 plates that show thousands of different radiolaria skeletons, a few of which are shown here. After the close of this talk, I will project all 140 plates so you can get an impression of the scope of skeletal shapes.

 

[Slide 17] In his report, Haeckel remarked:

 

The skeleton of the Radiolaria is developed in such exceedingly manifold and various shapes, and exhibits at the same time such  wonderful regularity and delicacy in its adjustments, that in both these respects the present group of Protista excels all other classes of the organic world. For, in spite of the fact that the Radiolarian organism always remains merely a single cell, it shows the potentiality of the highest complexity to which the process of skeleton formation can be brought by a single cell.”

 

Ernst Haeckel, Challenger Report on Radiolaria[13]

 

         When I contemplate the many radiolarian skeletal shapes, I am naturally drawn because of my mathematical background, to ask whether random and cumulative genetic changes might explain the great variety.

 

[Slide 18] Perhaps the most familiar analogy is to snow crystals, which I assume that most of us are familiar with. Snow crystals are the result of random microscopic variations in the “seeds” that grow the crystals. The apparent complexity is the result of relatively simple physical laws of crystal growth. I suppose someone could claim that God directly created each crystal, but it seems more reasonable, and quite adequate to assume that they grow naturally.

 

Snow Crystals[14]

 

[Slides 19] Another possible analogy is fractal design. Fractals are patterns that result from the repeated application of some very simple design rules with random variation added. Fractal designs have infinite variety, but at the same time have a recognizable overall appearance. The shapes that characterize varieties of trees and leaves can be duplicated using fractals. Every fern frond or maple leaf is different, but they have a characteristic underlying fractal design that can be described in a few lines of computer code.

 

[Slides 20] Many of the background landscapes in computer games are designed using fractals, and can be quite realistic. Here is a fractal arctic scene, with fractal clouds, icebergs and waves. I have also seen fractal mountain ranges and moonscapes.

 

         I conjecture that radiolarian skeletons arise by some similar random processes acting on the genetic code over time, although I confess that I do not know exactly what the underlying natural laws are. I do not see the need to invoke supernatural intervention to account for the huge variation. All the variation appears to be centered around a central basic body plan.[15]  The geometrical variations in the radiolaria are the working out of geometrical laws of design—like the snow crystals and fractals, but richer in the underlying “algorithms”.

 

b. Trilobites.

 

[Slide 21] Now let’s carry the question of the scope of kinds to a higher level, to the highly complex, but also quite varied, trilobites. The story of the trilobites is so amazing that I am convinced that they are an example of God’s providential grace in providing us with a case history to study the issues of creation and natural development.

 

         Trilobites first appear as a fully developed complex form about 570 My ago. They have no plausible fossil ancestor. They are among the earliest hard-bodied fossils to appear and they vanish from the fossil record at the time of the Permian extinction, more than 300 My later.

 

         Let us talk first about the basic body plan. Throughout the entire history of trilobites this basic plan was constant. It is the earliest fossil that has fully developed eyes. But that is only part of the amazing features of this creature. A trilobite has a hard exoskeleton. The name comes from the fact that the main body, the thorax, has a number of three-part segments. The soft parts are protected in an articulated shell, which is like armor plate that flexes between the segments (unlike a turtle shell, for example). Each segment has a pair of jointed legs, and gills tucked between the legs and the plate. The animal may (not all do) have segmented antennas and compound eyes in the head. We will say more about the eyes shortly.

 

Cambrian Trilobite age about 540 My[16]

 

[Slide 22] The internal features include a full digestive system, a respiratory system with gills, a circulatory system with a heart, muscles, a nervous system with a brain, nerve cord and ganglia and various sensor systems, most notably including compound eyes. And all of this appears suddenly in the fossil record, fully formed.

 

Trilobite body parts[17]

 

[Slide 23] You might well ask, how do we know the internal structure of the trilobite, since we only have fossils to go on and the internal anatomy is all soft-body parts? The answer is, in my view, another example of God’s gracious providence:

 

Some trilobites discovered near Rome, New York have had the hard and soft-body parts replaced by finely crystaline pyrite (FeS2). They display finely detailed external appendages and gills.  X-rays reveal fine details of muscular, digestive, circulatory, visual systems. As a result of this providential gift, much is known about trilobite anatomy despite the fact that they have been extinct for 250 million years.

