Natural Selection Flashcards
1
Q
What is Evolution?
A
- The change of allele frequency within a population over time as a result of these processes.
2
Q
What was Darwin’s observation?
A
- All organisms produce more offspring than could ever actually survive (i.e. not all offspring survive)
- Populations of organisms do fluctuate (change over time) but not significantly (i.e. their numbers usually stay fairly constant)
- Populations of the same species of organisms show variation in characteristics between individuals (known as intraspecific variation)
- Offspring inherit characteristics from their parents
3
Q
What are the two evidences from these theories?
A
- Fossil evidence
- Molecular evidence
4
Q
FOSSILS
A
- Fossils are preserved remains of organisms or other features left by organisms, such as footprints, burrows and faeces
- changed significantly over millions of years
- They can be dated
- allowing us to put in sequence from youngest to oldest
- show similarities between extinct species
5
Q
MOLECULAR EVIDENCE
A
- DNA found in the nucleus of cells can be sequenced and used to provide evidence of evolutionary relationships between species and how the genetic code of species has changed as they have evolved
- The differences between the nucleotide sequences in the analogous genes of different species can provide a lot of information:
- The more similar the sequence the more closely related the species are
- Two groups of organisms with very similar DNA will have separated into separate species more recently than two groups with less similarity in their DNA sequences
