Richard Fortey, Survivors, 2011.


65M years ago: great extinction (dinosaurs); 251M years ago: great extinction; 2.5B years ago: snowball earth, oxygenated atmosphere develops.

Delaware, US (horseshoe crabs). Whereas we have hemoglobin as oxygen-carrying pigment, which include iron, the horseshoe crab carries a copper-based molecule to do a similar job. 450M years old outliving the trilobite (died 250M years ago) thanks to their more advance immune system (even if their exoskeleton was less robust than that of the trilobites. Eyes of horseshoe crabs are attuned to seeking out mates.

Solnhofen, Bavaria, Germany. Limestone of Jurassic age -150M years old. From time to time lagoon became salty enough from evaporation to poison living organism. Its deeper part were depleted in oxygen sufficiently to deter scavengers.

Arouca, Portugal for Trilobites.  With fossil examples of trilobites overlapping bodies recalling the struggle for mating among horseshoe crabs.

New Zealand was nascent 100M years ago. South Island new Karamea, in podocarp forest for velvet worm.

Many scientist believe that at some stage in new Zealand history the sea level rose to a point where mammal species could not endure and breed. Today it has no endemic terrestrial mammals. And the loss of ability to fly is common among birds – why bother? (kiwi, the moa – the largest ever bird to live on land)

Burgess shale rock formation, British Columbia, Canada. Mount Field in the Rocky Mountains. 500M ?

Chengjiang in the Yunnan province in China (shale of the Maotianshan formation) -500M  Cambrian.

Ediacara Hills, flinders ranges in South Australia. (635M-542M): Ediacaran animals were not obvious ancestors of the animal we know from the Cambrian onwards: they were inhabitant of a world that did not survive. Found also in 30 sites including Newfoundland (eastern Canada), arctic Russia and great Britain…

Messel pit, Germany, shale from Eocene period – 47M years ago (The link)

It seems tha Precambrian organisms (before 500M years to 4.5B) favored fractal structures.

Mistaken point Ecological Reserve (Newfoundland Canada): Precambrian fossils.

Charnwood forest in Leicestershire, England (Ediacaran fossils).

Some of the Ediacaran animals are symmetrical about a line running along their midriff. These animals could be place in Bilateralia – left and right sides are mirror images (as opposed to radially symmetrical like echinoderms)

Edicarian animals: the organisms preserved there are a kingdom (like Animalia) that has become extinct. Some of these animals may have harbored bacteria in their body compartments in some kind of symbiosis. Some seem to show a front end – a head.

Shark bay, Australia, Stromatolites. Hamelin pool, 47km out to the sea. Protected from marine animals, who chomped and scraped away ancient biological structures, stromatolites can grow.

Cyanobacteria cooperate: the living skin is a thin layer of growing threads matted and twined together. Attracted to light they grow upward. They grow very slowly at .3 to 1 mm a year. Over much of the Precambrian there was nothing to prevent tiny organisms from constructing a variety of edifices. Fossils dated at 3.5B have been found in the Apex Chert in Western Australia and in Swaziland (doubt have been cast on their authenticity).

Many early stromatolites were fully submarine, rather than living between tides. Their living analogues have been found in the Bahamas, near Exuma Island.

Between 850-635M years ago, snowball Earths are claimed to have happened on 2 occasion (and maybe more).

It is cleared that red algae and green algae are separate evolutionary packages put together by an independent history of endosymbiosis.

Once something was feeding on something else, natural selection favored anything that offered increased protection.

The means of transporting that energy within the cell is the chemical Adenosine triphosphate (ATP). This is just one fact that makes it likely that all life descended from a common ancestor.

3 domains: archaea, bacteria and eukaryotes.

Archae have cell membranes containing lipids that are different from those in the 2 other domains. Ribosome are the sites where protein created from instructions of ribonucleic acid (RNA): the three domains have ribosomes but major differences in the sequences of the RNA. It seems that archaea are closer to eukaryotes than bacteria (i.e. sharing a more recent ancestor).