Rolf Ludvigsen, Fossils of Ontario[18]

 

         Pyrite is known as “fool’s gold” because of its golden color. The soft-body parts of these pyratized fossils show up in xrays of the fossils. This discovery of pyratized fossils offers an extraordinary opportunity to learn about the trilobite anatomy. The author calls it “providential.” I agree. There is no room whatever to postulate a gradual, evolutionary development of the trilobite body plan. It just is there, right from the start of the animal fossil record.

 

[Slide 24] Trilobites persisted for over 300 My. Most of them were bottom feeders, although a few varieties appear from their streamlined form to have been swimmers. During this time, trilobites assume a fantastic array of body shapes and features, and come in sizes ranging from thousandths of an inch to tens of inches. An amazing range of body features appear to come and go over this 300 My span. Here are some examples from various geological ages.

Ordovician Trilobite

Ordovician Trilobite with stalk eyes

 

Ordovician Trilobite

 

Silurian trilobite[19]

 

Devonian Trilobite.

Note articulation

 

[slide 25] The Trilobite Eye. The trilobite eye provides a marvelous example of the kind of change that can be seen over this long Fossil record.[20]

 

First I should note that the trilobite eye is unique in the animal kingdom. Instead of being made of soft protein, as in the case of all other species, the trilobite has compound eyes of precisely oriented clear crystals of silica.

The focus is fixed and cannot be changed, unlike the human eye which can vary the focus with eye muscles—except I must ruefully note, when you grow old and the ability to focus begins to fail.

 

         There are two fundamentally different types of trilobite eyes.

 

a. The Holochroal (= “whole skin”) eye

 

         Most trilobites—all of the early trilobites— had an eye made up of many hexagonal cones of clear silicon that directed light down the axis to an optic receptor. Compound eyes are compact hexagonal prisms packed tightly in an arc or bulbous fashion and each cone in the compound eye could see directly along the cone axis. Thus the compound eye could see over a range of directions limited by the number and orientation of the cones. In some species the eyes were on stalks so that they could aim the cones to see over a range of directions. A compound eye may have as few as 30 or as many as 15,000 separate prisms.

 

The Holochroal eye, consisting of packed

hexagonal cones of silica crystal

 

b. The Schizochroal (= “split skin”) eye

 

         One group of trilobites, the Phacops, which appear late, in the Devonian era, had a very different kind of eye lens, called the schizochroal lens, consisting of a small roundish compound lens rather than a longish prism lens. The upper part of the compound lens was silica, but the lower part was another material with slightly different optical properties (possibly protein). The purpose of this compound lens was to focus the light into a concentrated spot much as modern compound microscopic lenses do. The two lens pieces with different indices of refraction joined to correct for spherical abberation, an annoying effect that is corrected by modern compound lenses. Each lens assembly is separated from its neighbors by an opaque wall to prevent scattering of light.

 

[Slide 26] There were two designs of these schizochroal lenses. One design used a spherically-shaped upper surface and the other design used an oval upper surface. Remarkably, work by Rene Descartes and Christopher Huygens in the 1600’s solved the spherical abberation problem in exactly the same way as the Phacops trilobite did 300 My before.[21]

 

The Schizochroal eye, consisting of

spherical simple or compound lenses of silica crystal.

 

 

Descartes’ lens (left) and trilobite Crozonaspis (right)

with a spherical lens surface.

Light rays coming from the left meet at a focus.

 

Huygens’ lens (left) and  trilobite Dalmanitina (right)

with an oval (elliptical) surface.

Light rays coming from the left meet at a focus.

 

Devonian Phacops with Schizochroal eyes[22]

 

[Slide 27] One obvious question is, how did trilobites come up with the two major versions of the crystalline eye, and what kinds of genetic change were required to do this?

