3.2 Natural Selection

Question 1

define natural selection

Answer 1

the process by which the organisms that are best adapted in a particular environment are most likely to survive and reproduce passing on their advantageous alleles to their offspring.

Question 2

define genotype

Answer 2

the genetic makeup of an organism with respect to a particular feature

Question 3

define phenotype

Answer 3

the physical traits (including biochemical characteristics) expressed as a result of the interaction between the genotype and environment

Question 4

a niche is. . .

Answer 4

a niche is the role of an organism within the habitat in which it lives.

Question 5

identify and describe 3 types of adaptations

Answer 5

ANATOMICAL- an adaptation involving the form and structure of an organism

PHYSIOLOGICAL- an adaptation involving the way the body of the organism works, including differences in biochemical pathways or enzymes

BEHAVIOURAL- an adaptation involving programmed or instinctive behaviour making organisms better adapted for survival.

Question 6

define selection pressure

Answer 6

the pressure exerted by a changed environment or niche on individuals in a population, causing changes in the population as a result of natural selection

Question 7

_____ _______ is the evolution of dark coloured individuals in a habitat that has been made darker by industrial pollution

Answer 7

INDUSTRIAL MELANISM is the evolution of dark coloured individuals in a habitat that has been made darker by industrial pollution

Question 8

what is directional selection?

Answer 8

directional selection is natural selection showing a change from one dominant phenotype to another in response to a change in the environment - one phenotype is selected for over all the others.

Question 9

a _____ _______ is all the variants of all the genes in a population.

Answer 9

a GENE POOL is all the variants of all the genes in a population.

Question 10

Outline the theory of evolution

Answer 10

living organisms that reproduce sexually show great variety in their appearance

organisms produce an excess of offspring - many organisms produced do not survive to reproduce themselves . therefore there is constant competitions between members of the same species

organisms that inherit characteristics that give them an advantage to survive and pass on the desired feature to their offspring.

organisms inherit characteristics that put them at a disadvantage will be more likely to die out before they can reproduce.

Question 11

difference between natural selection and evolution

Answer 11

natural selection is the process by which evolution occurs but natural selection does not necessarily lead to the evolution of a new species

Question 12

Identify the types of adaptations that organisms require to successfully adapt for their niche

Answer 12

Anatomical Adaptations- form and structure of organism.

Behavioural adaptations- changes in programmed or instinctive behaviour making organisms better adapted for survival.

Physiological adaptations- the way the body of the organism works, includes differences in biochemical pathways or enzymes

Question 13

Outline the evolution of antibiotic resistance by natural selection.

Answer 13

Original population includes some mutations

Antibiotic is taken

Bacteria with resistant mutation more likely to survive

New population has higher proportion containing the advantageous resistant bacteria.

Antibiotic taken

Only bacteria with resistant mutation survive

New population almost entirely resistant to antibiotic apart from new mutants.

Question 14

Reasons behind the antibiotic resistance bacteria problem

Answer 14

Antibiotics too widely prescribed/used

Not completing courses of antibiotics

Antibiotics used in food chains

Lack of hygiene in hospital spreads MRSA

Question 15

Ways of overcoming antibiotic resistance problem

Answer 15

Reduce the use of antibiotics

Better education to make people understand they do not need antibiotics

Reduce use of antibiotics in farm animals

Development of new antibiotics

Question 16

Define speciation

Answer 16

the formation of new species

Question 17

Define hybridisation

Answer 17

the production of offspring as a result of sexual reproduction between individuals from 2 different species

Question 18

Define Allopatric speciation and the other one

Answer 18

Allopatric- speciation that takes place when populations are physically or geographically separated so that there can be no interbreeding and or geneflow between populations

Sympatric- speciation that takes place between populations of species living in the same place. they become reproductively isolated by mechanical, behavioural or seasonal mechanisms and gene flow continues between the populations to some extent as speciation takes place

Question 19

An ________ species is a species that evolves in geographical isolation and is found in only one place.

Answer 19

An ENDEMIC species is a species that evolves in geographical isolation and is found in only one place.

Question 20

_________ ___________ occurs when two populations inhibit the same region but develop preferences for different parts of the habitat.

Answer 20

ECOLOGICAL ISOLATION occurs when two populations inhibit the same region but develop preferences for different parts of the habitat.

Question 21

define Adaptive radiation

Answer 21

Adaptive radiation is the process by which one species evolves rapidly to form a number of different species that all fill different ecological niches

Question 22

identify and describe the 3 types of Sympatric isolations

Answer 22

Types of SYMPATRIC Isolations:

BEHAVIOURAL- when changes occur in courtship ritual, display or mating patterns so some animals do not recognise others as being mating mates.

MECHANICAL- when a mutation occurs that changes the genitalia of animals making it physically impossible for them to reproduce weight other members of the group.

SEASONAL- when time of flowering/sexual receptiveness in some parts of the population drifts way from the norm of the group. this can lead to groups reproducing at different times