Evolution Flashcards
What was the ship called on which Darwin went on a voyage?
HMS Beagle (1831- 1836)
What is evolution?
Evolution is the concept that life on Earth has changed.
What is the evidence for evolution?
1) The age of the Earth is old enought for evolution to have occured.
2) Fossil evidence:
- increasing complexity as you move from older rocks to younger rocks
- a progression from aquatic environment to land.
What are fossils. Give some examples.
Fossils are any evidence of a past living thing, e.g. bones, frozen bodies, cast of shells, moulds of leaves, worm burrows, etc.
What is needed for a fossil to form and why?
A quick burial so decay is minimsed.
What part of the animal is usually preserved in a fossil?
Hard part of animals
What are some ways fossils form?
1) Frozen in ice, i.e.woolly mammoths
2) Dried in a cave, e.g. dingos
3) Buried
What is a mould?
The hollow formed in a rock when the parts of an organism have dissolved/ decayed.
What is a cast?
Rock formed by minerals filling the mould formed in rock.
What is permineralisation?
Organic matter is replaced mineral by mineral to provide a cast made of the minerals and organic matter, e.g. fossilised wood.
What are transitional forms? Give an example of one.
Organisms that display characteristics that bridge two groups, e.g. Archaeopteryx- it has the feather of a bird but the bone structure of reptiles.
Describe progressive fossils.
Some organisms are well represented in the fossil record, and show a great progression over time.
Describe embryology in terms of fossil evidence.
In the early stages of evolution, many embryos looked similar. this is evidence of common ancestry.
What is the theory of natural selection?
Theory that evolutionary change comes through the production of variation in each generation of species.
What things are needed for natural selection to occur?
1) Variation (arises through mutation and sexual reproduction)
2) A change in the environemnt
The causes a ‘battle for survival’ amongst the existing varitey and any new mutations. If a mutation is better suited, it is more likely to survive.
3) ‘Survival of the fittest’
Those who fit the new environment the best are more likely to breed and pass on their characteristic more often.
Over many generations, the new variety may eventually become the standard.
