darwin's theory of natural selection

Question 1

his 5 key observations

Answer 1

• individuals of a species vary in many traits
• variation can be passed on to offspring
• every population produces more offspring than can survive so some traits die off and do not survive
• generally population numbers for species are stable
• food and many other resources are limited

Question 2

darwin’s conclusions (inférences based on observations)

Answer 2

• individuals within a population compete for resources in order to survive
• some individuals will inherit characteristics that give them a better chance of surviving and reproducing a.k.a. survival of the fittest
• as the more favoured individuals reproduce the favourable variations become more common

Question 3

darwin’s theory of natural selection

Answer 3

• The change in population over time as advantages heritable traits become more common generation after generation
• this results in a population that is better adapted to its current environment
• this is the way in which nature favours the reproductive success of some individuals within a population over others
• The first step is variation when there is genetic variation within a population which can be inherited
• The second step is competition which is over production of offspring which leads to competition for survival
• The third step is adaptations which is when individuals with beneficial adaptations are more likely to survive to pass on their genes
• the final step is selection which is when over m au generations there is a change in allele frequency (evolution)