Week 1 - Evolutionary Mechanisms

Question 1

3 goals of evolutionary biology are…

Answer 1

1. Unity of life
2. Diversity of life
3. Adaptation

Question 2

Why is history important in evolutionary biology?

Answer 2

History tries to answer important questions about the origin of life.

Question 3

What are nodes on an evolutionary tree?

Answer 3

They represent evolutionary branching or speciation events

Question 4

What does the branching tip represent?

Answer 4

Species that exist today

Question 5

What do hatch marks represent?

Answer 5

Homologous characteristics shared by all groups to the right of the mark

Question 6

What does the branch point represent?

Answer 6

Common ancestors

Question 7

What does homology mean?

Answer 7

Similarity from a common ancestor

Question 8

What does decent with modification mean?

Answer 8

Characteristics of species are modified, underlying similarity but function differently

Question 9

What are vestigial structures

Answer 9

Body parts that is reduced or impaired from its ancestral condition and no longer has a function

Question 10

Why does similar function not always mean homology?

Answer 10

Wings help stay aloft however may not be homologus because they aren’t passed down but arise from different developmental/genetic mechanisms

Question 11

What is convergent evolution

Answer 11

Independent evolution of similar features in species of different periods

Question 12

What is biogeography?

Answer 12

Similar species found on different continents

Question 13

What are the 4 testable postulate of natural selection?

Answer 13

1. Trait variation
2. Variation in survival /reproduction
3. Covariation between traits/fitness
4. Inheritance of trait variation

Question 14

What is phenotypic variation?

Answer 14

Important traits that vary between individuals
Amount of variation of a particular trait within a population

Question 15

What is phenotypic selection?

Answer 15

Individuals with specific characteristics produce more surviving offspring than others

Question 16

What is Anthropocene?.

Answer 16

Present era that is human dominated

Question 17

What is an individual

Answer 17

Physiological integrated unit that developed as a zygote made by sexual reproduction

Question 18

What is a population?

Answer 18

Group of individuals of a given species living in the same place

Question 19

Define gene pools

Answer 19

Entire collection of alleles in a population

Question 20

What is a species?

Answer 20

Collection of populations containing individuals that could potentially interbreed successfully

Question 21

What is a diploid genotype?

Answer 21

→ reshuffling of existing alleles
→ crossing over/ independent assortment

Question 22

What are new alleles?

Answer 22

New DNA sequences that enter a population through genetic exchange with a different population ( gene flow)

Question 23

Genetic polymorphism?

Answer 23

Presence of two or more variant form of a specific DNA sequence that can occur

Question 24

What is incomplete dominance?

Answer 24

Both genes are expressed together
Ex: red/white = pink

Question 25

Now can the environment effect phenotype?

Answer 25

pH of the soil

Question 26

What is the hardy-Weinberg equation?

Answer 26

p^2 + 2 Pq +q^1= 1

Question 27

What did Darwin purpose?

Answer 27

He proposed that life’s diversity arose from ancestral species through natural selection

Question 28

Who denied that evolution occurs

Answer 28

Cuvier - sudden catastrophic events in the past caused species to disappear from an areas

Question 29

Define adaptation

Answer 29

Inherited characteristics of an organism that enhances survival and reproduction

Question 30

What did Darwin propose about the origin of species

Answer 30

Over long periods of time, decent with modification produced rich diversity of life through natural selection

Question 31

What does and analogous mean?

Answer 31

Having characteristics that are similar because of convergent evolution, not homology

Question 32

What does the hardy-Weinberg equation explain?

Answer 32

The allele and genotype frequency will remain constant if the population is large, random mating, and mutation is negligible there is no gene flow and no natural selection

Question 33

Define genetic drift

Answer 33

Chance events cause unpredictable fluctuations in allele frequency from one generation to the next

Question 34

What is relative fitness?

Answer 34

Contribution an individual makes to the gene pool of the next generation

Question 35

What is sexual selection?

Answer 35

A form of selection in which individuals with certain inherited characteristics are more likely to reproduce than others

Question 36

What is balancing selection?

Answer 36

Natural selection that maintains two or more phenotypic forms in a population

Question 37

What is the founder effect?

Answer 37

Individuals become isolated from larger population and form new gene pools

Question 38

What is the bottle neck effect?

Answer 38

Size of a population is reduced because of natural disaster or humans ( less effect on large pop )

Question 39

Describe directional selection

Answer 39

Individuals at one end of the phenotypic range survive or reproduce more successfully

Question 40

Describe distributive selection

Answer 40

Individuals at both extremes of a phenotypic range survive or reproduce more successfully

Question 41

Describe stabilizing selection

Answer 41

Middle/intermediate phenotypes survive or reproduce more successfully

Question 42

What is intrasexual selection?

Answer 42

Competition between the same sex

Question 43

What is intersexual selection?

Answer 43

Individuals pick mates based on appearance or health

Question 44

What are frequency dependant selection

Answer 44

Fitness of a phenotype depends on now common it is

Question 45

What is the importance of heterozygotic advantage

Answer 45

Preserves variation in gene pool