Theme 4

Question 1

What Darwin didn’t know

Answer 1

Where variation came from (mutation)-he knew it existed, just not its origins.

Question 2

Variant, Variation, and Variability

Answer 2

Variant-version or type of a trait or allele (ex: different eye colours)
Variation-Degree of differences within a population (amount of individuals in a population with each eye colour)
Variability- Propensity of individuals to exhibit variants (likelihood of alleles, number of different eye colours possible.)

Question 3

Gene Flow

Answer 3

Dispersal; flow of genetic material from one population to another. Introduces new variants, can change frequencies of alleles in both populations.

Question 4

Genetic Drift

Answer 4

Happens by chance in small populations, due to individuals dying or not reproducing.

Question 5

Founder Effect

Answer 5

A few individual’s from a population start a new population with a different allele frequency than the original population. (ex: Pitcairn Islands, type O blood in central and South America, Polydactyl in Amish, Tay-Sachs in Quebecois).

Question 6

Bottleneck Effect

Answer 6

Large parent population-drastic reduction in population due to catastrophic events.

Question 7

Polymorphism and Variation

Answer 7

Two or more versions of a gene, different variations of traits that occur within a group-reduces inbreeding depression, homozygosity vs heterozygosity.

Question 8

Heterozygote Advantage (heterosis)

Answer 8

Sickle cell anaemia (resistance to malaria), balancing polymorphism.

Question 9

Hardy Weinberg Rules

Answer 9

No microevolutionary forces acting on population-can predict allele frequencies. No mutation, no migration, infinite individuals, equal reproductive success, no selection.

Question 10

Biological Species

Answer 10

Individuals that can reproduce (inbreed) and produce viable offspring.

Question 11

Typological Species

Answer 11

Individuals that have similar morphology are considered part of the same species.

Question 12

Ecological Species

Answer 12

Similar interactions with environment make them part of the same species.

Question 13

Reproductive isolation

Answer 13

Premating: Space, time, behaviour, function (genital incompatibility) Post Mating: gamete incompatibility, inviability, sterility

Question 14

Sympatic Speciation

Answer 14

Evolution of new ancestral species, while still maintaing the old species,while both continuing to inhabit the same geographical area.

Question 15

Allopatric Speciation

Answer 15

Biological populations of the same species become isolated from one another, preventing gene flow.

Question 16

Parapatric Speciation

Answer 16

Species are in close proximity, and occasionally interbreed (hybrid zone), but don’t produce viable offspring. Separated not by geographical things but by extreme habitat changes.

Question 17

Cladogenesis

Answer 17

Branching evolution-new species forms, splitting event.

Question 18

Anagenesis

Answer 18

Darwinian Gradualism/phyletic evolution. Small changes that continue to occur within a population or species.

Question 19

Cladistics

Answer 19

Shared evolutionary history. Based on field observation, morphology, DNA. Phylogenetics.

Question 20

Observable Traits

Answer 20

Ancestral-Traits are shared with common ancestor. Derived- New to lineage, appeared after splitting, not with common ancestor.

Question 21

Homologous Trait

Answer 21

Similar due to inheritance from a common ancestor (ex: Pentadactyle limbs in humans and whales)

Question 22

Analogous Trait (homoplasies)

Answer 22

Similar solutions to adapt to environment, species didn’t evolve from same lineages.

Question 23

Adaptive Radiation

Answer 23

Diversification of an evolving lineage (finches on Galapagos). Occurs due to new resources.

Question 24

Lemurs of Madagascar

Answer 24

Rafted to madagascar, 45 million years ago, madagascar has a climatic gradient with different biomes. Created 5 families of lemurs with over 110 species