Inheritance & Variation

Question 1

Explain how a population would change into two different species.

Answer 1

The two populations are separated.
Genetic variation in each population such as different alleles are caused by mutations.
There are different environmental conditions between the two separated populations.
The better adapted survives (natural selection)
The survivors (with the better suited alleles) reproduce and the genes are passed on through the generations, in both populations.
Eventually the two types cannot interbreed to produce a fertile offspring.

Question 2

There was a different theory at the same time as Charles Darwin’s theory.
They said changes in an organism during their life can be inherited,
Who proposed this theory?

Answer 2

Lamarck

Question 3

Give one reason as to why a species would become extinct.

Answer 3

Changes to the environment.
New diseases

Question 4

What is the definition of a species?

Answer 4

Organisms that reproduce together to produce a fertile offspring.

Question 5

Two animals are separated species yet very alike.
Why have they not become different over time?

Answer 5

Similar environments and climate therefore they have similar adaptations and phenotypes.

Question 6

What is a pathogen?

Answer 6

A virus which causes diseases/infections.

Question 7

What temperature is most suitable for bacteria to grow?

Answer 7

40 ‘C

Question 8

What is evolution?

Answer 8

Gradual changes that occur in living organisms over millions of years.

Question 9

What must an organism do to pass down its genes/ alleles?

Answer 9

Reproduce

Question 10

How are new species formed?
(What happens to their genes?)

Answer 10

A mutation occurs in an organism, which results in new characteristics.

Question 11

How does a mutation become more common in the next generation?

Answer 11

The mutation in an organism’s genes gives them a survival advantage (helps them hide from prey/ hunt) and this organism survives and reproduces. Therefore their offspring inherits the mutated allele. Then this allele/gene becomes more common in the next generation.

Question 12

What process causes evolution?

Answer 12

Natural selection

Question 13

What is an advantage of a lot of genetic variation in a species?

Answer 13

Lower risk of extinction.

Question 14

What process does bacteria go through to increase their resistance in next generations?
How does it work?

Answer 14

Natural selection.
Overtime, antibiotic resistant bacteria evolve, and they survive and reproduce, therefore passing down their antibiotic-resistant alleles/genes to their offspring.
This creates a generation with a greater population of antibiotic-resistant bacteria.

Question 15

Why does bacteria evolve faster?

Answer 15

They evolve rapidly because they reproduce at a fast rate.

Question 16

What causes new strains of pathogens to develop?

Answer 16

Mutation/ genetic mutation.

Question 17

What was a reason that Darwin’s theory was not accepted in the scientific community?

Answer 17

Went against people’s religion (Christianity)
Insufficient evidence (not enough to back it up)
Inheritance and genes were unknown at that time.

Question 18

Who first developed the theory of evolution?

Answer 18

Charles Darwin.

Question 19

Lamarck’s theory

Answer 19

Proposed the theory that changes in living things happen ( during their lifetime ) can be inherited by their offspring.

Question 20

What is speciation?

Answer 20

New species of animals and plants occur through a process called speciation.

Question 21

What is meant by natural selection?

Answer 21

Survival of the fittest (only the fittest organisms have the adaptations to survive), and the reproduce and pass down their genes to the next generation.

Question 22

What does extinct mean?

Answer 22

No longer existing.

Question 23

Is Polydactyly caused by recessive or a dominant allele?

Answer 23

Dominant

Question 24

What is a heterozygous allele?

Answer 24

Dominant allele and a Recessive allele

Question 25

Is cystic fibrosis caused by recessive or a dominant allele?

Answer 25

Recessive
(So you’d need two)

Question 26

What is a carrier, sufferer, and fine?

Answer 26

Carrier -carry one copy of allele
-could pass it on
-don’t suffer from it

Sufferer -have the allele/s
-have the condition

Fine -doesn’t have the allele nor the condition

Question 27

If we had a phenotype of normal, but they both carried a heterozygous genotype for cystic fibrosis, what percent would the child have it?

Answer 27

25%

Question 28

What is embryo screening?

Answer 28

When an egg is fertilised with a sperm in the lab and then grows into an embryo, then take a cell and scan the genes for genetic disorders.

Question 29

Pros of embryo screening.

Answer 29

Save money in the future
Reduce overall suffering (fewer people with health problems).