 

         At first, the exquisite optimal design of the Schizochroal eye might incline a person to believe that it is a great example of direct fiat creation by God. But the surprising answer, surprising to me at least, is that the eye probably came about by natural, random changes in the eye design.

 

         The secret is this: both kinds of trilobite eye were present in the genetic code all the time, from the very first. All trilobite eyes begin in the embryonic stage as a more-or-less spherical shape, which grows into the prismatic crystals as the trilobite matures. So it appears that in Phacops, this embryonic lens persists through adulthood, whereas in all other species the embryonic lens grows into the holochroal prism lens.

 

         This arresting of normal embryonic development is called paedomorphosis, the retention of embryonic or juvenile features. I first encountered paedomorphosis as an explanation of the difference between human skulls and the skulls of other primates: the human skulls represent an earlier stage of maturation, so in effect the human skull retains some juvenile features. I must admit when I first heard this, I was not favorably impressed.

 

         But when you apply the insight to trilobites, it turns into a marvelous demonstration of how the original genetic code for the trilobites anticipates an eye development that occurred hundreds of million years later. This is a second example of genetic anticipation, adding to the armor of trilobites and crustaceans which existed before they needed it.

 

         Even the early geologists, as  they began to systematically  study the fossil record, noted this anticipation. Sir Charles Lyell, one of the great geologists of the mid-1800’s remarked:

 

"We must suppose that when the Author of Nature creates an animal or plant, all the possible circumstances in which its descendants are destined to live are foreseen, and that an organization is conferred upon it which will enable the species to perpetuate itself and survive under all the varying circumstances to which it must be inevitably exposed."[23]

 

         I believe that even though it seems to be evidence of careful engineering design, the remarkable focussing ability of the schizochroal eye is probably the result of natural development. I say this only because I think I could build a computer simulation that would come up with a focussed eye with a lens much like the Phacops eye. The random changes would be in the developmental genes: changing the speed of maturation of the eye, for example. The environmental payoff function would be the ability to focus and concentrate the light, and thus be able to see effectively in low light situations (such as moderately deep water). This would have a direct survival value, because it would directly increase the grazing range for the bottom-feeding trilobites with the phacops eye, compared with trilobites that could not focus as well.

 

         I have not actually written such a program, but based on my background with such simulations, I am confident that I could do so. The result would be a demonstration that natural random changes could produce an optimally focussing eye.

 

         But note what I am saying. I would start with all the necessary genes to produce the crystals; I am not making up novel kinds of genes, only slowing up or speeding up the rate of development. Everything is already there in the toolbox.

 

Significance of the Trilobite Fossil Record.

 

         I went into this extended discussion of trilobites to make some points about what the fossil record says about the creation process. I think a few points are worth noting.

 

         First, note that the complex body plan, including sexual reproduction, a full gut, circulatory system, nervous system, muscular system, fully developed eyes, and possible other sensor systems arose in complete form right at the start of the fossil record. The body plan appears to have almost every feature of the most advanced species, except for a spinal cord. 

 

         It seems particularly interesting that the eye, which must be one of the most complex of the sensor developments, appears right from the first. 

 

         If the remarks about paedomorphosis are accurate, then it would seem that all of the genetic code to cover all of the variations of the trilobites may well have been present from the very first. This is in essence to say that God created the genetic code for the trilobites and then natural processes produced the variations.  Of course this is not to say that God could not have intervened at any number of points, but it may be possible to show that the changes over time were already provided for in the first species that appeared.

 

But—and here is where I depart from evolutionists—I do not think that the genetic code needed for the eye’s very existence can by any means be had without an intelligent designer. On the contrary, I believe that the genetic code for the trilobite from the very first included the machinery to produce all of the eye variation that is found in the entire fossil record of trilobites.

 

Abundant Life

 

[Slide 28] The problems solved by plants and animals are not just solved in one or a few adequate ways, but in a multitude of ways, and often with great cleverness and ingenuity. In so many ways that some have suggested that nature displays every possible solution and every variation of the solution to these problems.

