Population Dynamics Chap. 4 Flashcards
What is an adaptation?
It is a structural, behaviour or physicological process that helps an organism survive.
What is an inherited trait?
A set of traits that improve the chances of survival and reproduction of an organism.
What is a structural adaptation?
Structures that improve a species’ ability to survive and reproduce. Ex: Camouflauge
What is a behavioural adaptation?
Things that an organism does. ex: migration
What is a physiological adaptation?
Based on chemicals and internal processes. Ex: Pheromones, venom production
How do adaptation deveolp?
- Variation
- Mutations
What are varations?
Differences (visible or otherwise) among members of a population. Created by inheriting different combinations of genetic information from parents.
What are mutations?
Random, spontaneous changes in genetic material that can be passed from parents to offspring.
Are mutatiuons good?
They can be good, bad, or provide no advantage or disadvantage.
What are the requirents for a mutation to be passed on to offspring?
Mutation must occur within a sex cell.
In what situations does a mutation start as a disadvantage or nuetral and then become favourable?
When the organisms environment is changing.
What is selective advantage?
Mutations that help an individual survive.
What is natural selection?
The process by which populations change over time.
What are the 6 distinct ideas of natural selection?
- Overproduction
- Competition
- Variation
- Environmental changes
- Survival of the fittest
- Speciation
What is the idea of overproduction?
More offspring are produced that can possibly survive
What is the idea of competition?
Organisms compete within and between species for limited resources because of overpopulation.
What is the idea of variation?
Inherited differences occur among members of the same species.
What is the idea of survival of the fittest?
Surviving organisms are ones better able to compete, survive, and reproduce.
What is the idea of specitation?
Over numerous generations, new species arise by accumulation of inherited variations of traits; considered new species when member cannot interbreed
How does the enviorment exert selective pressure?
Due to constantly changing environments, individuals that possess variations that allow the to survive in the environmental change will survive and reproduce (survival of the fittest)
What is artificial selection?
Human intervention in the breeding of plants and animals to ensure desirable traits are represtened or magnified in succesive generations.
What are the three types of selection?
- Disruptive
- Stabalizing
- Directional
What is disruptive selection?
The average is disadvantaged.
What is stabilizing selection?
The average has an advantage.
What is directional selection?
One extreme advatage
What are some examples when natural selection is fast?
Quickly reproducing organisms with short life cycles. ex: Bacteria, insects, viruses
Do individuals change within their lifetime?
No
Over what time period does natural selection occur?
Over several generations
How do new traits appear in species?
Mutation
Sexual reproduction
What were the ancient beliefs about species changing?
greek philosophers believed that all life was perfect and unchangeable.
What was Comte De Buffon’s contribution to evolutionary theory?
First to challenge the belief that species were unchangeable
In 1749 he published Histoire Naturelle in which he noted similarities between apes and humans and suggested a possible common ancestor.