Earlier this year I gave a talk for the U3A group in Kyneton. I decided to present the following material which has fascinated me ever since I first saw David Attenborough’s “Life on Earth” in the mid 1970s.

After that, of course, I discovered Darwin and Russell. Because I lacked a proper scientific education from my school days I had a lot of catching up to do. Further down the line we got the internet and I didn’t have to go to libraries or buy books, the whole world was laid open offering items which I discovered at my leisure from the comfort of my armchair.

So I wondered if the good folk of the Kyneton U3A might like to take a trip down the memory lane of planet Earth, specifically the miracle of how life gets started.

How do creatures get started?

Let’s start with a very small miracle, this tiny creature is “becoming” something… what it will become is a creature we call a “NEWT”.

	The Alpine Newt

Newts are part of the “salamander” family found in North America, Europe, North Africa and Asia…

the one we’re about to watch developing for a few minutes in the next clip will eventually become a fine little creature just like this (to the right).

How do they become what we know them to be?

BECOMING (a short film by Jan van IJken)

I wonder how many of you have hatched chickens from fertilised eggs?

Some years ago I used to incubate chicks. I found that a fascinating experience. I never got tired of seeing the hatchings occur. I never worked out “which came first, the chicken or the egg?” but I’m sure you’re all going to help me solve this conundrum which has puzzled me all my life.

I loved the sound of the incubating chicks “pipping” while still completely inside their eggshells and that’s the sound which indicates that they’re just about to emerge after pecking the shell away.

On day 20, the chick pierces the membrane into the air chamber. The chick breathes air for the first time, and you may hear the chick cheeping inside the egg. This is called “pipping”. On the 21st day, the chick begins to break out of the shell.

Now those time estimates may be fairly accurate but I noticed that some little critters begin to emerge before their companions and some are pretty slow to come out of their shells, so I guess those timings are really only “averages”.

CHICK HATCHING:

In those days when I was hatching chicks I was told that the temperature set in the incubator determined the sex of the hatchlings. So I was always puzzled if this was true and recently on the net I found out these answers to my questions:

Is Sex determined by incubation temperature?

The sex of an individual is determined by a relatively small number of genes, which, in most animals, resides on a particular chromosome, in the case of mammals, the XY or XX pairs. Even in species where sex determination is affected by developmental temperature, the genetic makeup doesn’t change with temperature. What does change is the expression of certain genes.

Further to that:

What temperature settings change the number of males which survive compared to female chicks?

In laboratory studies, incubating “Emys” turtle eggs at temperatures above 30°C produces all females, while temperatures below 25°C produce all-male broods. The threshold temperature (at which the sex ratio is even) is 28.5°C (Pieau et al. 1994).

Now, keep in mind that what you're doing is not changing the sex of the chick inside the egg - that's been predetermined - but for whatever reason, male embryos seem to be more sensitive to low temperatures, causing some of them to fail to hatch.

So that seems to have solved one puzzle but it has not solved the big question… “which came first, the chicken or the egg?”

My friend Ian Gibbins says:

The answer here is clearly the egg.

Birds evolved from egg-laying dinosaurs.

Nearly all creatures lay eggs.

Even those that give birth to live young, such as ourselves, have eggs: they just develop internally.

It’s not actually a conundrum at all, at least not for a long time now.

MOTHER NATURE HAS MANY PUZZLES
FOR US TO SOLVE.

SOME OF THE TIMINGS OF THE REPRODUCTIVE CYCLES OF DIFFERENT SPECIES ARE INCREDIBLY PUZZLING. HERE’S ONE WHICH I THINK WILL ENTERTAIN YOU ALL…

THE PERIODICAL CICADA:

14 years or 17 years … in either case why so long?

I want you to know that Sir David is my patron saint!

Over the years he has endeared himself to many of us in many countries. I first got the bug when he released Life on Earth way back in the 1970s, when I was still becoming the person I am today.

In those days I didn’t know there were two distinct families of the periodical cicada. One has a 14 year life cycle, the other has a 17 year life cycle.

I have written more on this in my blog:

https://petertammer.blogspot.com/2021/04/everything-you-ever-needed-to-know.html

Many other puzzles such as those we have just seen were raised for me by Sir David, as well as other people such as David Suzuki.

David Suzuki grabbed my attention with his discussions about North American Atlantic salmon who like to spawn and die in the rivers where their female parents laid eggs, fertilised by the males, who all died. Then those eggs became fingerlings which set off into the Pacific Ocean for many years developing into adult salmon.

