Biology Chapter 24

Front 1

Speciation

Back 1

process by which one species splits into 2+ species

Front 2

Microevolution

Back 2

evolutionary change below the species level; change in allele frequencies in a population over generations

Front 3

Macroevolution

Back 3

evolutionary change above the species level

Front 4

Species

Back 4

group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups

Front 5

Reproductive Isolation

Back 5

existence of biological factors that impede members of two species from producing viable, fertile offspring

Front 6

Hybrid

Back 6

offspring that results from mating of individuals from two different species or from two true-breeding varieties of the same species

Front 7

Describe the five prezygotic barriers that prevent inter-species mating.

Back 7

1. Habitat isolation - living in different parts of the same ecosystem

2. Temporal isolation - mating at different times (seasonal, diurnal/nocturnal, etc)

3. Behavioral isolation - courtship rituals are specific to each species

4. Mechanical isolation - mating may be attempted by the pieces don't line up

5. Gametic isolation - sperm from one species may not be able to fertilize the egg from another (unable to penetrate membrane, unable to survive, etc)

Front 8

Describe the three postzygotic barriers that prevent inter-species mating.

Back 8

1. Reduced hybrid viability - genes interact in ways that impair the hybrid's development

2. Reduced hybrid fertility - most hybrids are sterile due to failure in meiosis

3. Hybrid breakdown - breeding of hybrid to parent species lead to frail/sterile second generation hybrids

Front 9

Biological Species Concept

Back 9

concept that species are defined by what they can breed with to produce viable, fertile offspring

Front 10

Morphological Species Concept

Back 10

concept that species are defined by body shape and other structural features

Front 11

Ecological Species Concept

Back 11

concept that defines species in terms of its ecological niche, the sum of how members of the species interact with nonliving and living parts of their environment

Front 12

Phylogenic Species Concept

Back 12

concept that defines species as the smallest group of individuals that share a common ancestor, forming on brance on the tree of life

Front 13

Allopatric Speciation

Back 13

formation of new species in populations that are geographically isolated from one another

Front 14

Sympatric Speciation

Back 14

formation of a new species in populations that are not geographically isolated from one another

Front 15

The formation of new species in geographically isolated populations is called _____________ speciation.

Back 15

The formation of new species in geographically isolated populations is called allopatric speciation.

Front 16

The formation of new species in non-geographically isolated populations is called _____________ speciation.

Back 16

The formation of new species in non-geographically isolated populations is called sympatric speciation.

Front 17

Polyploidy

Back 17

chromosomal alteration that results in an organism having more than two complete chromosome sens (3n, 4n, etc.) as a result of accidents in meiosis or mitosis

Front 18

Autopolyploid

Back 18

individual with more than two chromosome sets all derived from a single species

Front 19

Allopolyploid

Back 19

fertile individual with more than two chromosome sets derived from two different species interbreeding and combining their chromosomes

Front 20

Hybrid Zone

Back 20

geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry

Front 21

Describe the three possible outcomes for a hybrid zone.

Back 21

1. Reinforcement - reproductive barriers strengthen and the hybrids gradually disappear

2. Fusion - reproductive barriers weaken and the two species fuse to form one

3. Stability - reproductive barriers remain constant and hybrids continue to be created

Front 22

Punctuated Equilibria

Back 22

in the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interupted by relatively brief periods of sudden change

Front 23

Adaptive Radiation

Back 23

rapid speciation under conditions in which there is little competition