Questions.
1.
Distinguish between anagenesis and cladogenesis.

Anagenesis is the transformation of an unbranched lineage of organisms, sometimes it is so different from the ancestral population that they put them as a new species. Cladogenesis is the budding of one or more new species from a parent species that continues to exist.
2.
Define biological species according to Ernest Mayr.

Ernst Mayr thought biological species was when a population or group of populations whose members have the potential to interbreed w/ one another in nature and to produce fertile offspring but they couldn’t produce fertile offspring w/ members of others species.
3.
Distinguish between prezygotic and postzygotic isolating mechanisms.

Prezygotic barriers (before the zygote) block fertilization from occurring while in postzygotic barriers (after the zygote) prevents the hybrid zygote from being a viable, fertile adult.
4.
Describe five prezygotic isolating mechanisms and give an example of each.

Habitat isolation- two species living in different habitats w/in the same area that rarely encounters each other but not geographically isolated from one another. Ex. two species of garter snakes occur in the same areas but one species lives mainly in water and the other is mainly terrestrial.

Temporal isolation- species that breed during different times of the day, season, or year. Ex. The eastern spotted skunk and the western spotted skunk overlap b/c the eastern mates in late winter and the western one mates in late summer.

Behavioral isolation- they do rituals that attract mates and other behaviors that are unique to a species are effective reproductive barriers even between closely related species. Ex. Blue-footed boobies males do a high step so the females can see their bright blue feet.

Mechanical isolation- Mating is attempted but morphological differences prevent its successful completion. Ex. The shells of two species of snails spiral in different direction causing their genitals are not aligned.

Gametic isolation- Sperm of one species may not be able to fertilize the egg of another species. Ex. The sea urchins release sperm & eggs into the surrounding water but are unable to fuse.
5.
Explain why many hybrids are sterile.

If the chromosomes of the two parents species differ in number or structure, meiosis in hybrids may fail to produce normal gametes.
6.
Explain how hybrid breakdown maintains separate species even if gene flow occurs.

Some of the first generation hybrids are viable and fertile but if they mate w/ one another or w/ the parent species their offspring will be feeble or sterile.
7.
Describe some limitations of the biological species concept.

It does not apply to organisms that reproduce asexually such a prokaryotes. & they can’t evaluate the reproductive isolation of fossils.

8.
Define and distinguish among each of the following: ecological species concept, pluralistic species concept, morphological species concept, and genealogical species concept.

Ecological species concept- the sum of how members of the species interact w/ nonliving and living parts of their environment.

Pluralistic species concept- the idea that there is no universal explanation for the cohesion of individuals that make up species.

Morphlogical species concept- characterizes species by body shape & other structural features.

Genealogical species concept- individuals of a species are more closely related to one another than to any individuals outside the group.
9.
Distinguish between allopatric and sympatric speciation.

Allopatric speciation - speciation that occurs when gene flow is blocked by a geographical barrier that physically isolates the population

Sympatric speciation- speciation occurs in population that live in the same geographic area.
10.
Explain the allopatric speciation model and describe the role of intraspecific variation and geographic isolation.

One population becomes separated, populations diverge as they adapt.
11.
Define a ring species and describe an example found in salamanders.

Ring species is a spreading around a geographic barrier & the further it gets more divergent. In the salamanders the father that they were they had a harder time reproducing.
12.
Describe examples of adaptive radiation in the Galapagos and Hawaiian archipelagoes.

Galapagos has a very diverse environment as well as Hawaii. Hawaii has very unique species of either plants or animals.
13.
Explain how reproductive barriers evolve. Describe an example of the evolution of a prezygotic barrier and the evolution of a postzygotic barrier.

The reproductive barrier evolved though natural selection. Ex. Prezygotic: Fruit flies are able to adapt to different food. Postzygotic: Monkey flowers, pollinators have cause a strong barrier both monkey flowers,.
14.
Define sympatric speciation and explain how polyploidy can cause reproductive isolation.

Sympatric speciation- speciation occurring in populations that live in the same geographic area. Polyploidy is the result of extra sets of chromosomes. Which is caused by a problem in separation.
15.
Distinguish between an autopolyploid and an allopolyploid species and describe examples of each.