Responding to some inner clockwork as they near the end of their lives they return to the rivers where their lives began, to spawn another generation before they die.

How do salmon know where their home is when they return from the ocean?

ONE SOURCE SAYS THIS:

Salmon come back to the stream where they were 'born' because they 'know' it is a good place to spawn; they won't waste time looking for a stream with good habitat and other salmon.

Scientists believe that salmon navigate by using the earth’s magnetic field like a compass. When they find the river they came from, they start using their sense of smell to find their way back to their home stream. They build their 'smell memory-bank' when they start migrating to the ocean as young fish.

If a salmon can’t find its stream, some continue to search for the right stream until they use up all their energy and die, but most simply try to find other salmon with which to spawn.

EELS

I’ve heard that eels do something similar, but this is a hugely contentious area… let’s leave it for another scholar and another day.

Now we move away from little critters in the animal kingdom to consider that other huge family: FLORA!

Flora and Fauna are two huge families of life on Earth both of which only got started about 560 million years ago.

Did I say “only” 560 million years ago”? Yes I did!

Plants and Animals are kingdoms, which along with Fungi make up the three great divisions of multicellular life.

Some of the earliest multicellular creatures became recognisable in fossils laid down 560 million years ago.

These earliest fossils have been found in the Burgess Shale of Canada and the Ediacaran Formation of South Australia.

But these fossilised creatures themselves must have evolved well before then, usually estimated to be around 650 million years ago.

The earliest multicellular creatures probably evolved about 1 billion years ago based in estimated rates of evolution. At this point they were already differentiated from photosynthetic plants (which were then mostly algae).

There is yet another huge event in the life of Planet Earth which has puzzled the best scientific minds over a couple of hundred years. That is how did we get our oxygen?

It may have have got started about 3.5 BILLION years ago. But there is uncertainty about this.

The levels of oxygen dramatically rose in the atmosphere around 2.4 billion years ago, but why it happened then has been debated. Some scientists think that 2.4 billion years ago is when organisms called cyanobacteria first evolved, which could perform oxygen-producing (oxygenic) photosynthesis.

It is difficult for scientists to figure out when the first oxygen-producers evolved using the rock record on Earth. The older the rocks, the rarer they are, and the harder it is to prove conclusively that any fossil microbes found in these ancient rocks used or produced any amount of oxygen.

The answer in general is that oxygen is a gift from the plant world, they inhale carbon dioxide and exhale oxygen. Over 2.4 BILLION years they changed the composition of our atmosphere from toxic to life supporting.

From Ian Gibbins:

Cyanobacteria were the original oxygen producing organisms and in many respects they still are.

They are still abundant in the waters of the world.

Multicellular plants definitely produce most of the earth’s oxygen now but they didn’t appear until long after the Cyanobacteria.

We could say that Cyanobacteria are still producing all the oxygen, since there is very good evidence that chloroplasts, the photosynthetic components of green plants (including algae) have evolved from Cyanobacteria living symbiotically within plant cells.

Now we’ll talk about “bigness” and “smallness”.

What are the smallest flowers and smallest creatures?

IS THIS JUST A LAYER OF SLUDGE ON THE SURFACE OF A POND?

ACTUALLY IT’S FORMED BY THE TINIEST FLOWERING PLANTS!

As you all know, there are many microscopic creatures in the animal kingdom and we humans really don’t like them, and other animals don’t like them, but we just can’t seem to get rid of them. Flies, mossies and spiders? Well they are small but let’s go even smaller.

Fleas, lice, mites, ticks and bedbugs.

Ticks — the blood-sucking, Lyme disease-carrying subclass cousin of mites — are considered the largest of the kind, but most mites are much smaller.

The tiniest mite on record is 82 microns long.

That’s barely one third the width of a human hair.

Speaking of mites that feed on human material, Demodex folliculorum is one of three mite species living on your face. The microscopic critters are found across the human body, but are particularly dense near the nose, eyebrows and eyelashes. They live in the body’s hair follicles feeding on the gland’s secreted oils.

A TINY BUG

THE SAME BUG magnified

ARMADILLO (Mite)

A GANG OF MINI ARMADILLOS

BED BUGS and DUST MITES

DUSTMITE

Now I know you will find what I’m going to ask is a bit silly, but how do these tiny creatures know how to go about their business?

	Home Sweet Home

If their business is to find a home in your eyelashes, or your nostril, or your belly button, how do they know that is where they will be most happy?

