2.6 - Evolution Flashcards
Who proposed the theory of evolution?
Alfred Russel Wallace
Who did Alfred Russel Wallace admire?
Charles Darwin
What was Wallace best known for studying?
Warning colouration in animals (golden wing butterfly) as well as his theory of speciation.
What is Wallace’s theory of speciation?
The formation of new and distinct species in the course of evolution
What was the idea behind the theory of evolution?
Through the process of natural selection all species of living things have evolved from simple life forms over a period of time.
What does natural selection mean?
The best adapted individuals survive longer, have more off spring and thereby spread their characteristics. AKA survival of the fittest.
Individuals in a species show a wide range of variation as a result of…
differences in their genes caused by random mutations
In every population more offspring are produced than can survive. Overproduction leads to…
Competition (e.g. food)
If two populations of one species become increasingly different in phenotype that they can no longer interbreed to form fertile offspring then what has been formed?
Two new species
What causes new strains of bacteria to form that are resistant to antibiotics?
Mutations
What are the four main steps of the development of antibiotic resistance?
1) Random mutations occur in the genes of bacterial cells
2) Some mutations protect the bacteria from the effects of the antibiotic
3) Bacteria without the mutation will die or become unable to reproduce
4) Resistant bacteria can reproduce with less competition from normal bacteria strains
How do you reduce the rate of development of antibiotic resistant strains?
Doctors shouldn’t prescribe antibiotics inappropriately.
Patients should always finish their full course of. antibiotics to ensure all bacteria are killed and none survive.
The agricultural use of antibiotics should be restricted.
Why have scientists stopped discovering new antibiotics?
Expensive
Takes time to develop
When does extinction happen?
When no remaining individuals of a species are left alive. Animals that have not adapted to their environment are more likely to become extinct than those who have.
What are the causes of extinction?
New diseases
New predators
New more successful competitors
Changes to environment over time (climate change)
A single catastrophic event (volcanic eruption, asteroid)
