Speciation

Question 1

Speciation

Answer 1

States that no matter how extensive the phenotypic variation, individuals remain members of the same species as long as their morphology (forms/structures), physiology (functions), and behaviour allow them to interbreed and produce fertile offspring.

Question 2

Transformation

Answer 2

one species evolves into another.
where a species splits into two or more distinct species.

Question 3

Divergence

Answer 3

a parent species evolves into more than one other species.
single species evolves into a different species over time without branching or splitting.

Question 4

Geographic Barriers → Allopatric Speciation

Answer 4

Geographic barriers are physical features that separate populations and prevent them from interbreeding.

is a form of speciation that occurs when biological populations of the same species become geographically isolated from each other to an extent that prevents or interferes with genetic interchange.

-Mountains (including volcanic eruptions), rivers, canyons, glaciers
-Islands that break off mainland as continents drift
-Rerouting water flow/creating dams, building highways/city construction
-Moving species to different parts of the world (eg. zoos and animal reserves)

Question 5

Reproductive isolation

Answer 5

when species within populations no longer mate to produce fertile offspring. When reproduction fails, gene flow is completely restricted and populations may then be categorized as different species.

occurs when populations of the same species that live in the same geographic area evolve into distinct species.

Question 6

Gene flow

Answer 6

the introduction of new alleles from one population to another by the interbreeding of their members and results in increased genetic variation within that population.

Question 7

Prezygotic

Answer 7

Some barriers occur before mating and are deemed “Prezygotic” (before the zygote [egg & sperm fusion]).
Prevent mating or fertilization between species.

Question 8

Postzygotic

Answer 8

Some barriers occur after mating and are deemed “Postzygotic” (prevents fertile offspring)
Prevent hybrid offspring from developing into a viable, fertile adult.

Question 9

Habitat

Answer 9

they live in different locations, areas, spaces. Species live and breed in different habitats.

Question 10

Behavioural

Answer 10

songs, calls, or dances are not shared or recognized. Differences in mating behaviors prevent interbreeding.

Question 11

Temporal

Answer 11

breeding or activity at different times of day/season/year. Species breed at different times.

Question 12

Mechanical

Answer 12

structures are not compatible. Physical differences prevent successful mating.

Question 13

Gametic

Answer 13

sperm is not able to penetrate the egg (anatomically incompatible). perm and egg are incompatible.

Question 14

Zygote Mortality

Answer 14

when an egg is fertilized, but the zygote or embryo dies

Question 15

Hybrid Inviability

Answer 15

Hybrid offspring do not develop properly or die early.

first generation hybrid offspring is born, but shows low fitness it may not make it to the age of being able to reproduce. Hybrid offspring do not develop properly or die early.

Question 16

Hybrid Sterility

Answer 16

Hybrid offspring are sterile and cannot reproduce.

when the hybrid offspring grows to breeding age, but is incapable of gamete formation.
Eg. mules and zebroids are competitive organisms, but are sterile due to parental chromosomal differences.