B12c Developing understanding of genetics (triple only)

Question 1

Name the scientist who proposed the theory of evolution by natural selection

Answer 1

Charles Darwin

Question 2

Outline how Darwin arrived at his theory of evolution by natural selection

Answer 2

Observations on a round the world expedition
Years of experimentation and discussion
Linked to developing knowledge of geology and fossils

Question 3

Outline the process of evolution by natural selection

Answer 3

individual organism within a particular species show a wide range of variation
individuals with characteristics most suited to the environment are more likely to survive and breed successfully
Beneficial characteristics are passed on to the next generation

Question 4

Name the book Darwin published describing his ideas

and the date of publication

Answer 4

On the origins of species
1859

Question 5

Why was the theory of evolution by natural selection initially not accepted?

Answer 5

Theory challenged the idea that God made all the animals and plants that lived on Earth
Insufficient evidence at the time to convince many scientists
Mechanism of inheritance and variation was not known until 50 years after the theory was published

Question 6

Name another scientist working on other theories explaining the changes that occur in an organism

Answer 6

Jean-Baptiste Lamarck

Question 7

What was Jean-Baptiste Lamarck’s theory of evolution?

Answer 7

Changes occur in an organism during its life time can be inherited

In most cases this type of inheritance cannot occur

Question 8

Name the scientist who independently proposed the theory of evolution by natural selection and published joint writings with Darwin

Answer 8

Alfred Russel Wallace

Question 9

What did Wallace work on?

Answer 9

Gathering evidence for evolution
Warning colouration in animals
Theory of speciation

Question 10

Name the two scientists that proposed the theory of evolution

Answer 10

Darwin and Wallace

Question 11

What cuases Darwin to publish his Origin of Species?

Answer 11

Wallace proposed his theory of evolution

Question 12

What is speciation?

Answer 12

Formation of a new species
Two populations become so varied that they cannot interbreed to produce fertile offspring

Question 13

Give a definition of species

Answer 13

A group of organisms with similar characteristics which are able to breed to produce fertile offspring

Question 14

Outline the process of speciation through geographic isolation

Answer 14

Two populations of the same species are separated geographically
Geographic isolation prevents interbreeding and mixing of alleles between the populations
Different alleles are selected for in each geographical area
Different phenotypes develop in each population
Over time, the tow populations may evolve so that they are not able to interbreed.

Question 15

Why is genetic variation important in speciation?

Answer 15

Genetic variation produces phenotypic variation
Some phenotypes are better suited to the environment and are selected for

Question 16

How did Mendel study inheritance?

Answer 16

Breeding experiments on pea plants and analysing the ratio of characteristics in offspring

Question 17

Why was Mendel’s work not recognised until after his death?

Answer 17

Could not explain the mechanism of inheritance (chromosomes only discovered after his death)
Behaviour cf chromosomes in cell division had not been observed
Not communicated well to other scientists and not published in a reputable scientific journal

Question 18

When was cell division first observed?

Answer 18

Late 19th century

Question 19

When was the strucutre of DNA determined?

Answer 19

Early 20th century

Question 20

What word did Mendal use to describe what we now call genes

Answer 20

Units