Evolution Flashcards
Why was Darwin’s theory only gradually accepted
At the time scientists didn’t think he had enough evidence to back his theory
What did Lamarck suggest
When a characteristic is regularly used it becomes more developed
= this strength and characteristic is then passed on to offspring
Problem with Lamarck’s idea
Changes that occur in an organism lifetime can’t be passed on to offspring
Darwins theory
Theory of evolution through natural selection
Describe his theory of natural selection
- Within a species, there is a wide range of genetic variation
- Individuals with characteristics most suited to environment
= more likely to survive to breed successfully
How do new species form
- one place where species interbreed
- any beneficial mutation spreads through whole population
- geographical barrier takes place
- separates two populations
= no interbreeding - over time natural selection will favour different alleles
Mendel’s concept
Characteristics aren’t blended during inheritance
= Characteristics are determined by inherited units
= These units do not change when passed onto descendants
= units called genes
Define a fossil
Remains of organisms from millions of years ago, which are found in rocks
How can fossils form
- when parts of organisms haven’t decayed
- if parts of organism slowly replaced by minerals during decay process
- can be the preserved traces of organisms
Problem with fossils
Many of the earliest forms of life with soft- bodied organisms
= very rarely form fossils
= many fossils that did form have been destroyed by changes to rocks in earths crust
= can’t be certain of how life on earth began
Reasons for extinction
- due to a catastrophic event
- environment changes
- new disease or predators eats all species
Uses of antibiotics
- medicine
- killing bacteria
- farming to prevent animals from developing bacterial diseases
How does antibiotic resistance happen
- mutations
How to reduce anti biotic bacteria
- Doctors should not prescribe antibiotics inappropriately
- Patients should make certain to complete the course of antibiotics
- Restrict the use of antibiotics in farming
Problems with making new antibiotics
- extremely expensive
- takes a long time