6.3 Genetics and evolution (Combined) Flashcards
State two kinds of evidence used to show evolution
● Fossils
● Antibiotic resistance in bacteria
How are fossils formed?
Parts of organisms that have not indicated due to conditions needed for decay being absent
Parts of organisms that have been replaced by minerals as they decayed e.g. bones
Traces of organisms are preserved, covered in sediment and becoming rock
Why are there few traces of early life forms left behind?
Early life forms were mostly soft bodied
How the fossils act as evidence for evolution?
Scientists can identify the ages of the fossils and use them to show how organisms change over time
What do branches in evolutionary trees indicate?
Where speciation has occurred
What is extinction?
Where there are no individuals of a species still alive
State the factors that may lead to extinctions
● New disease
● Predation
● Competition
● Changes to the environment
● Catastrophic events
What enables bacteria to evolve quickly?
The fast rate of their reproduction
Outline the process of antibiotic resistant bacteria evolving
- Mutations occur in bacteria producing genetic variation
- Certain strains are resistant to antibiotics and are not killed when the antibiotic is applied
- Resistant strains survive and reproduce
- Over time, the 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
State an example of a resistant strain of bacteria
MRSA
What can be done to reduce the rate of development of antibiotic resistant bacteria?
● Refrain from inappropriately prescribing antibiotics e.g. for viral diseases
● Patients should complete the prescribed course of antibiotics
● Restrict agricultural uses of antibiotics
Why is it difficult to keep up with emerging resistant strains?
Developing antibiotics have a high cost and take a long time to develop
