Evolution of Species Flashcards
What are mutations?
Spontaneous, random changes to the genetic material of an organism, this means the order of the bases in DNA is different or the number or structure of chromosomes are different.
What are mutations the only source of?
New alleles
What happens if the order of bases is different?
This may result in a change of the protein structure coded by the DNA
What can a tiny change to a vital gene do?
Prevent an important protein from being built correctly
When can mutations be serious?
They can be serious depending in where the mutation occurs
What are gene mutations?
Miniscule mutations that affect the base sequence of DNA
What are chromosome mutations?
Large scale mutations which can increase or decrease the chromosome number or can change the structure of a chromosome
Why are mutations important?
They are the only source of new alleles in a species, the source of variations which can be crucial for survival
Give environmental factors of mutations
Radiation (this includes gamma rays and UV rays) and chemicals (this includes agent orange, bromine and nicotine)
Why is adaptation important?
New alleles that are produced by a mutation that can cause an organism to change.
If these changes are an advantage to survival then the organism becomes better adapted to their environment.
What is adaptation?
An inherited characteristic that makes an organism well suited to surviving in its environment/niche
What are the three types of adaptations?
Physiological
Structural
Behavioural
Name the four steps of natural selection
Species produce more offspring than the environment can sustain
Natural selection or survival of the fittest occurs when there are selection pressures
The best adapted individuals in a population survive to reproduce, passing on the favourable alleles that confer the selective advantage
These alleles increase in frequency within the population
What is natural selection?
Natural selection is the process through which populations of living organisms adapt and change.
What is selection pressures?
Anything from list of abiotic and biotic factors impacting biodiversity
Give examples of selection pressures
Changing environment (temperature, light, PH)
Introduction of disease
Change in predators/grazing
Introduced species
Competition
What can be used to explain high speed evolution of insecticide resistance in mosquitos?
Natural selection
What is speciation?
A process forming two or more species from one original
What is a species?
A group of organisms that can reproduce with one another in nature and produce fertile offspring.
Explain the four step by step of speciation
After part of a population becomes isolated by an isolation barrier, which can be geographical, ecological or behavioural.
Different mutations occur in each sub-population.
Natural selection selects for different mutations in each group, due to different selection pressures.
Each sub-population evolves until they become so genetically different that they are two different species.
What do geographical features such as rivers, deserts, oceans and mountain ranges do?
Isolate groups
When do ecological isolation barriers occur?
2 sub-populations live in the same area and could technically meet and breed, but they don’t as they live in different areas of the habitat
Give examples of ecological isolation barriers
Hot and cold areas of the habitat
Humid and dry
Different Ph (different soil types)
Salinity
Altitude
When does behavioural speciation occur?
When 2 sub-populations live in the same area, and could technically meet and breed, but don’t due to changes in behaviour
Give examples of behavioural speciation
Different courtship behaviours
Diurnal/nocturnal
What are the four steps of speciation?
Isolation
Mutation
Natural selection
New species
What does each sub-population have?
It’s own gene pool
What happens even if the two populations are joined together?
They will not be able to produce fertile offspring
