Speciation

Question 1

Allele frequency

Answer 1

The amount of alleles present in a populations gene pool

Question 2

Complete dominance

Answer 2

Where the form of heterozygous condition where the recessive allele is masked by the dominant one always

Question 3

Founder effect

Answer 3

This is referring to a small population of individuals that migrate to a new isolated area. The range and frequency of alleles is unlikely to be a representation of original population, some alleles won’t be present and some less frequent or more frequent

Question 4

Bottle neck effect

Answer 4

This is where the population maybe be suddenly reduced in numbers to a small size due to a catastrophic event or human action. Because numbers fall rapidly it’s likely that the range of alleles will decrease and frequency’s will change , if population was to ever increase in size they will have a decreased genetic diversity

Question 5

Gene pool

Answer 5

The total number of genes of every individual in a population

Question 6

Genetic drift

Answer 6

Is the change in the frequency of an existing gene variant in a population due to random chance alone and not natural selection

Question 7

Natural selection

Answer 7

Is a process in which the environment causes a particular allele to be beneficial over another. Individuals carrying this favourable gene were more likely to survive and reproduce. Increases the frequency of alleles

Question 8

Selective pressure

Answer 8

Can take many forms including environmental factors availability of food and energy sources and human influence. This means that animals don’t the these characteristics and are less likely to survive and reproduce

Question 9

Genetic drift

Answer 9

It is a change in the frequency of an existing gene variant in a population due to random change alone and not natural selection

Question 10

Convergent evolution

Answer 10

Two unrelated species evoke independently of each other however develop similar adaptations due to similar selection pressures

Question 11

Divergent

Answer 11

Common ancestors split into two species due to different ecological niches/ selection pressures resulting in natural selection

Question 12

Adaptive radiation

Answer 12

The evolution of an ancestral species which has adapted to a particular way of life each have adapted to specific habitats

Question 13

Parallel evolution

Answer 13

When common ancestors diverge but due to changing selection pressures they later develop similar features like wings or feet

Question 14

Co evolution

Answer 14

When different groups of organisms have close ecological relationships they have a strong effect on each others evolution

Question 15

The rate of evolution

Answer 15

Gradualism - slowly but continuously and eventually the accumulation of changes results or speciation occurring

Punctuated equilibrium - long periods of very little evolutionary change interrupted by short burst of rapid speciation, caused by sudden change in environment

Question 16

Modes of and RIMs

Answer 16

Prevents successful reproduction between two species and prevents gene flow between gene pools.

Question 17

Pre zygotic (before fertilisation)

Answer 17

Geographical, oceans rivers and mountains
Temporal, timing of reproduction
Ethnological, behavioural differences mating and courting behaviour
Ecological, different ecological niches no direct contact
Structural, anatomic differences sex organs not shaped the same
Gamete incompatibility- biochemical differences which prevent zygote from forming

Question 18

Post zygotic (after fertilisation)

Answer 18

Hybrid inviability the egg doesn’t develop as chromosomal incompatibility thus development problems and a low chance the offspring will survive.
Hybrid sterility, organism reaches maturity but is sterile
Hybrid breakdown, hybrid f1 is fertile but there offspring is sterile

Question 19

Allopathic speciation

Answer 19

Different origins selection would favour though would mate with own kind. This occurs in different geographical areas
Gene flow would be prevented
Isolated populations are subject to different selective pressures
Accumulated differences in two gene pools result in reproductive isolation

Question 20

Sympathetic speciation

Answer 20

Same origin occurs in the same geographical area and isn’t common in animals
Gene flow is prevented by mechanisms not geographical e.g behaviour or reproductive

Question 21

Mutation

Answer 21

A random permanent change in the base sequence of dna that changes amino acid order

Question 22

Allopolyploidy

Answer 22

A type of polyploidy in which the chromosome consists of more that two copies. It occurs when two species maye to produce a hybrid species

Question 23

Analogous structures

Answer 23

Superficially similar but have evolved in different ways

Question 24

Autopolyploidy

Answer 24

Multiple sets of chromosomes are all derived from the same species

Question 25

Cline

Answer 25

A gradual variation in characteristics of a species or population over a geographical range

Question 26

Deme

Answer 26

A population of organisms within which the exchange of genes is completely random

Question 27

Homologous structure

Answer 27

Structures that have similar evolutionary history but have developed to suit different functions

Question 28

Macro speciation

Answer 28

The formation of completely new species

Question 29

Micro evolution

Answer 29

The accumulation of through mutation new characteristics

Question 30

Nondisjunction

Answer 30

Is the failure of homologous chromosomes or sister chromatids to seperate properly during cell division resulting in cells with more that two copies of each chromosome

Question 31

Polyploidy

Answer 31

The cell or organism has three or more times the haploid chromosome number

Question 32

Selection pressures

Answer 32

The extent to which organisms possessing a particular characteristic are either eliminated or favoured by environmental demands

Question 33

Sub species

Answer 33

A group of individuals within a species that breed more freely among themselves than with other members of the species