Lecture 3: Speciation

Question 1

Define macroevolution?

Answer 1

broad patterns of evolutionary change above the species level (ex: origin of new species)

Question 2

Define what is speciation?

Answer 2

formation of a new and distinct species in the course of evolution. (*evolution of reproductive isolation)

Question 3

What forms a conceptual bridge between Marco and micro evolution?

Answer 3

speciation

Question 4

why does name species and identifying them are an issue?

Answer 4

-NO universal definition
-species concept

Question 5

What are the two species concept?

Answer 5

-morphological species concept
-biological species concept

Question 6

What is the principle of morphological species concept?

Answer 6

-distinguish by body shape
-structural features
-emphasize pattern or appearance
-convergent evolution

Question 7

Why morphological species concept is an issue?

Answer 7

-subjective criteria
-not reliable
-some different species can look alike

Question 8

What is the principle of biological species concept?

Answer 8

-group of members who have the potential to interbreed

Question 9

What is the main problem with the biological species concept?

Answer 9

-Don’t apply to all situations
need to think about fossiles? asexual organism? hybridization?

Question 10

What is the solution to identify species?

Answer 10

to use binomial nomenclature

Question 11

What are two processes occurring during speciation?

Answer 11

-identical populations must diverge (genetic composition)
-Reproductive isolation must evolve to maintain these differences

Question 12

What is a type of agent of evolution that erase any genetic differences?

Answer 12

gene flow

Question 13

what is the goal of achieving genetic isolation?

Answer 13

so new species can arise

Question 14

what are the two conditions for new species to arise?

Answer 14

-allopatric speciation
-sympatric speciation

Question 15

What is the principle of allopatric speciation?
(3 points)

Answer 15

-population living in different locations
-physical barrier blocks gene flow
-population evolves differently

Question 16

If the population where bring back together would they be able to interbreed?

Answer 16

no

Question 17

if the population is small what agent of evolution will allow divergence?

Answer 17

genetic drift

Question 18

What are examples of instances of allopatric speciation?

Answer 18

-geographical isolation
-continental drift

Question 19

What is the main effect of geographical isolation?

Answer 19

-colonization of remote areas by one or few individuals
-barries to movement – split ancestral population
-Extinction of intermediate populations

Question 20

What is the principle of sympatric speciation?

Answer 20

-speciation within the same area
-disruptive selection
-polyploidy creates new species

Question 21

What is polyploidy?

Answer 21

-organism with an extra set of chromosomes
-chromosome can replicate but can’t seperate

Question 22

In what kingdom polyploidy is common?

Answer 22

plants

Question 23

Does different policy can reproduce?

Answer 23

no

Question 24

What is reproductive isolation during speciation process?

Answer 24

gene flow must be restricted during that time

Question 25

What are the two mechanisms of reproductive isolation?

Answer 25

-prezygotic -postzygotic

Question 26

What is prezygotic mechanisms?

Answer 26

mechanism that prevents formation of zygotes

Question 27

What is postzygotic mechanisms?

Answer 27

mechanism that prevent the proper development of zygotes after they are formed

Question 28

What are 5 examples of reproduction Barries for pre zygotic mechanisms?

Answer 28

-geographical isolation -ecological isolation -behavioural isolation -mechanical isolation -prevention of gamete fusion

Question 29

What is geographical isolation?

Answer 29

separated by physical barriers -- gene pool will remain separate

Question 30

What is behavioural isolation?

Answer 30

-sympatric species avoid mating with wrong species

Question 31

In behavioural isolation what are the 3 hints that they have found the wrong species?

Answer 31

-visuals signals -sound production -pheromones

Question 32

What is ecological isolation?

Answer 32

occupying different habitat -- will never encounter

Question 33

What is temporal isolation?

Answer 33

reproduce in different seasons or different time of the day

Question 34

What is mechanical isolation?

Answer 34

can't reproduce due to structural differences

Question 35

What is prevention of gamete fusion?

Answer 35

gametes function poorly with the gametes of other species

Question 36

What are post zygotic mechanisms?

Answer 36

-hybrid inviability -hybrid breakdown -hybrid sterility

Question 37

How does post zygotic prevent zygote from developing? (3 points)

Answer 37

-structures -functions -development abnormalities

Question 38

What is hybrid inviability?

Answer 38

when fertilization can't occur when hybrid can't reach maturity to breed

Question 39

What is hybrid sterility?

Answer 39

if they develop they may be sterile

Question 40

What is hybrid breakdown?

Answer 40

when the first generation is vigorous and can reproduce but the offspring's are weak and often die

Question 41

What is adaptive radiation?

Answer 41

when species find themselves in a new/sudden changed environment -- evolution of new traits will allow individuals to use certain part of the environment that wasn't used before

Question 42

What is the role of natural selection and niche adaptation in reinforcing speciation?

Answer 42

they promote divergence between populations and they reduce gene flow -- ensuring that emerging species remain distinct and they don't merge back into a single population