4.3 Classification and evolution Flashcards
What is evolution?
Evolution is the theory that the differences between modern living organisms are because of changes that happened under the influence of natural selection over a very long period of time.
Who are Darwin and Wallace?
In the mid-1800s, Charles Darwin and Alfred Russel Wallace independently came up with a theory of evolution by natural selection. Natural selection is a mechanism to explain evolution could have occurred. The two men collaborated and co-published a paper in 1858. Darwin published his book, ‘On the Origin of Species’ in 1859.
How do fossil records show evolution?
We can examine extinct species and compare ancient organisms with modern ones. The age of the fossils can be measured by dating the rocks that they are found in. the fossil record gives us the fossils in chronological order.
How does DNA show evolution?
The DNA sequences of species can be compared to see how closely related species are.
How does molecular evidence show evolution?
The amino acid sequence of common proteins, such as cytochrome c, can be compared to see how closely related species are. Cytochrome c is an essential protein involved in respiration and is common to almost all organisms.
What are adaptations?
Traits or characteristics that help organisms survive and reproduce in their environment.
What are anatomical adaptations?
Physical changes in an organism’s body structure that help it survive in its environment.
What are behavioural adaptations?
Changes in behaviour that help an organism survive and reproduce in its environment.
What are physiological adaptations?
Physical changes in an organism’s body that help it survive and function in its environment.
What are some adaptations of animals living in extreme cold?
Have thick fur (anatomical),
Will build up thick layers of blubber under the skin in winter (physiological),
Huddle together for warmth (behavioural)
What is natural selection?
Natural selection is the process by which certain traits become more or less common in a population over time based on their ability to survive and reproduce.
How does natural selection work?
All organisms compete to survive and overcome selective pressures.
All organisms show variation.
Selection - some adapt enough to have offspring.
Adaptation - the offspring will have the same advantageous characteristics as the parents, if due to genetic information.
What must all organisms do to survive according to natural selection?
All organisms must compare to survive and overcome selective pressures.
What are some examples of selective pressures?
Food, water, predation, and disease are examples of selective pressures.
Why do all organisms show variation?
Variation among organisms is a natural occurrence that contributes to the process of natural selection.