Where there is energy to be derived, there will be a simple cell to utilize it, whether it is sulfur bathed in hot acid, or hydrogen or iron.

Carbon comes in 2 forms: C12 and C13.  Life favor the first as it is preferentially selected by the enzyme Rubisco – essential to photosynthesis – and thence become incorporated into organic matter. Carbon from meteorites is more C13. As far as we know only life can perform this trick.

We know now that organic carbon (C12) was plentiful at 3.5B. Late heavy bombardment 3.9B.

Using virus as vectors, genetic material can be exchanged across the species boundaries.. In fact such exchanges proves to be common place at bacterial level.

Cellulose cannot be digested without the help of enzymes produced by symbiotic microbes housed in the rumen of these animals.

We could do without the horseshoe crab of the velvet worm, but we would be lost without bacteria. The story of life is about communal shelter and mutual benefit.

Grand Teton national park, US,  (rocky mountains)
the pines could not grow without the help from symbiotic fungi coating their roots and scavenging phosphates from the soil, molecules by molecules.
Hong Kong, seas and beaches, lingula (small mollusk) 500M year old. Colonized land before the plants came in some 400M years ago.
Cambrian rocks in Oman
Turatao Island, Thailand for Ordovician rocks.

Sponges are not symmetrical. They can assume any form, no nervous system, no stomach but they reproduce sexually. Fossils of sponges are familiar in Cambrian rock but they used to live happily in shallow waters. They seem to have retreated to the deeps today. Sponges were identified some 650M years ago. Some suggest that sponges may belong to a group on their own, aside from animal evolution.

Medusae belong to the much larger phylum cnidarian. These kind of jellyfish have another way of arranging their anatomy if they are attached to the bottom of the sea ; sea anemone (a floating animal turned upside down.  Coral and jelly fish arrived after the sponges but before the bilaterally symmetrical animals. No coral in Cambrian rocks, the trick of building limy skeletons was not acquired for another 50M years (Ordovician).
Coral from today are not descending from those first coral who disappeared with the Permian extinction.
Norway for huperzia, first plant from 300M. Used to be a tree – contributing ultimately to the formation of coal and oil – and now it is a herb. Fossils are also found in Rhynie Chert, in Scotland.
Carboniferous: the first days of plants on lands some 420M years ago.
Despite their luxuriance, few ferns provide nibble for animals. They have been around for far too long (350M) and developed chemical defenses. Only a few insects can make a meal out of it. They are the first colonizers after a disaster (after volcano eruptions, even after the extinction of dinosaurs).
Araucaria – tree- in New Caledonia. Originate from Gondwana (everywhere from South America to Australia). 200M years ago. Northern hemisphere trees did not survive the 65M extinction.
Namibia, Welwitschia mirabilis, can live more than a thousand year.

Eucalyptus has traded in leaves for photosynthesizing directly from its green twigs.
The platypus genome is a combination of reptilians and mammalian characteristics, with no less than 10 sex chromosomes.

Feathers were initially not used for flight, but rather for insulation and possibly decoration.
A feature that appeared for one purpose was recruited for quite another.
Homo floresiensis: discovered in 2004. Dated as recent as 12000.  The hobbit showed distinctive features and it is possible they evolved entirely separate from the leading modern humans. May have be an offshoot of early migration out of Africa a million year ago. Became isolated on the island and became smaller….
Native people living in harmony with nature – Rousseau. But there has been a lot of man made extinctions (Moa, dodo etc.)

The great oxidation event at 2.4M years ago. When cyanobacteria introduced a significant level of oxygen into the atmosphere, the effect on prokaryotes must have been devastating.

Snowball earth – glaciation some 650M years ago (so its proponent believe). After the freeze, Ediacaran fauna followed (was it the end of an era or the beginning of a new one).

250M Permian extinction, 90% of species become extinct. Volcanic eruption of the Siberian trap is the proximal cause (on one continent, the Pangaea) spewing out millions of tons of sulfur and carbon dioxide in the atmosphere. Then 65M year ago (end of cretaceous).

99% of all species that have lived on the earth have become extinct.