Evolution Flashcards
Define biodiversity.
Variation within living things.
Define evolution.
The change in the inherited characteristics of a population over time, eventually forming a new species.
Define speciation.
The formation of a new species.
How does speciation occur?
Variations of characteristics must be present in the population. The breeding population must be geographically isolated and different characteristics must arise through mutation, genetic drift or environmental factors. The environment must then change causing some characteristics to become favourable due to natural selection. These characteristics will be passed on to the next generation and the frequency of these genes increase. Eventually the isolated population becomes so different from the original that they are two separate species.
Define species.
A group of individuals that can interbreed to produce fertile offspring.
Define population.
A group of one species living in the same area, at the same time.
Define community.
The living species of a certain area.
Define ecosystem.
The living community, abiotic factors and interactions between them.
Define natural selection.
The tendency for organisms best suited to survive in an environment to live and reproduce.
What is necessary for natural selection to occur?
- variation
- selection pressures
- overproduction of offspring
How does natural selection work?
Selective pressures act on a population to create favourable characteristics. Individuals with these characteristics have an increased chance of survival and hence an increased chance of reproduction. These characteristics are passed down to the next generation and hence increase the number of individuals with these traits.
What is artificial selection?
Where humans choose which individuals breed to provide the desired characteristics.
Outline Lamark’s theory of evolution.
Suggested that organisms changed over their lifetime due to necessity. He believed that these acquired characteristics were then passed to the next generation.
Outline Darwin’s theory of evolution.
Believed that species evolved from a common ancestor over time through the process of natural selection.
Compare Lamark’s and Darwin’s theories of evolution.
Lamark believed in acquired characteristics while Darwin believed in inherited characteristics. They both believed that all organisms are related and that environmental change effects evolution.
