Evolution exam 2 (1)

Phylogenetic Tree

Three ways to measure time

Relative time

Absolute time

Base pair substitutions

Phylogenetics

Work to find branch distances + orders

Phenetics

Overall similarity (distance)

• start w/ similar taxa

Mosaic Evolution

Common trait that is shown in various ways through species

• Ex) Ability to walk

Cladistics

Shared derived characteristics

Monophyletic Group

From 1 ancestor (in one group)

Homology

Shared ancestor + trait (derived)

5 Fingers/Digits

Homology

Plesiomorphy

Derived

Symplesiomorphy

Synapmorphy

Plesiomorphies

Ancestral to cladist

Synapmorphies

Shared derived !

Symplesiomorphies

Shared ancestral (too narrow)

Outgroup Comparison

Where to root tree

Preserved ancestral trait

Serves as comparison point from ancestral to now

Bootstrapping

Distance Matrix

Find similarities → pairwise

fill in half the table

count the differences between each species by the site → fill in the differences

Smaller number = more similar → put those together

Then make new trees until you finish

Paraphyletic

Only SOME descendants of the total

Monophyletic

One clade

One whole group

One shared ancestor for a group

Polyphyletic

In multiple groups → can be in or out of the main group (where majority is)

If its all scattered

The different time eras

Precambrian

Paleozoic

Mesozoic

Cenozoic

Pre Cambian

87% of time

tiny molecules, single cell (prokaryotes + microbes)

eukaryotes began (1.8 bya)

multicellular eukaryotes (1.2 bya)

Very Quiet

Which era of time occurred longest ? (87%)

Pre Cambian

Origin of Eukaryotes

They ate each other (absorbed) → adapted

Mitochondria comes from bacteria !

What started the Paleozoic era?

Cambrian explosion

541 mya

Paleozoic

Evolution of fish → tetrapods → amniotes

Colonization of land by plants + arthropods

Permian Extinction ( 252 mya)

End-Permian Extinction

252 mya

BIGGEST MASS EXTINCTION

96% of marine life + 70% land species went extinct

Origin of major animal groups

during Paleozoic (led to mezo)

Mesozoic

(Cretaceous, Jurassic, Triasic)

Dinosaurs + birds

major tectonic changes (pangea)

evolution of flowering plans (gymnosperms + angiosperms)

First mammals evolved

K-Pg Extinction

K-Pg Extinction

End of Mesozoic (specifically Cretaceous)

Paleogene extinction

the asteroid that killed most land dinosaurs

Cenozoic

Current Era → Mammals flourishing

Rise of primates + early humans (VERY late on, last 1%)

Ice Age + development of modern ecosystems

• world cooling

• everything frozen

Pre Cambrian (time)

538 mya

Paleozoic (time)

541 million to 251.9 mya

Mezosoic (time)

252 million to 66 mya

Cenozoic (time)

66 mya to now

When did life originate?

3.5 billion years ago (bya)

Incomplete lineage sorting

Barrier for gene flow and speciation

Gradual extinction

Darwin's prediction ( natural selection )

Adaptive radiation

One species becomes several who live in different ways (colonization, mass extinction, new niches)

Convergent evolution

Species developing the same trait due to environmental pressures (similar)

Analogous

Same function , but different origins (wings and the ability to fly does not mean they're related)

Red Queen Hypothesis

Species must continually adapt to keep up with each other

(coevolution)

Coevolution

2 or more species evolve in response to evolutionary changes in EACH OTHER

• they are ecologically close

• usually predator/prey

• host/parasite

• mutualists (plants/pollinators)

Punctuated Equilibrium

Long time of equilibrium that has periodic bursts of evolutionary growth

Hox Genes

Genes that regulate the anterior-posterior body axis in animals

Developmental Genes

Hox

ABC model → Glower Development

Vicariance

Separation of a continually distributed population/species into multiple due to a geographical /ecological barrier

Dispersal

They expand the range of land (literally disperses)

Malpighia fish

3 types of dispersal

1. Water

2. Wind

3. Birds (very weak)

What type of evolution did bilateral symmetry get?

analogous, evolved independently in each species

How to read tree

From the most recent and closely related 2, then slowly go to the past