Macroevolution

Question 1

What is microevolution?

Answer 1

It is change in the allele frequencies within and among populations within a species

Question 2

What is speciation?

Answer 2

It is how genetic changes within populations lead to reproductive isolation and new taxa

Question 3

What is macroevolution?

Answer 3

Speciation and broader changes in diversity at higher taxonomic levels, as well as the distribution of this over time and space

Question 4

Since macroevolution cannot be observed, through what process and how can we get information on macroevolutionary proccesses?

Answer 4

Through macroevolutionary influence, we rely on fossils, geology, molecular phylogenetics, and species distributions

Question 5

What is species turnover?

Answer 5

It is the extinction and replacement by new species

Question 6

in species turnover, what are the terms for the disappearance and replacement of species?

Answer 6

Disappearance - extinction

Replacement - origination

Question 7

What is the mathematical description of macroevolution?

Answer 7

It is the variation in turnover across time and space and clades

Question 8

What are the 4 patterns of fossil record of diversity over time observed?

Answer 8

1. Stasis
2. gradual change
3. rapid change/adaptive radiations
4. extinctions

Question 9

Define stasis?

Answer 9

It is a situation where evolutionary lineages persist for a long period of time without evolutionary change

Question 10

Is stasis common or uncommon?

Answer 10

Common

Question 11

Does stasis include local adaptations?

Answer 11

No

Question 12

What model of evolutionary change is outlined by slow, gradual changes in lineages?

Answer 12

Phyletic gradualism

Question 13

What are the two different ways new forms of morphologies can arise under phyletic gradualism?

Answer 13

Cladogenesis - splitting off of new taxa

Anagenesis - Gradual modification/lineage of one form into another

Question 14

Draw a tree of gradual evolution, and label where the two types of new form arisal would be found

Answer 14

Question 15

What is the contrast to phyletic gradualism?

Answer 15

Punctuated equilibria - short periods of stasis with some intervals of rapid morphological change

Question 16

Is the phyletic gradualism or punctuated equilibria theory better supported?

Answer 16

Punctuated equilibria

Question 17

What two process happen at the same time in a punctuation event?

Answer 17

Speciation and morphological change

Question 18

Draw a fossil record of gradualism vs punctuation

Answer 18

Question 19

What property of fossils make it hard to conclude which type of species change pattern is more common?

Answer 19

There are gaps in the fossil record

Question 20

What punctuated equilibrium event was the biggest emergence of organisms and included the radiation of body plans?

Answer 20

The cambrian explosion at the start of the cambrian period

Question 21

What is the criterion for a species to be extinct?

Answer 21

Every individual has died out

Question 22

What does the phrase “extinction is the rule not the exception” mean?

Answer 22

The vast majority of all species have gone extinct!

Question 23

What is background extinction?

Answer 23

It is the steady state of extinction over time due to probability

Question 24

What trophic level can we often only convey extinction to due to fossil record limitation?

Answer 24

Genera level

Question 25

When is extinction an exception?

Answer 25

Mass extinction - wholesale loss of many organism groups across the globe

Question 26

How can mass extinction rates compare to background extinction rates?

Answer 26

Mass extinction rates are much higher

Question 27

What are the 5 mass extinctions?

Answer 27

1. Ordovician - 445mya 2. Devonian - 340 mya 3. Permian - 250 mya 4. Triassic - 200 mya 5. K-T - 65 mya

Question 28

What were the highest rate and lowest rate mass extinctions?

Answer 28

Permian - highest 95% Devonian - lowest 70%

Question 29

What are the likely causes of the mass extinctions?

Answer 29

1. Ordovician - rapid cooling 2. Devonian - asteroid + more cooling 3. Permian - Volcanoes + methane and CO2 + desertification 4. Triassic - Methane and CO2 + global warming + deserts and heat weaves 5. K-T - asteroid + volcano + falling sea levels + ash cloud winter ## Footnote Abiotic and Biotic factors

Question 30

What metric do we have to determine if humans are cuasing mass extinction?

Answer 30

Human caused extinction rates are higher than background rates

Question 31

What is the formula for diversification?

Answer 31

D (t+1) = Dt + originations - extinctions

Question 32

What symbols do we use to denote the factors of diversification?

Answer 32

alpha - rate of origination omega - rate of extinction

Question 33

Where do diversification rates come from?

Answer 33

They are a function of alpha and omega

Question 34

What are the three things necessary for natural selection to act?

Answer 34

1. Variation 2. heritability 3. Differences in offspring production

Question 35

What is it called when natural selection is expanded to above the species level?

Answer 35

Species selection

Question 36

What are the two reasons why a taxonomic trend would be observed among taxa?

Answer 36

1. Parallel evolutionary change - all members go through a parallel change 2. Species will go extinct that do not match the trend