Variation

Question 1

Describe the term variation

Answer 1

Differences between individuals of the same species

Question 2

Describe phenotypic variation. And what are the two types?

Answer 2

Differences in the visible characteristics of the same species.

Continuous and discontinuous phenotypic variation

Question 3

What is genetic variation?

Answer 3

Differences in genes

Question 4

What causes Phenotypic variation?

Answer 4

• It can be caused by genes
• Or it can be caused by the environment (Characteristics of all species are affected by environmental factors)

Question 5

What are the environmental factors

Answer 5

• Climate
• Religion/culture
• Diet
• Accidents
• Lifestyle

Question 6

What is continuous variation?

Answer 6

• Small degree of differences
• No limit on the category
• No distinct categories
• Tends to be quantitative
• Controlled by genes and environment
• Represented by a line graph

Question 7

What is discontinuous variation?

Answer 7

• Distinct differences in the characteristics
• Distinct categories (like the A, B or O blood group)
• No in-between categories
• Tends to be qualitative
• Controlled by a few genes
• Results in limited phenotypes
• Represented by bar graph.

Question 8

What is mutation?

Answer 8

The random genetic changes to the base sequence of a DNA
They happen spontaneously and continuously

Question 9

How is the rate of mutation increased?

Answer 9

• Ionising radiation damages bonds and causes changes in the bade sequences (gamma rays, x-rays and ultraviolet rays)
• Certain chemicals (Tar/tobacco)

Question 10

What is sickly cell anaemia?

Answer 10

• Mutation in the gene produces an abnormal protein (Hb)
• The abnormal shape of the haemoglobin gives the blood cell a rigid, sickle-like shape that prevents oxygen-binding properties
• The cells get stuck in small blood vessels, which can slow or block blood flow.

Question 11

What are the 4 sources of genetic variation?

Answer 11

• Gene mutation
• Meiosis
• Random mating
• Random fertilisatioin

Question 12

What is gene mutation?

Answer 12

• the change in the base sequence of the gene during cell division
• The original sequence might have deleted/substitutes/inserted with a new copy
  The combinations produce a different allele that codes for different protein

Question 13

What are adaptive features?

Answer 13

Inherited functional features of an organism that increases its fitness (Probability of an organism surviving and reproducing in new environment)

Question 14

What are the three adaptive features of Hydrophytes

Answer 14

• Large air spaces in their leaves
• Stomata open and found on upper epidermis
• Small roots

Question 15

Name 4 adaptive features of Xerophytes

Answer 15

• Small leaves (reduce evaporation)
• Thick waxy cuticle
• Sunken stomata
• Leaf rolled with stomata inside
• Thick leaves
• Extensive shallow root