Variation and natural selection

Question 1

Continuous Variations

Answer 1

a characteristic that changes gradually over a range of values shows continuous variation. Examples of such characteristics are: height.

Question 2

Discontinuous variation

Answer 2

A characteristic of any species with only a limited number of possible values shows discontinuous variation. Human blood group is an example of discontinuous variation.

Question 3

Genetic Variation

Answer 3

When organisms genotype is different, for example blood groups are controlled by genes

Question 4

Environmental variation

Question 5

Environmental variation

Answer 5

Environmental variations is the factors in the environment that effect the growth of a organism.

Question 6

Causes of genetic variation

Answer 6

Mutation – When a gene suddenly changes

Question 7

Mutagens

Answer 7

The chemicals which can cause mutations are called mutagen. (Ionising radiation and heavy metals such as lead or mercury)

Question 8

Adaptive features

Answer 8

The features which allow organisms survive in their environment, organisms which are most adapted to its surrounding increases the chance or survival.

Question 9

Fitness

Answer 9

The probability of an organism surviving and reproducing in the environment in which it is found in.

Question 10

Meiosis

Answer 10

When garmetes are formed during sexual reproduction. In meiosis the chromosomes exchange genes making the garmetes formed different.

Question 11

Fertilisation

Answer 11

Any two gametes can fuse together at fertilisation. many possible combinations may be produced at the zygote.

Question 12

Xerophytes

Answer 12

Plants such as cactus and succlents that live in desserts with high temperatures and low water supply, have adaptations to help them live in places with short supply of water. These plants are called Xerphytes

Question 13

Adaptations of Xerophytes

Answer 13

• Closing stomata
• Waxy cuticle
• Hairy leaves
• Stomata on underside of leaves
• Cutting down on the surface area
• Having deep or spreading roots

Question 14

Hydrophytes

Answer 14

Plants that have adaptations to live in wet areas, including in water are called hydrophytes

Question 15

Selection

Answer 15

• Variation
• Over production
• Struggle for existence
• Survival of the fittest
• Advantageous characteristics passed to offspring
• Gradual change

Question 16

Process of adaptation

Answer 16

the process resulting from natural selection, by which populations become more suited to their environment over many generations