Speciation 3.24

Question 1

A single species

Answer 1

Consists of a large number of populations spread across a country / countries

Question 2

Speciation

Answer 2

Formation of a new species happens as a result of the isolation of parts of a population

Question 3

Two isolated populations

Answer 3

Experience different conditions - natural selection works in different directions on the new populations

Question 4

Overtime

Answer 4

Both genotype and phenotype of isolated group will change to the point where of the split populations were reunited they can no longer successfully interbreed

Question 5

Hybridization

Answer 5

Can cause speciation especially in plants two related species can breed and for, hybrids successful in their own right and better adapted to their niche
Or hybrids don’t for fertile offspring crossed back to their parents new species formed which may out compete the parent plants

Question 6

Geographical isolation

Answer 6

Physical barrier such as as river or mountain range separates individuals from an original population

Question 7

Ecological isolation

Answer 7

Two populations inhabit the same region but develop preferences for different parts of the habitat

Question 8

Seasonal / temporal isolation

Answer 8

The timing of flowering or sexual receptiveness in some parts of a population drifts apart from the norm of the group .the can lead to the, reproducing several months apart

Question 9

Behavioral isolation

Answer 9

Changes occur in the courtship ,ritual ,display or mating pattern so that some animals do not recognize each other as being potential mates. This might be due to a mutation that changes the colour or pattern or markings

Question 10

Mechanical isolation

Answer 10

A mutation occurs that changes the genitalia of animals making it physically impossible for them to mate successfully with some members of the group or changes in the relationship between the stigma and stamens of flowers making pollination between some individuals unsuccessful

Question 11

Allopatric speciation

Answer 11

When populations are physically or geographically separated in some way
Main evolutionary process
E.g islands form and disappear ice floes melt
Human interventions like dams roads and cities

Question 12

Endemic

Answer 12

When a species evolves in a geographical isolation and found in one place

Question 13

Allopatric speciation is frequently followed by

Answer 13

Adaptive radiation

Question 14

Adaptive radiation

Answer 14

When one species evolves rapidly to form a number of different species which all fill different ecological niches
Variation in alleles and characteristics and different niches would favor different individuals

Question 15

Sympatric speciation

Answer 15

Takes place between populations of a species living in the same place that become reproductively isolated by mechanical ,behavioral or seasonal changes .
Gene flow continues to some extent as speciation takes place

Question 16

Sympatric species

Answer 16

Closely related and occupy overlapping ranges

Question 17

Why reluctant to classify example of sympatric speciation

Answer 17

When speciation occurs always a adaptive pressure including the presence of unrecognized micro habitats which drive the formation of two species and produce a barrier between the populations