Unit Review

Miller Urey experiment

replicated chem of early Earth “primordial soup” Inorganic molecules -> important organic molecules

Gene First Hypothesis

origin of life started with self-replicating RNA

- Evolutionary forces

- RNA organisms later utilized other macromolecules

- DNA later became base for genetic code

Metabolism first hypothesi

self-sustaining metabolic reaction formed first
- Energy and components provided by the environment (Hydrothermal vents)
- Other components came later to create more complex chem networks
- Many metabolic reactions are cyclic -> self-sustaining, influence of evolution

Extraterrestrial Hypothesis

-life came from space (very questionable)
- Important components of life came from space (less questionable)

Homology

features that are the same/ similar due to common ancestry

- Many specialized anatomical parts are just modifications of parts in other species

Homoplasy

features that are the same/ similar not because of common ancestry

- Convergent evolution!

Embryology

the study of embryos and their development, providing insights into evolutionary relationships.

Genetic information can be homologous – evolutionary history -> genetic similarity

Pangea

ancient supercontinent

• broke up during jurassic

Gondwana

Southern half

Laurasia

northern half

Geographic distribution of organisms

refers to how species and populations are spread across different regions and habitats, influenced by historical events like continental drift.

Fossil record

largely incomplete

- Changes a lot

- No mammals (Jurassic)

- No angiosperms (Triassic)

- No gymnosperms (Carboniferous)

- No fish (Cambrian)

Phanerozoic Eon

present - 570 mya

Paleozoic Era
Mesozoic Era
Cenzoic Era

Cenzoic Era

present - 65.5 MYA

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Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Holocene

Mezoic Era

65.5 - 245 MYA

Triassic, Jurrassic, Cretaceous

Palezoic Era

245-570 MYA

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Cambrian, Ordovician, Silurian, Devonian, Carboniferous (Mississippian and Pennsylvanian),
Permian

Proterzoic Eon

570-2500 MYA

Eukaryotes appear (and multiceulluar organisms appear)

Oxygen levels increase

Pre-Cambrian

Archean —> 2nd Oldest Eon; prokaryotes appear

Hadean —> Oldest Eon; no life on Earth

Cambrian

Cambrian explosion (rapid diversification of multicellular eukaryotes), arthropods most dominant animal (some ventured on land)

Ordovician

Ordovician radiation (diversification), vertebrates, appearance of jawless fishes

Silurian

appearance of bony (jaw) fish, first vascular plants appear (adapted to live on land), first fully terrestrial animals appear (Pneumodesmus)

Devonian

“age of fish”, rapid diversification of fish, fish become dominant, entire evolution of land walking tetrapod from jawed fish occurs

Carboniferous

Mississippian and Pennsylvanian

amphibians diversify, first amniotes appear, lycopsid forests grow out of control, oxygen levels rise, giant terrestrial arthropods (centipedes)

Permian

gymnosperms appear and replace lycopsid and fern trees, synapsids become dominant (tetrapod with 1 hole in skull), first dinosaurs, ends with PT extinction (95% of life dies)

Triassic

synapsids, crocs and dinosaurs compete for control after PT extinction (dinos win!), mammals appear, dinosaurs diversify

Jurassic

gymnosperms dominant, first angiosperms appear, first birds appear, dinosaurs get big, Pangea splits

Cretaceous

angiosperms become more common, some dinosaurs go extinct, new dinosaur groups appear, ends with KT or KPg extinction event (65% of all life dies and all non-avian dinosaurs die)

Paleocene

angiosperms expanding, forests rapid growth in absence of dinosaurs, mammals become dominant and grow larger

Eocene

very warm, N/S poles covered in forests, ungulates (hooved mammals) prominent, whales diversify, grass appears, ends with Oi1 event (major cooling)

Oligocene

Antarctica covered in ice, modern family of mammals present (Hominids and Apes), angiosperms more dominant, grass spreads away from waterside

Miocene

grasslands appear, grazing animals more common, Hominins (bipedal apes) appear, Earth warms then cools again

Pliocene

Australopithecus appears, “Great American Interchange” Panama rose from the sea and N/S America connected for the first time since Cretaceous

Pleistocene

“Ice Age”, modern humans appear, Megafauna extinction of mammoths, mastodon, glyptodon, and giant ground sloths)

Holocene

Modern day, glacial retreat, worldwide expansion of human population, includes all recorded human history

Phylogeny/Cladogram

shows evolutionary relationships

Leaves

selected taxa

Root

point where the tree connects back to the tree of life

Node

hypothetical common ancestors (no organisms on nodes

Speciation

1 species turns into 2 or more species

Allopatric speciation

new species appear in different areas → vicariance (areas move) or migration (species move)

Sympatric speciation

new species appear in the same areas —> disruptive selection

Species

a group of organisms that can interbreed and create viable, fertile offspring

Prezygotic barrier

prevents mating

Postzyogtic barrier

prevents viable, fertile offpsirng

Extinction

when all members of a species die off

Mass Extinction

when a large % of Earth’s species dies off at once

Adaptive radiation

rapid rate of speciation —> ecologial/morphlogicla diversity

Gradualism

slow changes in speciation ex. Sharks

Punctuated equilibrium

fast changes in speciation

Speciation

extinction equilibrium - a constant state of biological diversity when speciation rate = extinction rate

Pre-Caldistic Linnaaean classification System

organisms grouped into hierarchies
Kingdom, phylum, class, order, genus, species

Binomial Nomenclature

scientific name (genus name + species epithet)
doesn’t show how closely related organisms are

Taxonomy

process of naming and calssifiying organisms based on phylogeny

Monophyletic group

consists of 1 common ancestor and all the descendants

Paraphyletic Group

consists of 1 common ancestor but not all descendants

Polyphyletic group

consists of distantly realted organisms

Synapomorphies

shared derived characters (informative)

Plesiomorphies

shared ancestral (old) characters (uninformative)

Autapomorphies

unshared derived characters (uninformative)

Outgroup

distnatly related group that is used to distinguish synapomorphies from plesiomorphies

Parsimonious Analysis

least number of assumptions or evolutionary steps

Goal: maxmimize homology, minimize homoplasy

Polytomy

when there is more than one most parsimonious result

Hard polytomy

results from evolutionary processess (real)

Soft polytomy

results from bad data (not real)

Apomorphy-based clade

the ancestor to evolve a synpomorphy and all its descendants

Node-based clade

the most recent common ancestor of two taxa and all its descendants (when both taxa living —> crown clade)

Stem-based clade

all organisms more closley related to one taxa than anotherD

Deltran

delayed; priortized convergent evolution

Acctran

accelerated; priortizes losses/reversals