Evolution

Question 1

Homologous Structures

Answer 1

Body parts that resemble each other in different species

Evolved from common ancestor

Question 2

Analagous Structures

Answer 2

Resemble each other because evolved due to similar environments

Question 3

Darwin’s Argument For Natural Selection

Answer 3

Populations posses an enormous reproductive potential

Population sizes remain stable

Resources are limited

Much variation in heritable

Only the most fit individuals survive

Question 4

Stabilizing Selection

Answer 4

Common traits favoured

Question 5

Directional Selection

Answer 5

Favours one extreme

Question 6

Disruptive Selection/Diversifying Selection

Answer 6

Favours extreme traits, selection against common traits

Question 7

Sexual Dimorphism

Answer 7

Difference in appearance of males and females

Sexual selection is a form of disruptive selection

Question 8

Outbreeding

Answer 8

Mating with unrelated partners

Increases the possibility of mixing different alleles and creating new allele combinations

Question 9

Hybrid Vigor/ Heterosis

Answer 9

Superior quality of offspring resulting from crosses between 2 different inbred strains of plants

Superior hybrid quality results from a reduction of loci with deleterious homozygous recessive conditions and an increase in loci with heterozygote advantage

Question 10

Frequency-dependent selection/minor advantage

Answer 10

Least common phenotype has selective advantage

Will increase in frequency

Phenotypes alternate between low and high frequencies

Question 11

Gene Flow

Answer 11

Introduction or removal of alleles from the population when individuals leave (emigration) or enter (immigration) the population

Question 12

Genetic Drift

Answer 12

Random increase or decrease of alleles by chance

Greater effect in smaller populations

Question 13

Founder Effect

Answer 13

Allele frequencies in a group of migrating individuals are (by chance) not the same as their population of origin

Question 14

Bottleneck effect

Answer 14

□ Population undergoes a dramatic decrease in size

□ Resulting population becomes severely vulnerable to genetic drift

Question 15

Conditions For Genetic Equilibrium

Answer 15

All traits are selectively neutral (no natural selection)

Mutations do not occur

Population must be isolated from other populations (no gene flow)

Population is large (no genetic drift)

Mating is random

Question 16

Allopatric Speciation

Answer 16

Population divided by geographical barrier

Question 17

Sympatric Speciation

Answer 17

New species formed without geographical barrier

Question 18

Adaptive Radiation

Answer 18

Relatively rapid evolution of many species from a single ancestor

Question 19

Hybrid Inviability

Answer 19

Zygote can’t develop

Question 20

Hybrid Sterility

Answer 20

Hybrid is sterile

Question 21

Hybrid Breakdown

Answer 21

Hybrid produce produces offspring with reduced viability or fertility

Question 22

Divergent Evolution

Answer 22

2 or more species originate from a common ancestor and becomes increasingly different over time

May be a result of allopatric or sympatric speciation or by adaptive radiation

Question 23

Convergent evolution

Answer 23

2 unrelated species that share similar traits

analagous traits

Question 24

Parallel Evolution

Answer 24

2 related species or 2 related lineages that have made similar evolutionary changes after their divergence from a common ancestor

Question 25

Coevolution

Answer 25

Evolution of one species in response to new adaptations in another species

Question 26

Phyletic gradualism

Answer 26

Evolution occurs by the gradual accumulation of small changes Argues fossil record is incomplete

Question 27

Punctuated Equilibrium

Answer 27

Long periods of little/no evolution that is interrupted/punctuated by geologically short periods of rapid evolution Argues that absence of fossils revealing intermediate stages of evolution is considered data that confirms rapid evolutionary events

Question 28

Uniform Dispersion

Answer 28

Individuals spaced evenly i.e. Plants secrete toxins to inhibit growth of nearby individuals Animal species stake out and defend territories

Question 29

Commensalism

Answer 29

One party benefits, no effect on other party Form of symbiosis

Question 30

Allelopathy

Answer 30

Production of biochemicals by an organism that influences the growth, survival, and reproduction of other organisms Form of interference competition

Question 31

Interference Competition

Answer 31

Occurs directly between individuals via aggression Other individuals are prevented form physically establishing themselves on a shared habitat

Question 32

Exploitation Competition

Answer 32

Occurs indirectly through depletion of a common resource i.e. Lions and cheetahs both hunt for gazelles If lions eat all the gazelles, will affect cheetahs

Question 33

Apparent Competition

Answer 33

Occurs when 2 species are preyed upon by the same predator i.e. Spider and beetles hunted by owls If spider population increases, owl population will increase, and will hunt more beetles

Question 34

Intraspecific Competition

Answer 34

Types of competition that occurs between members of the same species

Question 35

Ecological Succession

Answer 35

Predictable process of ecosystems changing and developing over time Occurs in a new habitat or after a disturbance

Question 36

Primary Succession

Answer 36

Occurs after a large disturbance in an area that has never supported live Begins with pioneer species (lichen, fungi, algae)

Question 37

Order of Colonization

Answer 37

Pioneer species---> thin soil---> vascular plants---> larger plants---> animals

Question 38

Climax Community

Answer 38

Community that has reached steady state

Question 39

Secondary Succession

Answer 39

Has supported life previously, but has had destruction following a disturbance Similar pattern of colonization as primary succession, but begins with grasses and shrubs

Question 40

Keystone Species

Answer 40

Maintains ecological balance despite low abundance (i.e. predator)

Question 41

Anagenesis

Answer 41

Differentiation process which causes one species to evolve into a new one

Question 42

Cladogenesis

Answer 42

Speciation event allowing for the introduction of novel species from an ancestor

Question 43

Opportunistic Relationship

Answer 43

Bacteria, virus, protozoan or fungus takes advantage of opportunities to cause disease

Question 44

Parasitism

Answer 44

One organism benefits but the other is harmed

Question 45

Cryptic Colouration

Answer 45

Organism using colouring to avoid detection by its predators

Question 46

Batesian Mimicry

Answer 46

Prey animal mimics a warning signal of an animal that possesses strong defenses

Question 47

Molecular Mimicry

Answer 47

Structural, functional, or immunological similarities shared between macromolecules found on infectious pathogens and in host tissues

Question 48

Mullerian mimicry

Answer 48

2 species that are equally unpalatable evolve to look like each other Predator learns to avoid one, will avoid both