Science Definitions Flashcards
(18 cards)
Fittest
In evolution, fitness is about success at surviving and reproducing, not about exercise and strength
Central ideas of Darwin’s Theory of Evolution
- More offspring are born than survive to reproduce
- Variety exists in all species
- Those varieties that are “better adapted” to the environment are more likely to survive and reproduce - ‘survival of the fittest’. Less ‘fit’ individuals are weeded out by Natural Selection
- If the characteristics of different varieties are inherited by their offspring,
then the nature of a species will slowly change
Variation
Individuals with variations in characteristics best suited/adapted to their environment are more likely to survive and reproduce – passing on this variation via their genes to their offspring
Selective pressure
An environmental selection pressure impacts the survivability of organisms within a population and their ability to reproduce.
selective advantage
Individuals with advantageous traits are more likely to survive and reproduce under environmental pressures.
Heritability
The advantageous trait must be heritable, allowing it to be passed on from the parent to the offspring.
there for, overtime, the frequency of the advantageous allele will increase.
radiometric dating
Rocks are ‘dated’ by radiometric dating
i.e. half-life decay of radioactive elements
Vestigial structures
Features of an organism (no longer used) that is a historical remnant of a structure that served a function in the organism’s ancestors.
Variation
Individuals with variations in characteristics best suited/adapted to their environment are more likely to survive and reproduce – passing on this variation via their genes to their offspring
Discontinuous vairation
Has to be either one thing or the other.
E.g. Hair colour, Eye colour.
continuous vairation
Can have any value (can be measured with a ruler)
E.g. Height, Weight, Finger Length.
Embryonic evidence for evolution
Looking at the early stages of development of embryos suggests that we may have developed from a common ancestor.
Fossil record evidence for evolution
Strong evidence that supports the theory of evolution comes from examining the fossil record, and seeing how much, or how little, organisms have changed over time.
Genotype
Set of alleles an individual has.
Phenotype-
An individuals set of observable characteristics
homologous structures
Same basic structure; same relationship to other features; same development
eg. The forelimbs of a human, bat, whale, and cat are homologous structures
analogous structures
different structure adapted to the same environment
eg. Wings of a bird and a butterfly:
What is a mutation
a change to the DNA sequence