And when I ask this question I know I am using a word which is quite crazy… how could a creature like a mite or a midge “know” anything, given that its body is so small, its brain (if it has one) would be incredibly small, so how do they function? How do they know what they have to do to survive?

From Ian Gibbins:

All these organisms have a nervous system and part of that is specialised into a brain.

The only animals without an obvious brain are coelenterates, e.g., corals, jellyfish, and their relatives, but they do have a nervous system.

All cells are about the same size. Smaller animals just have fewer of them. So the brain doesn’t need to be so big to control a small body.

A remarkable thing about all nervous systems is that they are somehow preprogrammed to generate the behaviour typical of any given species.

No one really knows how this is achieved.

Maybe, like lots of people in our human species, they don’t know anything at all, perhaps they just do whatever seems appropriate, and for some it is to live in your mattress, for others it is to live in your eyelashes, while yet others prefer to live in the follicles of your nether regions.

That’s where they choose to make their home!

There you go, I’ve done it again… another silly word: “CHOOSE”?

Well, if they don’t choose, how do they end up where they do?

Most creatures like to have a home and some of them have to build their own home despite the fact that they are incredibly tiny, despite the fact that their brain size must be pitifully small, but even so they may manage to build themselves a nice little home.

Building a home!

Every shell on every beach is a home made by some little critter who was following a plan… but what did it know of the plan?

The plan was laid out in the code contained in DNA which originated millions of years before there was any such crittur as a sea snail, or a mussel, or an oyster… yet it seems that all these little characters just like to follow the plan which has been laid down for them.

From Ian Gibbins:

	Polymita snail

Each species of snail has very specific genetic code that, amongst other things, determines the size, shape, and pattern of the shell.

Of course, this code has been inherited from predecessors, but it is changing all the (geological/evolutionary) time and it is unique to the particular species in question.

All snails will have some elements of that code in common (e.g., to make a spiral shell) but the details will be affected by specific variants of the genes that control the generation of the shell.

The interaction between different levels of genetic expression and other developmental factors has been quite well studied for some molluscs.

One of my favourite creatures is the Caddis Fly Larva. This little blighter has not yet become an adult Caddis Fly because it is still in the process of becoming one. It just hasn’t made it yet! If it doesn’t get eaten by some fish or other predator, it will eventually become a Caddis Fly.

These little blighters are so beloved of trout that fishermen and fisherwomen go to enormous lengths to make “replicas” to use as bait skimming over the water.

The larva is only the juvenile version of the fly, and yet this insignificant miniscule creature is a most extraordinary builder.

THE CADDIS FLY LARVA:

Attracting a mate!

But some creatures don’t build just to make a home, some are like us and like to create things of beauty.

WHY WOULD THEY DO THIS?

DO THEY THINK THEY ARE ARTISTS?

PUFFERFISH MANDALA:

BOWERBIRDS:

Sir David on the Vogelkop bowerbird

ANIMAL PLAYFULNESS

I’ve always been amazed when I watch animals at play.

Because I have a large number of magpies near my home, they seem to have adopted me or maybe they just like what little offerings I give them in the way of crumbs and leftovers. Anyway, I have a constant source of magpie behaviour to entertain me.

One magpie was swinging/trapezing, on a long bark frond hanging from a gum tree outside my window. A second one was watching and possibly learning the newly acquired skills of his sibling.

It was playful activity. I had seen them there a couple of times before I filmed them.

SADLY I CAN’T SHOW YOU THE IMAGES AS YOUTUBE DELETED THEM!

I had posted those images with music wich was playing in my living room as I filmed the birds. Youtube pulled the whole clip for reasons of abuse of copyright! When they did that I lost my last copy of that event.

My magpies are extremely territorial and don’t like many other creatures coming into what they perceive as their space. An extreme example of their “entitlement” can be seen in the next clip where two magpies seem to be completely unfazed by a fox, and the fox just doesn’t seem to know what to do about the situation.

FOX AND MAGPIES (possibly they are PeeWees):

Magpies & Magpie Larks (Pee Wee)

Whenever I leave food for the birds on my patio the Wattlebirds are so shy they just hold back nervously and wait till the magpies have gone away.

Crows, despite being as large or even larger than the Magpies, are just too scared to intrude. One Magpie can easily fight off two crows!

I’ve noticed that my Magpies do tolerate the presence of PeeWees (Magpie larks, although they are magpie coloured they’re not actually magpies at all) on my front lawn, which is the entire river reserve, but the maggies won’t accept any crows at all.

