Speciation

Question 1

Define speciation

Answer 1

Speculation is the evolutionary processes that lead to the formation of two or more new species from one species.

Question 2

What are the two types of speciation?

Answer 2

1. Allopatric speciation
2. Sympatric speciation

Question 3

Define allopatric speciation

Answer 3

Allopatric speciation occurs when two or more populations are prevented from breeding by geographical separation.

Question 4

What is sympatric speciation?

Answer 4

Refers to the evolution of two or more new species from single population within the same place.

Question 5

what is gene flow

Answer 5

Gene flow is the movement of genes from one population to another, through interbreeding/ It introduces new genes into a population and makes populations more genetically similar.

Question 6

list 5 geographical physical barriers

Answer 6

1. Rivers
2. Mountain ranges
3. Oceans
4. Lakes
5. Canyons

Question 7

define what a species is

Answer 7

A species is commonly defined as a group of organisms that are able to breed together to produce fertile offspring.

Question 8

what are the 4 steps of speciation

Answer 8

1. Variation
2. Isolation
3. Selection
4. Reproductive isolation

Question 9

describe variation (step one)

Answer 9

All populations show different degrees of variation between individuals both phenotypically and genotypically.

Question 10

describe isolation (step two)

Answer 10

Isolation involves a population split into two by a geographic barrier that stops the gene flow between both populations.

Question 11

describe selection (step three)

Answer 11

Different selection pressures involve natural selection to favour different characteristics in each sub population. Therefore gene pools change independently of each other
Because there is no gene flow between the two populations mutations that arise in one population will not appear in the other.

Question 12

describe isolation (step four)

Answer 12

Eventually, the two populations accumulate enough genetic differences that they can no longer interbreed, or produce fertile offspring.

Question 13

what are 6 key differences of speciation from evolution

Answer 13

1. Geographical barriers separate populations
2. Gene flow ceases
3. Different selection pressures in each population
4. Different mutations occur in each population
5. Each population evolves in isolation from the other
6. Eventually, the gene pools have accumulated so many differences that they are no longer the same species

Question 14

How does gene flow change allele frequencies in the gene pool of a population?

Answer 14

• Gene flow is the movement of genes from one population to another, through interbreeding/ It introduces new genes into a population and makes populations more genetically similar.
• Happens when individuals migrate from one population to another and then contribute to the gene pool.
• Migrants may have different alleles.
• Immigrants can introduce new alleles and emigrants can remove alleles.