Genetics And Evolution

Question 1

Controversy around Dawkins theory of natural selection

Answer 1

It challenged the creation story

Scientists regarded his evidence as inconclusive

Genes hadn’t been discovered so Darwin wad unable to suggest how the characteristics pass between parent and child

Question 2

Theory of inheritance

Answer 2

By lamarck

Changes in characteristics can happen in an animals lifetime then be passed on to offspring

Question 3

Individuals are members of the same species if

Answer 3

They can interbreed to produce fertile offspring

Question 4

What did Alfred Wallace propose

Answer 4

That new species developed as follows:

Two populations of the same species become separated

The populations show genetic variation

Due to different environments natural selection operates differently on the populations

This eventually leads to genetic divergence until the populations are unable to interbreed to produce fertile offspring, making them two different species

Question 5

Darwin and Wallace

Answer 5

Both spent a lot of time on islands

The two combined their knowledge to produce joint writings

Darwin then accelerated the publication of his book so he would be first to publish

Question 6

Evidence for evolution

Answer 6

Fossils - show gradual changes in organisms over vast periods

Antibiotic resistant bacteria - easily explained by natural selection

Question 7

3 ways to make fossils

Answer 7

Hardening soft materials with casts in them

Preservation where decay isn’t possible eg glaciers and peat bogs

Hard parts of organisms gradually replaced by minerals creating a rock like substance

Question 8

Understanding of genetics

Answer 8

Mid 19th century: model performed breeding experiments on pea plants which showed that characteristics were determined by inherited units passed from parents

Late 19th century
First observation of how Chromosomes behave during cell division

Early 20th century
Similarity between behaviour of Chromosomes and Mendlesham units recognised therefore it was decided that units were located on Chromosomes. The units were renamed genes

Mid 20th century
Scientists worked out structure of dna

Question 9

Extinction

Answer 9

Rapid extinction:
Sometimes physical factors change rapidly not allowing adaption or killing many in the species.

Slow extinction
Eg humans hunting