 

         Before Darwin came on the scene, it was commonly understood as a point of theology that God created all possible forms of life. That was part of God’s Glory displayed in nature. The French biologist Georges Cuvier argued in the early 1800’s that nature shows “all combinations that are not incoherent,” a form of a long existing “doctrine of plentitude.” Of course since Darwin, such an explanation has fallen into disfavor, but it has recently been re-asserted by Michael Denton, in his marvelous book Nature’s Destiny in which he devotes a fascinating chapter to just this point. He gives many example: all possible body forms, all possible eyes, all possible organism sizes, all possible methods to achieve respiration, circulation, and movement. I urge everyone here to get hold of that book and read at least that one chapter.

 

         Regarding the example of “all possible eyes” Denton wrote “it appears that every possibility has been realized in the design of image-forming optical devices.” He follows this up with a chapter on the eye of the Lobster. We have already seen some of the variation in our discussion of trilobite eyes. In addition there are examples of:

 

         • Amorphous (hard, soft) and crystalline lenses

         • Simple and compound eyes (multiple lenses)

         • Focusing and non-focusing

         • Reflective and refractive lenses

         • Simple and compound lenses with multiple refractive indices

         • Image formation by focussing and by scanning

         • A myriad of non-image forming light sensors

         • Sensitivity to various parts of the light spectrum

         • Passive and active (light generating) eyes

 

It does not seem to be an exaggeration to say, with Denton, that every sort of engineering solution to the problem of vision can be found in nature.

 

Think of any detail of biology and you will find a comprehensive array of solutions distributed among the various species of life. These solutions are not only found in the so-called “higher” plants and animals; even the most humble species solve their life problems in exceedingly ingenious ways. We briefly mentioned the stingers of the Cnidaria—the phylum of “stingers”. You could spend a lifetime marvelling at the many clever engineering solutions to just that one problem.

 

Conclusions

 

[Slide 29] I hope that this brief talk has given you some notion of the great and marvelous story of God’s creation of plants and animals that he has placed in the fossil record.

 

         The story is one of a creation that prepares the environment and then fills it with plants and animals that are suitable for the environment that he has prepared.

 

         The story of populating the dry land with plants and animals shows a gradual move to dry land that began in water, then moved to swamps and shorelines, and finally moved inland to dry land—preparing the food and the species for each step.

 

         This orderly plan does not prove random undirected evolution any more than the orderly plan for any large construction project proves that there were no blueprints.

 

         But God did not just leave us with this orderly record, he also gives fossil evidence that the most complex body plans arose suddenly in the record without logical precursors or an orderly progression of complexity. This is what one would expect from a Creator, but is not what one would expect from random undirected evolution.

 

         In God’s creation of body plans, there is evidence that the plans anticipated future needs or developments that were not present when they first show up in the fossil record. Examples are armor when there were no predators, and provision for the trilobite’s compound lens eye.

 

[Slide 30] With an adequate gene pool, natural change can produce an  astonishing range of body shapes and features. Examples that we have seen include the radiolarian skeletons and the trilobite eyes. Of course, many other examples could be cited, which has led Michael Denton and others to assert that plants and animals uses “every” way to solve the problems of life.

 

         Finally, although we did not dwell on the point, the fossil and geological history illustrates the fact that a stable ecosystem of plants and animals requires that all byproducts of life must be recycled, or the system breaks down eventually. We could point out examples in the carbon deposits of the Carboniferous age, in which carbon was not effectively recycled into the ecosystem, and the age of dinosaurs, in which huge animals dominated the land.

 

         Finally, I hope that you agree that the “Nonsense Question” is a reasonable thing to ask, and that seeking to answer it will provide much insight into how creation occurs.  From what I can determine, there remains a lot of work to do to answer it. I believe that the answer can be found by a careful examination of God’s fossil record of his creative activity and a deep understanding of genetics and embryonic development.

 

         I believe that God intends us to find the answers, and that it is for us to do the hard, honest, scientific work to get them.

 

Thank you.

 

David C. Bossard

November, 2001



[1]  Ernst Haeckel, The Radiolarians, 1887. Volume XVIII (2 tomes + atlas of 140 plates) of the Report on the Scientific Results of the Voyage of H.M.S. Challenger during the years 1873-1876  (50 volumes published between 1881 and 1895).