Compare the beaks!

MAGPIE and PEE WEE

Maybe the magpies think PeeWees are just “sort of” magpies? Almost magpies?

The intelligence of creatures:

EXPRESSING MEANING

Animals who remember their human friends

And even thank those who helped them

And even get them to do something for them

ELORA AND EGBERT:

CLEVER CROW:

A puzzle solving crow works out the 8 steps required to get food:

HUGE TREES

After I retired from teaching in 1998 I relocated to Denver, near Daylesford in Central Victoria. I planted shrubs and trees. I bought fruit trees and started a blueberry plantation of about 150 shrubs.

I also bought several mulberry trees, smallish, about 1.5 metres tall. They were not doing very well because the soil on my property was quite impoverished and I still had a lot to learn about soil.

One day I was invited to dinner with Fiona and Rob, friends in Castlemaine who had a large mulberry tree growing on their property. This was no skinny little wimp of a tree, I would say it was taller than a block of flats 4 storeys high!

It had never occurred to me that any of my puny little shrubs could possibly become such a splendid specimen starting from a seed the size of a raspberry or blackberry.

This image is not a picture of that tree, but is listed as the largest Mulberry tree in Australia:

I don’t think any of the orphans I left behind would ever make it to such a splendid size.

But it did get me thinking about the relative sizes of trees compared to the size of their seeds.

TREATY OAK

ARBOL-DEL-TULE

LOCATED INSIDE A GATED CHURCHYARD in the picturesque town of Santa Maria del Tule, the Árbol del Tule is the widest tree in the world.

The local Zapotecs like to joke that the Tule shares some of their characteristics: it is short (only 35.4 meters in height), stout (11.62 meters in diameter), and old (about 1,500 years). Indeed the Montezuma Cypress (Taxodium mucronatum) is roughly as old as nearby Mitla, the Zapotec religious site whose ruins draw visitors east from Oaxaca.

Once thought to be so large that it could only have resulted from a merger between multiple trees, modern DNA analysis has confirmed that the Tule is, in fact, a single individual.

Though it is the Tule’s spectacular girth that earns it a place in the record books, it is its gnarled bark that truly inspires the imagination. In its knots and crooks, visitors have found likenesses of human faces, lions, jaguars, elephants, and a veritable bestiary of other creatures.

The Tule Tree is still growing.

CENTURION 327.5 Feet (100 Meters)

Centurion, in Arve Valley, Tasmania, Australia, is the world's tallest known individual Eucalyptus regnans tree; meaning it's the tallest tree of one of the tallest tree species in the world. Which is a pretty special claim to fame; that this tree is featured on the Tasmania Facebook page says a lot about its popularity.

The CALIFORNIAN REDWOOD and the SEQUOIA

Sequoias and giant redwoods are often referred to as if they are of the same species.

They are two very different, though equally remarkable, species of tree. Both naturally occurring only in California, these two species share a distinctive cinnamon-coloured bark and the proclivity for growing to overwhelming heights.

But as you will find out later, they start off pretty small!

In fact many of the extremely large trees around the world grow from incredibly small seeds.

Like all the other plants we are surrounded by, over millions of years they have produced the atmosphere we breathe.

Without the oxygen they make we would not be able to live.

The process by which they’ve made the oxygen is called photosynthesis and it’s one of the great miracles of the Universe, the basis for a huge percentage of life on Earth

To love plants is to be in awe of photosynthesis. Even when you know how it works, it’s still a miracle, a crucial, “we-wouldn’t-be-here-without-it” miracle. Its ramifications are so vast that once it showed up, it dictated all of the evolution that followed.

I was greatly surprised when a dear friend told me that there is an equation for PHOTOSYNTHESIS.

Not being trained in science it never occurred to me that such a hugely significant process could be contained in a simple equation:

The process of photosynthesis is commonly written as:

This means that the reactants, six carbon dioxide molecules and six water molecules, are converted by light energy captured by chlorophyll (implied by the arrow) into a sugar molecule and six oxygen molecules, the products. The sugar is used by the organism, and the oxygen is released as a by-product.

The following clip is an animation representing the mechanisms inside a leaf by which carbon dioxide is converted to oxygen.

INSIDE A LEAF:

TUNNEL TREE

The leaves of the redwood tree are tiny machines which assist the tree to grow to its astonishing height, but then along come modern humans who like to play tricks with such a tree.

https://gulfnews.com/world/americas/storms-topple-californias-iconic-tunnel-tree-1.1959483

How large are the seeds which produce such giants?

