variation and evolution by natural selection Flashcards
what is meant by variation?
variation is all the differences in the characteristics of individuals in a population
what are the 3 main causes for variation in a population?
inherited, environmental and both
what is an example of an inherited characteristic?
eye colour
what is an example of an environmental characteristic?
accent
what is an example of a characteristic that is both environmental and inherited?
height in humans
explain how height in humans is both an environmental and inherited characteristic?
person may have alleles which make them likely to grow taller, however they need a sufficient diet to develop
what is the cause of genetic variation?
mutations
what is a mutation?
mutations are random changes to the dna
most mutations have __ effect on the phenotype?
most mutations have no effect on the phenotype
however, some mutations may have ____ on the phenotype?
however, some mutations may have some effect on the phenotype
very rarely, what can mutation lead to?
very rarely, mutation can lead to a new phenotype
how can a new phenotype become common throughout a species?
if the environment changes and if new phenotype makes an individual more suited to a new environment
what is a phenotype?
the physical characteristics that are observed in an individual
what does theory of evolution state?
all of today’s species have evolved from simple life forms that first started to develop over 3 billion years ago
what is evolution?
change in inherited characteristics of a population over time through a process called natural selection
what is speciation?
when one population of a species have become so different they can no longer produce fertile offspring
