Topic 4 - Natural Selection And Genetic Modification Flashcards
What’s evolution?
Evolution is the slow and continuous change of organisms from one generation to the next.
What did Charles Darwin come up with?
Charles Darwin came up with the theory of natural selection to explain how evolution occurs
Why do individuals in a population show genetic variation?
How do new alleles arise?
Because of a difference in their alleles. New alleles arise through mutations
What things can effect an organisms chance of reproducing ?
- predation
-competition for resources
-disease
What’s the advantage of animals have characteristics better adapted to selection pressures?
What does this lead to?
-The animals with the characteristics that make them better adapted to their environment have a BETTER CHANCE OF SURVIVAL ARE MORE LIKELY TO BREED SUCESSFULLY and pass on their genes
-this means that the alleles responsible for the useful characteristics are more likely to be passed on to the next generation.
What will happen if individuals are less well adapted to their environment ?
They will be less able to compete , so are less likely to survive and reproduce
What do fossils provide evidence for?
Fossils provide evidence for evolution
What is a fossil?
A fossil is a trace of a plant or animal that lived a long time ago. They’re most commonly found in rocks
What’s is likely to mean if a rock is deep?
The deeper the rock, the older the fossil.
Why are rocks useful to scientists for providing evidence of human evolution?
Fossils in chronological order show gradual changes. This shows how a species has changes and developed.
How can bacteria prove evidence for evolution?
1) bacteria develop random mutation. make them
resistant to an antibiotic
2) if they resist they can survive longer and as a result reproduce more
3) allele from antibiotic resistance being passed onto more offspring
4) makes bacteria better adapted to the environment they live in and around antibiotics
What theory did Charles Darwin come up with?
Charles Darwin came up with the theory of evolution by natural selection.
What did Charles Darwin notice?
Charles Darwin noticed there was variation between members of the same species. Those with characteristics best suited to their environment were most likely to survive.
Stages of natural selection?
1) variation- species will have differences
2) natural selection- animals not well adapted die off
3) inheritance - good characteristics passed on
4) evolution- all animals not suited die of so the ones left over are well adapted
What were one of Wallace’s observations that provided the theory of evolution by natural selection?
Wallace realised that some species use warning colours to deter predators.
How has evolution influenced modern biology.. classification , antibiotic resistance, conservation
Classification- we are all related in some way, classify organisms on how closely related they are.
Antibiotic resistance - constantly develop new antibiotics to fight newly evolved bacteria
Conservation- importance of genetic diversity helping populations adapt to changing environments. Led to conservation projects
What are human beings and their ancestors known as?
hominids
What happened to brain size as our ancestors evolved?
As they got more intelligent their brain and skull size increased
How old was the ardi fossil?
How old was the Lucy fossil?
Ardi fossil - 4.4 million years old
Lucy fossil - 3.2 million years old
What did Richard Leakey and his team do?
They went to Kenya and found homo fossils. Found a turkana boy- 1.6 million year old fossil skeleton
Order from oldest to most recent of homo species ardipithecus and Australopithecus species?
Ardipithecus
Australopithecus
Homo species
How does complexity of stone tools prove evidence for evolution?
Because they started using stone tools that were more complex, this showed their brains must have been getting larger and they were getting more intelligent.
What 3 ways can scientists can date fossils?
1) looking at structural features. Simple tools are older
2) using stratigraphy, older rock layers are found under younger ones, so fossils in deeper layers are usually older
3)carbon-14 dating
What is a pentadactyl limb?
Examples of species that have them?
A limb with five digits
Eg: mammals , reptiles , amphibians
How does the pentadactyl limb provide evidence for evolution?
Similarity in bone structure provides evidence that species with pentadactyl limbs came from a common ancestor. Bats and humans both have pentadactyl limbs