evolution + genetics Flashcards
seminar 1
why is polar bears fur white
allows them to blend in with the environment for protection and to camouflage
what came the first - brown or polar bear
brown bear
how was the brown bear adapted
blend in with environment of greens and browns
how do penguins adapt
white tummies - less obvious when viewed from below
black backs - protect them from above
benefits of human variation
allows people to be distinguished, increases diversity of abilities, interests and perspectives, basis for evolution
limitations of natural selection
makes successful tissue and organ transplants difficult, existence of real differences can allow prejudice or discrimination to occur
what determines colour of skin, eyes and hair and protects skin against UV radiation
melanin
how does melanin protect skin against UV radiation
by controlling amounts of UV from sun that penetrates skin by absorption
Mendel’s results
1/4 white, 3/4 brown
dominant trait
shows in the individual, result in the offspring showing the trait
recessive
only shows if theres 2 recessive traits, passed onto next generation
genotype
traits that an organism can pass onto its offspring through genetic material
phenotype
trait thats expressed
homozygous trait
identical alleles for a trait
heterozygous trait
different alleles for a trait
importance of Mendel (3)
forms basis of genetic inheritance, important in determining inheritance of genetically inherited illnesses, not complex enough to explain inherited behaviours
1875
Hertwig observed process of fertilisation in sea urchin eggs
1879
Flemming discovered rod like structures in nucleus of cell
1883
van Beneden saw separate chromosomes of the egg and sperm merging
1900
de Vries, Correns + Tshcernamk found 3:1 ratio of Mendel and searched out his original papers
1903
Sutton proposed that Mendels factors were located on chromosomes
1953
Watson + Crick discovered DNA
huntingtons disease
dominant
phenylketonuria
1 in 10000 people, 1 in 50 carry recessive gene
