#1: the history of life on earth.

ecology

the study of the relationships between living organisms, including humans, and their physical environment

4.6 billion years

age of earth

nitrogen, nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen, hydrogen sulfide

chemicals that created small organic molecules, leading to the evolution of life

RNA

ribonucleic acid; the nucleic acid that was probably the first genetic material

protobiont

collections of chemicals trapped within membranes

DNA

deoxyribonucleic acid; more stable repository for genetic information because it is double-stranded

prokaryote

single-celled organism with no nuclei

Archaean Eon

3.9 to 3.5 billion years ago, when prokaryotes entered the picture

eons, eras, periods, epochs

divisions of time, from longest to shortest

cyanobacteria

a prokaryote that increased the amount of oxygen gas in the atmosphere through photosynthesis

eukaryotes

debuted 2.1 billion years ago

endosymbiosis

one prokaryote parasitized another prokaryote, or maybe just ate it but forgot to digest it

Cambrian Explosion

535 million years ago; major biological golden age when the diversity of all animal life on earth exploded

Ordovician Period

500 million years ago; plants, animal, and fungi started colonising land, probably as a strategy for escaping predation

Devonian Period

365 million years ago; tetrapods and arthropods showed up on land

Carboniferous Period

359-299 million years ago; forests were so dense and widespread that they made all our fossil fuels (35% oxygen in the atmosphere instead of the normal 21%)

Permian Period

299-251 million years ago; all the land masses of the world joined to form one giant continent (Pangaea)

gymnosperms

first plants with seeds like modern pines, spruces, and firs

archosaur

ancestor of dinosaurs and modern birds

Permian-Triassic Extinction Event

252 million years ago; 96% of all marine species and 76% of terrestrial vertebrate species bought the farm and the only known mass extinction of insects (57% of all taxonomic families and 83% of all genera became extinct); most significant extinction event on the planet

niche

combination of living and non-living resources they use to survive

Jurassic Period

199-145 million years ago; huge herbivorous dinosaurs roamed the earth with smaller, carnivorous dinosaurs

co-evolution

reciprocal evolutionary change in a set of interacting populations over time resulting from the interactions between those populations

Cretaceous–Paleogene Extinction Event

KT Extinction; 66 million years ago; mass extinction of three-quarters of the plant and animal species