[2]  David C. Bossard, A Fit Place for Life: Creation of the Biosphere, IBRI Research Report #61, 2001, available at http://www.ibri.org.

[3] from http://www.emory.edu/COLLEGE/ENVS/research/ichnology/Graphics/Trichophycus.jpg:  a  horizontally  to obliquely oriented burrow presumed to be produced by  a large arthropod

[4]  The fossil burrows are known as Trichophycus pedum. In 1991 the International Subcommission on Cambrian Stratigraphy  officially set the Cambrian boundary at the first appearance of these fossils. See http://www.uni-wuerzburg.de/palaeontologie/Stuff/casu8.htm.

[5]  http://www.ucmp.berkeley.edu/arthropoda/trilobita/bergeroniellus.jpg. from Lena River Gorge, Siberia, early cambrian. See http://www.ucmp.berkeley.ed/cambrian/aldan.html. Photo by Jere H. Lipps.

 

[6] Richard Fortey, Trilobite! Eyewitness to Evolution, Alfred A. Knopf, 2000, p.121.

[7]  This description of the Hox genes follows Colin Tudge, The Variety of Life, Oxford, 2000, p183.

[8]  Following the nomenclature of Lynn Margulis et al, Five Kingdoms, 3rd Ec. W.H. Freeman, 1999. This nomenclature includes all vertebrates as Craniata; some extinct vertebrate species did not have Crania.

[9] Redrawn from Simon Conway Morris & H.B. Whittington, "The Animals of the Burgess Shale" Scientific American, 1979. Also in Rich&Fenton The Fossil Book, p 115.

[10]  http://www.uni-wuerzburg.de/palaeontologie/cscpic/phosg.jpg SEM micrograph of a hesslandonid phosphatocopine.  Oblique view. D. Walossek, Ulm. From the web page “Life in the Cambrian” at http://www.uni-wuerzburg.de/palaeontologie/Stuff/casu8.htm.

[11] An interesting summary is found in “The Problems of Becoming terrestrial” p372ff of Patricia and Thomas Rich, Mildred and Carroll Fenton, The Fossil Book: A Rrecord of Prehistoric Life, Dover, 1996.

[12]  http://www.pbrc.hawaii.edu/bemf/microangela/mradiolo.jpg.

[13]  Ernst Haeckel, Zoology, Vol XVIII Report on the Radiolaria collected by H.M.S. Challenger, 1887, in Report on the Scientific results of the Voyage of H.M.S. Challenger during the years 1873-1876.

[14]  from http://www.lowtem.hokudai.ac.jp/~frkw/english/

[15]  D’Arcy Wentworth Thompson On Growth and Form, Revised ed. Dover 1992, has an extensive discussion of the geometric origins of the radiolarian skeletons (p.694-731).

[16] Paradoxides gracilis Jinetz, Bohemia.  approx. 4.5" long. Plate I, Levi-Setti Trilobites

[17] From Trilobite Internal Anatomy  at  http://www.aloha.net/~smgon/trilointernal.htm

[18] Rolf Ludvigsen, Fossils of Ontario Part 1: the Trilobites, Royal Ontario Museum, 1979, p22.

[19] Arctinurus occidentalis Hall Silurian Rochester Shale Lockport NY. Plate 45 Levi-Setti Trilobites. Photo by author. Pyritized fossil?

[20]  Much of the information here is from S.M. Gon III, The Trilobite Eye which is located at http://www.aloha.net/~smgon/eyes.htm. The images of the eye types are from this web site unless otherwise noted.

[21]  This was first reported in 1975 in Euan N.K. Clarkson, Riccardo Levi-Setti, Trilobite eyes and the optics of Des Cartes and Huygens, Nature, 254 (April 24, 1975), 663-667.  The diagrams and discussion here  are redrawn from that article and appear in S.M. Gon III, op. cit.

 

[22] Plate 201 Levi-Setti photo by author. Devonian Phacops megalomanicus (Struve), Alnif Morocco

[23] Sir Charles Lyell, Principles of Geology, 8th Edition, 1850, p560.