Evolution Flashcards
What is a vestigial structure?
Structures in an organism that have lost most or all of their function
How are fossils used to justify evolution?
In the early 1900s, geologists noticed that the stratification of cliff faces which were exposed on coastlines often had fossils in each layer.
They used the different layers to set geological time to and to give a rough age of the fossils that were present.
How is selective breeding used to justify evolution?
It proves that selection can cause evolution and in a relatively short period of time.
What is the main example for comparative anatomy?
The pentadactyl limb or 5 membered limb
What are the 6 ways to justify evolution?
- Fossils
- Selective Breeding
- Comparative Anatomy
- Comparative Embryology
- Vestigial Structure
- Speciation and gradual divergence/a.k.a. ‘biogeography’
What is the basic definition of natural selection?
An increase in frequency of traits (genes) which increase the suitability (fitness) to the environment
What is a gene pool?
The total set of genes in a population
What is natural selection (detailed)?
Natural selection is a change in allele frequency in the gene pool of a population favouring alleles that provide individuals with a survival advantage. The individuals with favourable traits are better able to survive and reproduce, passing traits on to offspring. It occurs over many generations.
What are the five key aspects of natural selection?
- Inherited Variation
- Adaptation
- Competition
- Selection
- Evolution
What can cause variation in inherited traits?
- Mutation (genetic information is randomly changed and then that mutated gene is passed on to offspring. This offspring will have different traits to other members of the population)
- Meiosis (cell division to produce gametes means that genetic information is randomly assembled so that it is different from the parent. We call this recombination.)
- Immigration (when new organisms join a population, they bring with them new genetic information which may be introduced to the population.)
Can an organism ever be perfectly adapted to it’s environment?
No, an environment is always changing.
What example demonstrates evolution occurring within a population?
The Peppered Moth - there were black and white moths in the gene pool. The white moths were able to blend in with the tress better, so they could live and pass on their DNA. During the industrial revolution, the soot and smoke covered the tress black, meaning that the black moths then thrived. Later, the smoke was reduced to the adverse effects on the environment and people, so the trees became white again and the white moths became advantageous.
What is a species?
A group of actually or potentially interbreeding populations, which are reproductively isolated from other such groups.
What is reproductive isolation?
Any offspring must be viable and fertile for them to be the same species.
What are the types of speciation?
Allopatric and Sympatric
