B6 COPY Flashcards
What is natural selection?
The process in which organisms become better suited to their environment due to random mutations.
Give an example of natural selection?
All rabbits had short ears
One day a mutated gene meant one rabbit had big ears
This rabbit could hear better therefore avoid predators
The offspring all had big ears and before you know it all the rabbits had big ears.
What is evolution?
Evolution is the change in inherited characteristics of a population over several generations, through the process of natural selection.
The speed at which an species evolves depends on how quickly it evolves.
How does observation of fossils provide evidence for evolution?
Fossils can tell us what an organism looked like.
By arranging fossils in chronological order, we can see how its appearance has evolved
What are fossils?
Any trace of an animal or plant which lived long ago.
How can bacteria show evolution?
Bacteria randomly mutates which introduces new variants into the population.
-these can lead to changes in the phenotype which could cause it to become less affected to an antibiotic.
If you have 2 bacteria with a resistance variant and 2 without, the 2 with the variant will survive and produce offspring.
What is selective breeding?
Mating the best organisms to get good offspring.
What characteristics do organisms require to be selective breeded?
- Maximum yields of stuff e.g.meat and milk.
- Good health and disease resistance
- Good qualities like speed and fertility.
What are the negatives of selective breeding?
Causes a reduction in the gene pool as many of the best organisms are part of the same family.
Inbreeding can lead to health problems when the gene pool is limited
As there is not much variation in the population ,a new disease can be deadly.
Who discovered evolution by natural selection?
Charles Darwin
What did Darwin do to discover evolution?
He made observations about fossils and living organisms
He noticed there was variation in the same species
-those most suited to their environment would survive.
He carried out selective breeding to show how a selection of particular characteristics could lead to genetic variants.
Who was Wallace?
A scientist who proposed that evolution could lead to new species entirely.
How has ideas about evolution influenced modern biology?
We now know mutations cause genetic variants
We now know the importance of finishing a set of antibiotics
Classification
Conservation of species
What are the advantages of asexual production?
Can reproduce very quickly
Only one parent required
Can colinise a new area rapidly
What are the disadvantages of asexual reproduction?
No genetic variation so all organisms could be affected
Environmental conditions could affect whole population
What are the advantages of sexual reproduction?
Genetic variation ,so if the environment chnges some organisms will be able to cope
Evolution over time which allows them to be better adapted to their environment.
What are the disadvantages of sexual reproduction?
More time so fewer offspring
Two parents required.
What is classification?
Organising living organisms into groups.
How are organisms classified?
DNA sequecing-similarities
Similar numbers of genetic variants
What do evolutionary trees show?
Show how species are related to each other.
What does biodiversity depend on?
- variety of organisms living in an area
- diversity of genes and alleles
- diversity of ecosystems in a particular area
What human interactions can reduce biodiversity?
- increasing human population
- industrialisation
- globilisation
- Habitat destruction
- Waste
- Sharing resources
What is sustainability?
Meeting the needs of today’s population without harming the environment or using up resources the future generation will need.
What conservation techniques can we use?
- Protecting specific species
- Protecting habitats and ecosystems
- Preventing ecosystem damage
How can a change in availability of WATER affect organisms?
When rainfall patterns change, organisms may go to a place where there is more water.
How can change in GASES affect organsims?
So species can’t grow in areas where there is air pollution.
How does maintaining biodiversity benefit wildlife and humans?
- Protects food supply
- Ensures minimal damage to food chains
- Provides future medicine
- Provide industrial materials
What are the economic issues with maintaining biodiversity?
-Can be expensive to conserve species or habitats
What are the moral issues with maintaining biodiversity?
- Some people believe it has no affect for humans
- Some believe that it is wrong to stop people in developing countries using natural resources which could benefit their economy
Why doesn’t everyone have food security?
- Environmental change
- Changing diets in wealthy populations
- New pests and pathogens
- Unsustainable methods of producing food
- Costs of products
What methods are there for improving food security?
- Improved nutrition
- Control of pests
- Protection against pathogens
- Plant hormones
- Selective breeding
