Genetics and Variation Key Terms

Question 1

Allele

Answer 1

Different forms of the same gene

Question 2

Chromosome

Answer 2

Thread like structures made of DNA

Question 3

Continuous variation

Answer 3

Variation with no limit for the population e.g. height.

We use a line graph to plot these data

Question 4

Discrete variation

Answer 4

Variation with distinct groups e.g. eye colour.

We use a bar chart to plot these data

Question 5

DNA

Answer 5

Material that genes are made of

Question 6

Environmental variation

Answer 6

Variation caused by the environment in which an offspring is brought up

Question 7

Evolution

Answer 7

Process by which organisms have developed from earlier life forms on earth

Question 8

Extinction

Answer 8

The complete disappearance of a species from earth

Question 9

Fossil

Answer 9

The remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form

Question 10

Gene

Answer 10

A section of DNA that codes for a particular characteristic

Question 11

Inherited variation

Answer 11

Variation caused by the genes offspring inherit from their parents

Question 12

Invertebrate

Answer 12

Animal without a backbone

Question 13

Vertebrate

Answer 13

Animal with a backbone

Question 14

Natural selection

Answer 14

Process where organisms better adapt to their environment and survive to breed and pass on their genes

Question 15

Genotype

Answer 15

The two alleles that an organism has (from parents)

Question 16

Phenotype

Answer 16

Physical appearance due to your genotype

Question 17

Heterozygous

Answer 17

Two different alleles (e.g. Aa)

Question 18

Homozygous

Answer 18

Two copies of the same allele (e.g. aa)

Question 19

Dominant

Answer 19

Characteristic expressed in both homozygous and heterozygous condition

Question 20

Recessive

Answer 20

Characteristic only expressed in homozygous condition

Question 21

Species

Answer 21

A group of organisms that have characteristics in common and can interbreed to produce fertile offspring

Question 22

Mutation

Answer 22

A random change in genes. Mutations bring about variation