Theme 1 Phylogeny and Evolution

Question 1

What are the 3 main components of Biodiversity?

Answer 1

1. Genetic Diversity
2. Species Diversity
3. Ecosystem Diversity

Question 2

What are the 4 main threats to biodiversity?

Answer 2

1.Habitat loss
2. Invasive species
3.Overexploitation
4. Climate Change

Question 3

Provisioning Services

Answer 3

Raw resources ie food, medicine, fibres, fuels

Question 4

Regulating Services

Answer 4

Benefits beyond raw resources ie pollination, pest control, purification of water and air

Question 5

What are ecosystem Supporting Services?

Answer 5

Ecosystem services critical to the survival of the biosphere ie habitats, cycling of nutrients and biomass and production of oxygen

Question 6

Inductive Reasoning

Answer 6

Used to make generalizations from specific observations and propose hypotheses

Question 7

What is Deductive Reasoning?

Answer 7

Used to make specific predictions to test hypotheses

Question 8

Hypothesis vs Theory

Answer 8

Hypotheses: narrow-scoped, tentative, are explanatory
Theories: Broad-scoped, strongly supported by large body of evidence, often leads to new testable hypotheses ie. predictive

Question 9

How do we test different hypotheses?

Answer 9

The scientific method

Question 10

Taxonomy

Answer 10

Scienitific discipline of naming and classifying organisms

Question 11

Systematics

Answer 11

A system and practice of classifying organisms based on evolutionary history

Question 12

What are the main principles of Natural Selection?

Answer 12

1. There are more offspring produced than can possibly survive in the environment, which will cause competition
2. There is inheritable variation within a population
3. Successful traits will accumulate over many generations (evolution)

Question 13

List the main pieces of evidence which support Evolutionary Theory

Answer 13

1. Direct observation (often with organisms with short lifespans)
2. Molecular and morphological homologies (similarities)
3. Fossil Records
4. Biogeography (study of organisms based on geographic distribution)

Question 14

What is the phenotype?

Answer 14

Interaction of the genotype and environmental factors

Question 15

List the 2 main sources of genetic variation

Answer 15

1. Mutations (UV radiation, point mutations, etc)
2. Meiosis causing reshuffling of homologous chromosomes

Question 16

Factors that affect allele frequency and whether they’re adaptive or not

Answer 16

1. Natural Selection (adaptive)
2. Genetic Drift (e.g bottleneck or founder effect)
3. Gene Flow

Question 17

What is a phylogeny?

Answer 17

A relationship between organisms sharing a common ancestor

It is also a hypothesis

Question 18

What is a polytomy?

Answer 18

A region on a phylogeny with 2+ sister lineages
-represents unresolved divergence patterns
-also represents rapid speciation

Question 19

What are the three types of phyletic groups?

Answer 19

1. mono*phyletic group
2. paraphyletic group
3. polyphyletic group

red- polypyletic
blue-paraphyletic
yellow-monophyletic/clade

Question 20

Difference between synapomorphy and symplesiomorphy

Answer 20

synapormorphy: a derived character shared by taxa and their last (most recent) common ancestory
symplesiomorphy: ancestral character shared by taxa, from an ancestory older than the most recent

Note these terms are relative, a character can be both

Question 21

What are characters?

Answer 21

Anatomical, physiol, molecular features

Question 22

Homology vs analogy

Answer 22

Homologous- shared evolutionary history
analogous -similar function but evolved sepparately

Question 23

Which traits are used to construct a phyolgeny?

Answer 23

Only homologous, not analogous

duhh

Question 24

Which factors, that alter allele frequency are more common in smaller populations?

Answer 24

Genetic drift - less gene carriers = higher chance of losing gene

Question 25

What are the selective processes by which multiple alleles are actively maintained in a gene pool?

Answer 25

Balancing Selection:
1. heterozygote advantage
2. frequency depedendent selection

Question 26

What is frequency dependent selection?

Answer 26

The fitness of a phenotype depends on it’s frequency, a form of balancing selection,

e.g a blue fish sticks out if all the fish are gray and few are blue

Question 27

What is Heterozygote advantage?

Answer 27

A heterzyogous genotype has an advantage over homozygous genotypes

Question 28

List several ways in which a population maintains genetic variation

Answer 28

1. mutation
2. recombination
3. indepdent assortment
4. random mating
5. gene flow
6. natural slelection
7. recessive alleles hidden (skip a generation, natural selection doesn’t act)
8. balancing selection

Question 29

What keeps species distinct under Biological Science Concept definition of species?

Answer 29

Pre-zygotic Barriers and post-zygotic barriers

Question 30

List the following from broadest to narrowest
1.Macroevolution
2.microevolution
3.speciation

Answer 30

Most broad: macroevolution (above species level)
Speciation
Most Narrow: Microevolution (changes in allele frequency at population level)

Question 31

What is the BSC definition of species?

Answer 31

A group of potentially interbreeding individuals capable of producing viable fertile offspring

Question 32

List Other Definitions of species

Answer 32

1.Ecological (similarity of niches defines species)
2.Morphological
3.Phylogentic (smallest group of individuals on phylogenetic tree)

Question 33

Define Prezygotic Barriers

Answer 33

Barriers that prevent mating or completion of mating, or of fertilization

Question 34

List the prezygotic reproductive barriers

Answer 34

1.Habitat isolation (rarely encounter each other because of different habitats, not necessarily physical barriers)
2.Temporal Isolation (mate at different times ie, season,day/night)
3.Behavior Isolation (different mating rituals, etc)
4.Mechanical Isolation (anatomically incompatability in mating)
5. Gametic isolation (gametes are genetically or chemically incompatible)

Question 35

Define Post-zygotic barriers

Answer 35

Barriers preventing a hybrid zygote from becoming a fertile, viable adult

Question 36

List the postzygotic barriers

Answer 36

1. Reduced hybrid viability (impair survival or development)
2. Reduced hybrid fertility
3. Hybrid breakdown (first generation is viable and fertile, next generation is feeble and sterile)

Question 37

Define Allopatric speciation

Answer 37

-gene flow interrupted between geographically isolated populations (physical barrier results in speciation), can result in the evolution of new species from an ancestral species

Responsible for majority of speciation events

Question 38

How does sympatic speciation occur?

Answer 38

When reproductive barriers (through natural selection) isolates a subset of a population from the parent species

Question 39

What are the three ways in which allele frequencies may be changed, representing microevolution?

Answer 39

1. Natural Selection
2. Genetic drift (random, chance events, E.g bottleneck effect)
3. Gene flow

Question 40

What are the three types of natural selection?

Answer 40

1. Stabilizing (favours the mean phenotype, causes little evolutionary change)
2. Disruptive (favour extremes of phenotypic range)
3. Directional (select for phenotypes different from the mean)