Slu -- Biology 106 Exam 2

Front 1

evolution

Back 1

change in allelic frequencies within a population over time

Front 2

Evolution acts on _______s, not ________s

Back 2

populations; individuals

Front 3

descent with modification

Back 3

changes over time produced modern species from ancestral species

Front 4

vestigial trait

Back 4

a reduced or incompletely
developed structure in an organism that has no
function or reduced function, but is clearly similar
to functioning organs or structures in closely
related species

Front 5

structural homology

Back 5

similarities in adult morphologies

Front 6

When does speciation occur?

Back 6

occurs when populations of the same species become genetically isolated by lack of gene flow and then diverge from each other due to natural selection, genetic drift, or mutation

Front 7

What constitutes a distinct species?

Back 7

populations that are reproductively isolated from each other, have
distinct morphological characteristics, or form
independent branches on a phylogenetic tree

Front 8

biological species concept

Back 8

populations are evolutionarily independent if they do not interbreed

Front 9

prezygotic factor

Back 9

a mechanism that prevents mating or fertilization

Front 10

postzygotic factor

Back 10

a mechanism that prevents development or viable or fertile adults (i.e. ligers)

Front 11

Types of prezygotic factors

Back 11

1) Habitat Isolation
2)Temporal Isolation (different breeding times)
3) Behavioral
4) Morphological
5) Gametic (sperm-egg incompatibility)

Front 12

Types of postzygotic factors

Back 12

1) Hybrid zygote inviability
2) Hybrid sterility
3) Hybrid “breakdown”
•Genetic incompatibility with self or parents
•Behavior inappropiate to be recognized by either
parent
•Is ecologically intermediate between parent species

Front 13

allopatric speciation

Back 13

speciation occurs in geographic isolation

Front 14

sympatric speciation

Back 14

speciation within a panmictic
population

Front 15

founder effect

Back 15

a special kind of allopatric
speciation in a small isolated population on the edge of a species range

Front 16

parapatric

Back 16

speciation in adjacent populations with gene flow

Front 17

polyploid

Back 17

an organism with multiple sets of chromosomes

Front 18

autopolyploid

Back 18

produced because of a mutation that causes a doubling of chromosome number

Front 19

allopolyploid

Back 19

individuals created when
parents that belong to different species produce an offspring in which chromosome number
doubles

Front 20

Aneuploidy

Back 20

Duplication or loss of an individual chromosome

Front 21

Paralogues

Back 21

two genes within an organism that have arisen from the duplication of a single gene in an ancestor

Front 22

Orthologues

Back 22

reflects conservation of a single gene from a common ancestor

Front 23

Horizontal gene transfer (HGT)

Back 23

Genes hitchhike from other species