Autopolyploid- is an individual that has more than two chromosome sets that are all derived from a single species. Ex. in the cell division something can go wrong making it go from a 2n

4n.

Allopolyploid- various mechanisms can change a sterile hybrid into a fertile polyploid. Ex. goatsbread was introduce into the U.S. & they keep reproducing.
They reproduce w/ there own members by making more w/ parent species.

16.
Describe an example of sympatric speciation in fish.

Caused by sexual selection. Since the female selects her male by his color. It keeps the gene pool of them separate.
17.
List some points of agreement and disagreement between the two schools of thought about the tempo of speciation (gradualism versus punctuated equilibrium).

They agreed that the fossil records showed large period of no change what so ever. & if there was changed they were undocumented. They disagreed b/c divergence was continuous and gradual. There was some rapid change then stasis.
18.
Explain why speciation is at the boundary between microevolution and macroevolution
.

Microevolution is the change in the allele frequency. The changes in the gene pool gives rise to new species. & many speciation events constitute macroevolution.
19.
Define exaptation and illustrate this concept with an example.
 It is a shift in function through evolution. Ex. a bird’s wings were first for just the heat but later were used to fly.
20.
Explain how the evolution of changes in temporal and spatial developmental dynamics can result in evolutionary novelties. Define evo-devo, allometric growth, heterochrony, and paedomorphosis.

Few genes control timing. Small alterations can make a big difference.

Evo-devo i nterface between developmental and evolutionary biology.

Allometric growth- phenomenon whereby parts of the same organism grow at different rates

Heterochronya developmental change in the timing of events leading to changes in size and shape.

Paedomorphosis- the resemblance of adult animals to the young of their ancestors.
21.
Explain why extracting a single evolutionary progression from a fossil record can be misleading.

We do not have every single fossil from an ancestral species. Might imply direct lineage.
22.
Define and illustrate the concept of species selection. Explain why evolutionary trends are not directional.

Speciation occurs more w/ widespread species. Species appear to have a trend going on w/ the fossils. It makes all species traits look important.

Vocabulary.
1.
Macroevolution – Evolutionary change below the species level; change in the allele frequencies in the population over generations.
2.
Speciation –An evolutionary process in which the species splits into two or more species.
3.
Biological Species Concept – Definition of a species as a population or group of populations whose members have the potential to interbreed in nature & produce viable, fertile offspring, but do not produce viable, fertile offspring w/ members of other such groups.
4.
Prezygotic Barrier –A reproductive barrier that impedes making between species or hinders fertilization if interspecific mating is attempting.
5.
Postzygotic Barrier –A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults.
6.
Ecological Species Concept
– A definition of species in terms of ecological niche, the sum of how members of the species interact w/ the nonliving & living parts of their environment.
7.
Pluralistic Species Concept The idea that there is no universal explanation for the cohesion of individuals that make up species.
8.
Morphological Species Concept – A definition of species in terms of measurable anatomical criteria.
9.
Genealogical Species Concept - Individuals of a species are more closely related to one another than to any individuals outside the group.
10.
Allopatric Speciation – The formation of new species in populations that are geographically isolated from one another.
11.
Sympatric Speciation – The formation of new species in populations that live in the same geographic area.
12.
Adaptive Radiation –Period of evolutionary change in which groups of organisms form many new species whose adaptions allow them to fill vacant ecological roles in their communities.
13.
Polploidy -A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division.
14.
Autopolploid - An individual that has more than two chromosomes sets that are all derived from a single species.
15.
Allopolyploid – A fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes.
16.
Punctuated Equilibrium – In the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change.
17.
Exaptations - It is a shift in function through evolution.
18.
Allometric Growth - phenomenon whereby parts of the same organism grow at different rates.
19.
Heterochrony – Evolutionary change in the timing or rate of an organism’s development.
20.
Paedomorphosis – The retention in an adult organism of the juvenile features of its evolutionary ancestors.

21.
Homeotic - The transformation of one body part into another. Arising from mutation.
22.
Species Selection A unit of selection is a biological entity within the hierarchy of biological organization.