variation Flashcards
what did Mendel do with pea plants
crossbreeded yellow and green pea plants which produced only yellow plants and breeded these to get 3/4 yellow and 1/4 green
what did he determine was being passed on from 1 generation to the next
hereditary units which could be recessive(and only expressed if plant got the unit from both parents) or dominant
what are alleles
Alternative forms of the same gene
what is a genome
entire set of genetic material in an organism
what is a gene
segment of dna that codes for a particular type of protein
what are alleles
different versions of the same gene
what is the genotype
collection of alleles we have
phenotypes
the characteristic we get from the genotypes
what causes variation
phenotypes-from genes and environment
genes individuals inherit
what people may have the same genome
identical twins
what are the different environmental factors for genes
smoking
alcohol
lifestyle
exercise
what is a mutation
change in the dna code which may change protein therefore phenotype
what is an example of a positive mutation
lung disease resistance
ability to run faster
how are beneficial mutations passed on
organisms that have them are more likely to survive and therefore more likely to produced
who made survival of the fittest
darwin
who made natural selection and what is it
fittest individuals selected to survive made by Darwin
what is evolution
inheritance of certain traits could lead to whole new species or change in it over multiple generations
what is Lamarcks theory
organisms could acquire new traits in their lifetime and these could be passed to their offspring
Describe a series of events that might result in zebras evolving to run more quickly.
There is variation among the zebra population so that some can run faster than others
A mutation arises that allows some zebras to run faster
Those zebras that can run fastest are more likely to survive…
…and are therefore more likely to reproduce and pass on their advantageous alleles
This repeats over multiple generations
So the advantageous allele spreads throughout the population, until the species has ‘evolved’ to run faster
how was Lamarcks theory disproved
characteristics gained by an organism in its lifetime do not affect the dna sequence of an organism and arent passed down
what was darwins 1st observation
organisms within species show wide variation for a specific trait
what was darwins 2nd observation
there is variation between species adapted to different environments
what was darwins 3rd observation
older rock layer had organisms which less complex fossils-more recent more complex
1st similarity between darwin and lamarcks theories
some organisms have diff traits due to variation
what is 2nd similarity between darwin and wallaces theory
organisms with the advantageous trait are better adapted to the environment
what is the 3rd similarity between darwin and lamarcks theory
organisms with the avantageous trait are more likely to survive and reproduce passing on trait
what is the last advantageous trait
over many generations organisms now have the advantageous trait
what was the 1st reason darwins theory wasnt initially accepted
-challenged religious belief that God created all life
what was the 2nd reason darwins/lamarcks theory wasnt initially accepted
lack of evidence made scientists wary of accepting it
what was the 3rd reason darwins theory wasnt initially accepted
dna was undiscovered/mechanism for inheritance and variation was unknown in Darwin’s time
