B15 Flashcards
Why was Darwin’s theory of evolution not accepted initially?
Most people believed in creation story
Not enough evidence
What was Lamarck theory of inheritance?
That changes during the lifetime of an organism can be inherited
What is speciation?
The formation of a new species, when two populations become so varied they cannot interbreed to produce fertile offspring
Outline the process of speciation through geographic isolation?
Two populations of the same species are separated
Isolation prevents interbreeding
Different mutations occur, different phenotypes
Over time, the two population may evolve and not able to interbreed to produce fertile offspring
Why is genetic variation important in speciation?
Genetic variation produces phenotypic variation, better suited for the environment
How did Mendel study inheritance?
Through carrying breeding experiments on plants
Why was Mendel’s work not recognised until after his death?
He could not explain inheritance, as chromosomes were only discovered after his death
State two kinds of evidence used to show evolution?
Fossils
Antibiotic resistance in bacteria
How do fossils act as evidence for evolution?
Scientists can identify the ages of the fossil and use them to show how organisms change over time
What is extinction?
When there are no individuals of a species still alive
State the factors that may lead to extinctions?
New disease
Predators
Competition
Changes to the environment
What enables bacteria to evolve quickly?
The fast rate of their reproduction
Outline the process of antibiotic resistance bacteria evolving?
Mutation occur in bacteria producing genetic variations
Certain strains are resistant to antibiotics
Resistant strains survive and reproduce
Population of the resistant strains increase
Why are resistant strains of bacteria dangerous?
People have no immunity to them and there is no effective treatment
Why is it difficult to keep up with emerging resistance strains?
Developing antibiotics have a high cost and take a long time to develop
