Animal Evolution and Major Extinction Events

Species-scape

Visual representation of species size and diversity.

Earth's Age

~4.6 billion years based on radioisotope dating.

Oldest Rocks

Dated to ~4.4 - 4.2 billion years ago.

Phanerozoic

Eon from 543 million years ago to present.

Archean Bacteria

Original extremophiles, indicating early life forms.

Cyanobacteria

Photosynthetic bacteria that produce oxygen.

Great Oxidation Event

Oxygen increase due to cyanobacteria activity.

Anoxygenic Photosynthesis

Photosynthesis without oxygen production, using H2S.

Cambrian Explosion

Rapid diversification of animal phyla ~541-485 million years ago.

Late Ordovician Mass Extinction

First of five major extinctions, ~53-85% marine loss.

Icehouse Earth

Period with glaciers at both poles.

Great Ordovician Biodiversification Event

Increase in global diversity linked to oxygen rise.

Paleozoic Land Invasions

Transition of life from water to land.

Late Devonian Mass Extinction

Second major extinction, ~70% species loss.

Oxygen Delivery System

Evolved hemoglobin for efficient oxygen transport.

Permian-Triassic Boundary

Largest mass extinction, ~80% marine species lost.

Great Dying

Nickname for the Permian-Triassic extinction event.

Synapsids

Mammal-like reptiles before dinosaurs' rise.

Archosaurian Reptiles

Reptiles that include dinosaurs, post-Permian.

Coal Gap

Period lacking decaying plant matter post-Permian.

Oxygen Diffusion Gradient

Limit for cellular viability within 100uM of atmosphere.

Electron Transport Chain

Process evolved from endosymbiosis for ATP production.

Photosynthetic Organisms

Capture sunlight energy, producing glucose and oxygen.

Marine Fauna Diversification

Adaptation of marine species to cold habitats.

Problematic Fossils

Fossils hard to classify due to orientation.