Biology 6 Chapter 24 The Origin Of Species

Front 1

Speciation

Back 1

The process by which one species split into two or more species

Front 2

Micro Evolution

Back 2

Change in genetic makeup of a population from one generation to the next

Ex: Cross Breeding Dogs

Front 3

Macro Evolution

Back 3

change in the genetic makeup leading to the appearance of major evolutionary development

Ex: Development of wings and feathers

Front 4

Species

Back 4

population of Organisms capable of naturally breeding and producing fertile offspring

Front 5

Reproduction Isolation

Back 5

existence of biological factors (barriers) that impede members of two different species from producing fertile offspring

Ex: Liger

Front 6

Prezygotic Barriers

Back 6

factors that impede mating between species or hinder ova fertilization if members of different species attempt to mate

Ex: Blue footed Booties and red footed booties Dance ( mating ritual.

Front 7

Postzygotic Barriers

Back 7

Factors that prevent the hybrid zygote from development into a viable, fertile adult

Ex; Mules

Front 8

Limitations

Back 8

1.Difficult to uses reproductive isolation when only fossile are available

2. Doesn't apply to animal that reproduce asexually

3.Exceptions to Rule ( Organisms with distinct ecologices and morphologies where gene flow can sill occur

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Morphological Species

Back 9

Characterizes a species based on body shape and other structural features

Ex: Salamanders

Front 10

Plaeotological Species

Back 10

Based on Morphologies from fossil records only

Ex: Long Extinct Animals

Front 11

Ecological species

Back 11

characterizes a species based on its ecological niche; the sum of how members of one species interact with the ecosystem

Ex: Hyenas

Front 12

Phylogenetic species

Back 12

characterizes a species as the smallest group of individuals that share a common ancestor
a. Ex. salamanders

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Allopatric Speciation

Back 13

gene flow becomes interrupted when a population is divided into geographically isolated subpopulations
B. Geographical barriers include water, canyons, mountains, etc.

Front 14

Selecting agents

Back 14

any factors that affect the probability that certain traits will be passed on to the next generation

Front 15

Sympatric speciation

Back 15

formation of new species due to genetic change in the species from the original population; no geographic barrier
a. Ex. snails

Front 16

Polyploidy

Back 16

chromosomal alteration in which an organism possesses more than two complete sets of chromosomes

Front 17

Habitat differentiation

Back 17

a change in vegetation could alter the niche of members of a species living in the same habitat
Ex. North American apple maggot fly (native Hawthorne berries v. introduced apples)

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Sexual selection

Back 18

individuals with certain inherited characteristics are more likely to obtain mates with similar characteristics

a) Color change could alter the mate selection

b) Examples: African cichlids

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Hybrid zones

Back 19

region in which members of different, but similar species meet and mate, producing at least some offspring of mixed ancestry (hybrids)
a. Ex. European fire-bellied toad

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Reinforcement

Back 20

process in which natural selection strengthens prezygotic barriers to reproduction, thus reducing formation of hybrids

Front 21

Fusion

Back 21

process in which natural selection weakens prezygotic barrier to reproduction, thus reversing the process resulting in the formation of hybrids

Front 22

Stability

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prezygotic barriers to reproduction are neither strengthened nor weakened, allowing hybrids to persist

Front 23

Gradualism

Back 23

profound changes occur through the cumulative effect of slow, but continuous processes

Front 24

Punctuated equilibrium

Back 24

profound changes that occur in spurts between which are long periods of little or no evolutionary changes

Front 25

Adaptive radiation

Back 25

period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill vacant ecological niches in their new communities
a. Ex. Australian marsupials

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Convergent evolution

Back 26

pattern in which similar environmental pressures and natural selection produce similar adaptations in organisms from different evolutionary lineages

Ex. Echidna, hedgehog, tenrec