Adaptation, Natural Selection And The Evolution Of Species and human impact on the environment

Question 1

Define mutation

Answer 1

Mutations is a random and spontaneous change to genetic material and the only source of new alleles.

Question 2

Mutations can be…

Answer 2

Advantageous- bacterial resistance to antibiotics (advantageous to bacteria)

Neutral - ear lobes free or attached

Disadvantageous- malignant melanoma (skin cancer)

Question 3

Define mutagenic agents

Answer 3

A mutagenic agent is a factor that can increase the rate of mutations

Question 4

Name mutagenic agents

Answer 4

Radiation
High temperatures
Some chemicals

Question 5

If mutations are neutral

Answer 5

They have little effect on the organism with the mutation

Question 6

Is mutations are harmful

Answer 6

They give the organism a disadvantage and so decrease its chances of survival

Question 7

If mutations are beneficial

Answer 7

They give the organism and advantage and so increase its chances of survival.

Question 8

Why are mutations important?

Answer 8

Mutations are the only source of new alleles

Mutations increase variation in a species

They allow a species to revolve in response to changing environmental conditions

Question 9

Define adaptation

Answer 9

An adaptation is an inherited characteristic that makes one organism well suited to its environment. This increases their chances of survival and being able to reproduce.

Question 10

Give an example of a structural adaptation

Answer 10

Rabbits ability to move quickly

Eagles large talons to grip onto prey

Pelicans webbed feet for swimming

Question 11

Give examples of behavioural adaptations

Answer 11

Bats are nocturnal to avoid predators and catch prey

Lions turn paws over when attacking because fur is quieter

Question 12

Genetic variation

Answer 12

Genetic variation within a population makes it possible for a population to evolve over time

Question 13

Describe natural selection.

Answer 13

Living organisms often produce more offspring than the environment can support due to the limited resource available.

Natural selection is the process in which election pressures allow only the best adapted to their environment to survive and go on to reproduce and pass on the favourable alleles to the offspring. Whilst those less adapted did before producing.

Question 14

Explain ‘survival of the fittest’

Answer 14

Darwin proposed that organisms better adapted to their environment survive.

Question 15

Define genotype

Answer 15

The type of genes an organism has. E.g. A gene for blue eyes

Question 16

Define phenotype

Answer 16

The physical appearance of an organism.

Question 17

Define selective pressure

Answer 17

An aspect of the environment that selects one characteristic over another for example climate, predators or disease.

Question 18

Define selective advantage.

Answer 18

The characteristic of an organism that enables it to survive and reproduce better than other organisms in a population in a given environment.

Question 19

Define species

Answer 19

A species is a group of interbreeding organisms whose offspring are fertile.

Question 20

Define speciation

Answer 20

Speciation is the process by which a new species is formed.

Question 21

Describe the process of speciation.

Answer 21

A large group of interbreeding organisms of the same species with a common gene pool are split up by an isolation barrier that prevents gene flow.
(Geographical, ecological, reproductive)
Random and spontaneous mutations occur within each population.
Natural selection favours the best adapted. After time the barrier is removed.
There is two different species if they interbreed to produce sterile offspring.

Question 22

The human population is increasing.

Answer 22

The increasing population requires an increases food yield.

Farmers achieve this through the use of intensive agriculture.

Question 23

Name the intensive farming methods used to increase food production.

Answer 23

Fertilisers

Pesticides

Biological control

GM crops

Question 24

Describe fertilisers.

Answer 24

Fertilisers are used to increase food production, get maximum crop yield and ensure food security.

Contains nitrogen, phosphorus and potassium.

N- important for plant leaves
P- important for plant roots
K- important for fruit and flowers

Question 25

Natural fertilisers vs artificial

Answer 25

Natural
Low pollution and low cost
But variable NPK content

Artificial
Reliable NPK content
But high pollution and high cost.

Question 26

Describe algal bloom

Answer 26

Fertilisers can leach into a fresh water source.
The nitrogen in fertilisers increase algae growth causing an algal bloom.
The Alfa bloom grows so large it blocks out sunlight and reduce light intensity which kills aquatic plants below.
The dead plants and some dead algae are eaten by decomposing bacteria.
The bacteria population increases and use up large quantities of oxygen.
Oxygen availability is reduced which means other organisms die and this reduces biodiversity in the fresh water source.

Question 27

Describe pesticides

Answer 27

Pesticides are chemicals used to kill organisms that are in competition with or eating crop plants.

Herbicides - used to kill plants
Insecticides - used to kill insects

Question 28

Define bioaccumulation

Answer 28

Pesticides for example DDT bioaccumulate in the bodies of organisms.
It is passed from one organism to the next through the food chain.
As the chemical is passed on up the food chain it increases in toxicity and can reach lethal levels.

The build up of harmful chemicals in the bodies of organisms.

Question 29

Describe biological control

Answer 29

An alternative to pesticide use

Biological control is the control of a pest species by the introduction of a natural enemy or predator.

Example, using ladybirds to control greenfly infestations.

Question 30

Describe GM crops

Answer 30

An alternative to fertilisers

Genetically modified crops are produced when a useful gene from another organism is inserted into the cells of a plant.

Question 31

Define indicator species

Answer 31

Indicator species that indicate levels of pollution by their presence or absence.

Question 32

What indicates water pollution?

Answer 32

Freshwater invertebrates

Question 33

What indicates air pollution?

Answer 33

Lichen