Genetics and Evolution Flashcards
What is the definition of a species?
a group of organisms that can breed together and produce fertile offspring.
What is the definition of nature?
the basic characteristics of an individual as a result of inherited genes.
What is the definition of nurture
the basic characteristics of an individual as a result of the environment that you live in.
What are two examples of nurture characteristics?
personality and dying hair colours
What are two examples of nature characteristics?
eye colour and nose shape
how are identical twins produced?
one egg is fertilised by one sperm and it is split after fertilisation.
what percentage of DNA do identical twins share?
50%
what do identical twins share as they grow up?
the same environment
what do the twin studies tell us?
they compare environmental and inherited factors and characteristics.
what do twin studies compare?
nature VS nurture
What causes variation in identical twins?
environmental characteristics (nurture)
what causes variation in non identical twins?
inherited characteristics/ genetics (nature)
who created the theory of natural selection?
Charles Darwin
What is a mutation?
a change in genetic DNA
What is variation?
a range of characteristics
What is the technical term for survival of the fittest?
Natural selection
what are the stages of natural selection?
there is variation in a population - the organisms best suited for the environment survive and breed - the others die - the organisms that breed pass on genetic material and are more likely to be successful - this process is repeated and over time species evolve.
what was Lamark’s theory?
the more a characteristic is used the bigger and stronger it becomes - characteristics not used disappear - the used characteristic is passed on to its offspring.
what happens to species unable to compete - Charles Darwin?
they go extinct
What is similar about human and chimp skulls?
the bone structure - same amount of bones and teeth
Which islands where the birds that Darwin saw from?
Galapogus islands
What varied about these birds?
beak size
Which animals survive the longest?
the animals best at surviving and reproducing.
How does speciation occur?
the population becomes seperated into two groups - over time each group evolves differently due to genetic variation - the longer they are seperated the more different they become - eventually the two groups have changed so much they can no longer interbreed.
What are the three isolation methods for speciation to occur?
continental drift - mountain formation - slitting of habitats ( this can be like deforestation or flooding etc)
What happens differently in speciation?
natural selection
what is selective breeding?
speeds up natural selection by selecting animals or plants for breeding that have required characteristics.
what are the limitations of selective breeding?
inbreeding, diseases are prone to some species
What are advantages of selective breeding?
economic gains, reponsible for agricultural progress
