Genetics and Variation

Question 1

Chromosomes in the Human body

Answer 1

46 chromosomes- arranged in 23 pairs

In each pair, there are two copies of a gene

Question 2

What are Dominant Genes?

Answer 2

One gene will override the other gene
They are genes expressed in both homozygous and heterozygous condition
eg. brown hair genes> blonde hair genes

Question 3

Alleles can be…

Answer 3

Recessive or Dominant

Question 4

What is the use of Punnet Squares?

Answer 4

Punnet squares are the simplified way of expressing what possibility of variation of genes can be made.

Question 5

Where is a cell’s genetic material found?

Answer 5

Genetic material is found in the nucleus.

Question 6

What is the shape of DNA?

Answer 6

Double Helix

Question 7

What does each gene code for?

Answer 7

Each gene codes for an inherited characteristic.

Question 8

What are alleles?

Answer 8

Different forms of the same gene

Question 9

Continuous Variation is…

Answer 9

variation with no limit for the population eg. height

Line graphs are used to plot this kind of data

Question 10

Discrete Variation is…

Answer 10

variation with distinct groups eg. hair/eye colour

Question 11

Evolution is…

Answer 11

the process that organisms have developed from earlier forms of life

Question 12

Extinction is…

Answer 12

the complete disappearance of a species from Earth

Question 13

What is a fossil?

Answer 13

A fossil is the remains or impression from a prehistoric organism embedded in rock and preserved in petrified form

Question 14

Heterozygous is…

Answer 14

two different alleles eg. Aa

Question 15

Homozygous is…

Answer 15

two copies of the same allele eg. aa

Question 16

Inherited variation is…

Answer 16

variation caused by inherited genes from the offspring’s parents

Question 17

What is an invertebrate?

Answer 17

An animal without a backbone

Question 18

What is natural selection?

Answer 18

The process where organisms better adapted to their environment survive to breed and pass on their genes.

Question 19

Recessive is…

Answer 19

characteristics only expressed in the homozygous condition

Question 20

Phenotype is…

Answer 20

physical appearance due to your genotype

Question 21

How do fossils form?

Answer 21

• Impression
• Preservation
• Mineral replacement

Question 22

Preserved organisms form when…

Answer 22

amber is secreted and catches animals and plant matter in its resin. Amber is the prehistoric remains of the tree resin keyword- cretaceous ambers

Question 23

Only 1% of bones become…

Answer 23

fossils

Question 24

Factors for fossilisation: Body Type…

Answer 24

fossilisation prefers animals with hard parts like bones, shells and teeth

Question 25

Factors for fossilisation: Exposure…

Answer 25

fossilisation requires dead animals to be buried rapidly, near or in water… or in arid deserts where wind buries the animals

Question 26

What happens to fossils that aren’t buried quickly enough?

Answer 26

Animals left out in the open will be erased through the process of decalcification, erosion and corrosion

Question 27

Factors for fossilisation: Sediment…

Answer 27

Dry sand or alkaline mud is a good place for fossil formation

Question 28

Factors for fossilisation: Petrification…

Answer 28

Bones are completely dissolved but leave fossil stone photocopies

Question 29

Example of things that living organisms compete for are…

Answer 29

• food
• territory
• water
• mates
• space
• light
• mineral’s ion

Question 30

The smallest group in natural selection system is…

Answer 30

species

Question 31

Genetic Variation…

Answer 31

is caused by DNA mutation and occurs between species, passed from parents to offspring through reproduction

Question 32

Examples of what causes extinction are…

Answer 32

• rapid environmental changes
• new predators
• new disease
• competition
• catastrophic events