Seeds of Californian Redwood

Pine nuts

Brazil nuts

Brazil nuts, inside a cut shell

BRAZIL TREE

As you can see from what I’ve shown here, there are no rules! Some smaller trees have large seeds and some huge trees grow from extremely small seeds. An avocado has a very large seed compared with a pine nut, but the small seeds of a cypress produce very large trees.

These seeds which produce various shrubs and trees of whatever size will grow anywhere they find a good opportunity!

From Ian Gibbins:

The actual germinal part of a seed is nearly always small… it starts as a single cell, equivalent to an egg.

What affects the size of what we call the seeds is the amount of additional material surrounding the germ.

This can be either mostly protein (as in beans) or carbohydrate (as in wheat), or more usually a combination of both, with various amounts of fats included in the mix as well.

These ingredients provide the energy for the initial stages of growth. Additional nutrients may come from surrounding fruit.

The main function of all fruit is for the seeds to be eaten and transported somewhere else to germinate.

They probably will not grow on a rocky surface but they can get started in cracks and crevasses, including cracks in road pavement.

Sometimes a tree will grow in a crack in a boulder and split that boulder apart.

Generally speaking they need SOIL, and the better the soil the better their chance of growing to fruition.

But soil is not just supplied, it is MADE!

Soil is the result of a process which has been going on for many millions of years. This process relates to all those creatures which live on the surface of the Earth and all the creatures which live inside the soil. Plants grow and die, creatures grow and die, then they all decay and become soil.

They are assisted in being reduced to soil with the help they get from scavengers, insects and worms. The very best soil is created in areas when lots of plants and animals have lived and died. Barren land which makes it difficult for plants to live and for animals to feed remain desert like.

But much more of the breakdown is done by fungi and microorganisms, including bacteria and protozoans.

Never underestimate the power of the lowly worm or the ubiquitous nematode. Their contribution to the planet is immense.

Just going back to the case of the periodical cicada, I wonder what it’s doing down there underground for 14 or 17 years.

Is it doing nothing?

Is it just lying around in a larval state until a timing setting in its DNA triggers its rise to the surface.

Or is it just feeding down there? Here’s what I found:

The cicada life cycle includes eggs, nymphs and adults.

All cicadas begin their lives as eggs. Their mothers lay the eggs in the branches and leaves of trees. The eggs hatch about two months later.

When the hatchlings come out of their eggs, they fall off the trees and land on the ground. Once there, they burrow into the ground. Inside their burrows, they feed on sap from surrounding plant roots.

They stay underground until they develop fully as adults. The time this takes depends on many factors, including local weather conditions.

Cicadas can’t emerge as adults until the weather is warm enough for mating.

Once conditions are right and they reach adulthood, the cicadas emerge from the ground and fly to the nearby trees.

Adults have a short life. They last about four weeks before dying or being eaten by other animals. During that time, they mate, lay eggs and start the whole cycle over again.

https://a-z-animals.com/blog/why-do-cicadas-only-come-out-every-17-years/

So what is the link between everything
I’ve raised today?

All living things start off small before they get big! Whether they are newts or chicks, elephants or blue whales, they start off as a small item we call an egg… or if we want to be really “erudite” we might call it an ovum!

Whether they are tiny flowers, grasses, medium sized shrubs or huge trees they all start off with a seed.

These eggs and these seeds contain all the information required to direct them to grow into the shape they will eventually become.

* * * * * * *

At the end of my presentation I was really chuffed how much the people there enjoyed it. It seems that much of what I presented was new to them and many of the clips astonished them.

I had a little surprise to give them just before afternoon tea.

I had bought an assortment of nuts at the supermarket and placed them in a bowl… all sorts:

Cashews, Walnuts, Brazil nuts, Macadamia nuts, Pine nuts etc.

Then I passed them around and told each person:

"If you take this bowl of nuts you can go and plant a forest on Mars!"

And that’s the subject of my next instalment!

Peter Tammer    22/12/2023

I would like to acknowledge the contribution of two fine friends who have assisted me in putting this all together:

IAN GIBBINS who kindly checked out many parts of the essay to explain things more clearly and to clarify some points I had raised which were a bit iffy:

in case you were wondering…

And 

Bill has been the Editor of all the pieces I have posted on my writings page. He has assisted me with all these pieces for so many years I have lost count.

I don’t think I would have completed any of my writings without Bill’s continuing support and attention to detail.