Ch. 22

Front 1

species

Back 1

basic unit of evolution and taxonomy; two groups of organisms that differ from one another in one or more characteristics and do not hybridize extensively if they occur together in nature

Front 2

phylogenetic species concept

Back 2

Species are identified based on a unique combination of physical or molecular characteristics; using this may be difficult to determine the number of traits necessary to characterize individuals

Front 3

biological species concept

Back 3

group of individuals that can interbreed in nature and produce viable offspring would be considered to be a species

Front 4

What is the distinctive role of a specie in nature?

Back 4

niche

Front 5

speciation

Back 5

macroevolution leading to speciation is promoted by natural selection through isolating mechanisms, restriction of gene flow, character displacement, and impacting survivorship of hybrids

Front 6

subspecies/ecotypes

Back 6

two populations are geographically restricted groups of the same species, but display one or more traits that are somewhat different

Front 7

Describe Multiplication of Species in the Theory of Evolution

Back 7

Evolution produces new species through adaptive radiation (existence of groups of closely related species recently evolved from a common ancestor), the splitting of existing species into new ones.

Front 8

Adaptive radiation can produce

Back 8

several species cluster

Front 9

What does speciation involve?

Back 9

Evolution of reproductive barriers.
-Pre-Zygotic
-Post-Zygotic

Front 10

Pre-Zygotic

Back 10

before mating (no hybrid zygotes)
- mechanical isolation, temporal isolation, habitat isolation, behavioral isolation, gametic isolation

Front 11

Post-Zygotic

Back 11

after mating (infertility of mules)
- hybrid inviability, hybrid sterility, hybrid breakdown

Front 12

The underlying cause of specieation is?

Back 12

the accumulation of genetic changes that create enough differences so that it constitutes a unique species

Front 13

phylogenetic species concept

Back 13

Species are identified based on a unique combination of physical or molecular characteristics

Front 14

biological species concept

Back 14

A group of individuals that can interbreed in nature and produce viable offspring

Front 15

evolutionary species concept

Back 15

establish a lineage by examining DNA sequences of particular genes

Front 16

ecological species concept

Back 16

distinguishing species that are different from each other based on their use of resources

Front 17

mechanical isolation

Back 17

incompatibility of sexual reproductive organs or gamete fertilization

Front 18

temporal isolation

Back 18

variations in time related patterns prevents fertilization

Front 19

behavioral isolation

Back 19

variations in behavior prevents fertilization

Front 20

What are 2 modes of Speciation?

Back 20

1. Allopatric
2. Sympatric

Front 21

allopatric speciation

Back 21

geographically isolated populations result in the divergence of distinct species; most common speciation on islands

Front 22

First step to allopatric speciation?

Back 22

physical isolation of two population.

Front 23

sympatric speciation

Back 23

populations within a common area split into different species

Front 24

natural selection's role in speciation

Back 24

-strengthens isolating mechanisms
-restricts gene flow
-promotes character displacement
-affects survivorship of hybrids

Front 25

adaptive radiation

Back 25

can occur when a population becomes geographically isolated and several species develop into a wide array of descendent species

Front 26

speciation maintenance

Back 26

thru developmental differences, genetic blocks, somatic mutations, and/or structural modifications

Front 27

character displacement

Back 27

the tendency for characteristics to be more unalike between 2 sympatric populations (populations that are geographically close to one another) than between 2 allopatric populations (populations that are geographically farther away from each other

Front 28

convergent evolution

Back 28

where organisms not closely related evolve similar traits as a result of having to adapt to similar environments

Front 29

gradualism

Back 29

The model that assumes that evolution proceeds with slow successive change in a given evolutionary line

Front 30

prezygotic isolation

Back 30

prevention of formation of hybrid zygotes
1) ecological or temporal isolation
2) mechanical incompatibility
3) prevention of gamete fusion

Front 31

5 Postzygotic Barriers (reproductive isolation)

Back 31

1) habitat 2) temporal 3)behavioral 4) mechanical 5)gametic

Front 32

Polyploidy

Back 32

the condition of having three, four, or more sets of chromosomes instead of the two present in diploids; results in an organism that can mate with itself but not with either of its parents species

Front 33

is the most common mechanism for sympatric speciation and in plants,

Back 33

polyploidy

Front 34

mass extinctions

Back 34

- the 5 major mass extinctions were all followed by a rebound in species diversity
- major changes in the direction of evolution have often occurred after mass extinctions
- the 5 major extinctions were caused mainly by geological events and possibly from asteroid collisions
- rebound from the current 6th mass extinction may be slower than previous ones

Front 35

punctuated equilibrium

Back 35

Species evolve relatively quickly then exist essentially unchanged for most of their existence