Evolutionary Genetics Chapter 28

Front 1

What is the definition of a species?

Back 1

Reproductively isolated which allows selective pressures and variability. A group of individuals that occupy the same space at the same time

Front 2

Typological species

Back 2

species conform to a set of fixed properties (phenetics). "If you fit into this category you are this species"

Front 3

Morphological species

Back 3

species vary by morphological characteristics, such as flowers structure (Linnaean theory- Could distinguish species based on morphology. Certain number of anters, color, petals, ect.)

Front 4

Evolutionary species

Back 4

a group of organisms that share an ancestor and maintains its integrity through time and space (Darwinian theory)

Front 5

Phylogenetic species

Back 5

- organisms that maintain their integrity through space and time, but differs from evolutionary species in that the common ancestor goes extinct as new species evolve (cladistics)

Front 6

Recognition species

Back 6

organisms that share mating and reproductive systems

Front 7

Mate recognition species

Back 7

organisms that recognize each other as potential mates (pre-mating reproductive isolation). Allows a member of a species to recognize the same species and the opposite sex of that same species.

Front 8

Ecological species

Back 8

a population of individuals adapted to a particular niche in the environment

Front 9

Genetic species

Back 9

based on DNA similarities between populations (DNA-DNA hybridization)

Front 10

Evolutionary significant unit

Back 10

a population of organisms considered unique for the purpose of conservation. Example; panthers- deemed worthy of conserving because they are an Apex predator

Front 11

a new species is defined as a group of interbreeding or potentially interbreeding population that is reproductively capable and reproductively isolated in nature from all other such groups. Thus, species can be considered as a distinctive gene pools. Speciation occurs when one gene pool divides into two or more separate gene pools according to what?

Back 11

According to the biological species concept

Front 12

The biological species concept is problematic for use with most prokaryotes why?

Back 12

which do not reproduce sexually and cannot interbreed

Front 13

The biological species concept is problematic for many plants and birds

Back 13

where populations may be able to interbreed but rarely do in nature

Front 14

What two plant individuals can you place together they do produce viable offspring . What about animals?

Back 14

Boltonia asteroides; boltonia decurrens; You can cross zebriods (zebra, donkey)
Liger and tion (differences based on which is the mother and which is the father)
Wholphin (whale and a dolphin)
Grolar bear (grizzly and polar bears)
Beefalo (cow and buffalo)

Front 15

Speciation can occur by

Back 15

transformation or by splitting gene pools

Front 16

A species can do the following

Back 16

can remain static, undergo phyletic evolution to become a new species (anagenesis), or undergo cladogenesis to give rise to 2 distinct and independent daughter species

Front 17

Species change is a result of

Back 17

natural selection. Under certain conditions, populations that could interbreed at one time may lose that capability, and thus they are defined as distinct species.

Front 18

Although Wallace and Darwin explain how evolution occurs,

Back 18

they could not explain the origin of variation or how this variation is transmitted to offspring

Front 19

What is the source of genetic variation?

Back 19

Mutation

Front 20

What mechanisms allows for differences in transmission of this variation?

Back 20

Meisosis, gametogenesis, independent assortment

Front 21

Although most populations exhibit phenotypic similarities among individuals, most usually contain a high degree of heterozygosity and genetic diversity there are exception. What are they?

Back 21

Severe founder or bottleneck affect

Front 22

What is is one method of detecting underlying genetic variation because only a phenotype with genetic variation will respond to selection

Back 22

Artificial selection

Front 23

, its been estimated that as many as 2/3 of all loci in a population exhibit genetic variation and that up to 1/3 of the loci in any individual are heterozygous based on

Back 23

protein electophoresis

Front 24

Allozymes

Back 24

are electrophoretically distinct proteins produced by different alleles and they are different and can be separated electrophoretically by charge or size they are allozymes

Front 25

The most common mutation is cystic fibrosis is

Back 25

Delta 508; This is telling us that even for a single gene there is quite a bit of variability from individual to individual

Front 26

The neutral theory of molecular evolution suggests

Back 26

that most genetic variation results from accumulation of neutral mutations (thus, not subject to natural selection) neutral mutations would be a function of mutation rates and genetic drift

Front 27

Natural selection suggest

Back 27

genetic variation is maintained because it provides a selective advantage and give a diversity.

Front 28

Why is it good to have a diverse population?

Back 28

The more individuals you have the higher the diversity of neutral mutations
It is good to have a very diverse gene pool and you can accomplish that by maintaining a large population size. If you have a small population size, you can have randomly fixed or lost alleles.

Front 29

The genetic structure of a species can vary across space and time. Give an example of a species

Back 29

D. psedoobsscura. These populations also exhibit seasonal genetic variations within a single population

Front 30

What happens if you limit one species that does better in one temperature over the other?

Back 30

you need both populations to maintain the species. If both populations did well in their environment (war m and cool) over time the alleles can be fixed in their population and divergence may occur.

Front 31

Reduced gene flow, selection, and genetic drift can lead to?

Back 31

speciation

Front 32

When gene flow between populations is reduced or absent what happens

Back 32

the populations may divergeto the point that members of 1 population may not be able to interbreed with members of other. When the 2 populations become reproductively isolated, they have become different species.

Front 33

Prezygotic mechanisms can happen in many ways

Back 33

Geographic – the populations live in the same region but occupy different habits; our species is fine but it doesn’t work in plant speices, you even have differences in occupying different nitches

Seasonal- one population is adapted to its environment and another population reproduce in

Behavioral- species concept that are able to recognize mates, they may have morphological differences, so the reproductive capability is there but the recognizition that is a mate is lost

Mechanical- plant example if the plant morphology is different they may not be recognized by the pollinator.

Physiology – corn is intolerant to self-pollination; the gametes fail to survive in alien reproductive tracts

Front 34

Post zygotic mechanisms can happen in many ways

Back 34

Hybrid non viability or weakness- they may be able to form the embryo but then it gets aborted

Developmental hybrid sterility- gonads develop abnormally or meiosis breaks down before completion
Hybrid sterility- hybrids are sterile because of abnormal segregation into gametes of whole chromosomes, chromosome segments, or combination of genes.

Front 35

The length of time required for speciation can be very long or surprisingly short. An example of a very rapid speciation is the

Back 35

cichlids in Lake Victoria

Front 36

fast speciation is possible through the mechanisms of polyploidy, which is important in plant evolution. Give two examples

Back 36

brassica and potatoe

Front 37

Because speciation is associated with genetic divergence, the genetic differences among species can be used to

Back 37

reconstruct their evolutionary histories