unit 2 evolution Flashcards
charles darwin
wrote the book on the origin of species by means of natural selection which had two points organisms present today are descendants of ancestral species that were different and the mechanism for evolution is natural selection. sailed HMS beagle and went to the galapagos islands 3 tortoises on different islands and had adapted to the vegetation on their own island. and finch- beaks- different seeds
darwins theory
- individuals differ
- organisms produce more offspring than can survive (over -production)
- struggle to survive ( competition since not all can live)
- best adapted = survival (fitness)
- organisms past best adapted traits to offspring
- this is process of natural selection=change
- species today are descendants with modification
james hutton and charles lyell
age of earth- must be millions of years old. geological processes shaping earths surface are very slow
jean baptiste lamarck
living things change. species descend from others. organisms adapt in their life time with selective use and disuse organisms gained or lost traits in life time if they used them a lot and they would pass that trait on to their offspring.
thomas malthus
population to big gunna keep growing and darwin thought this applied to plants and animals even more.
evidence of evolution
fossil record- species come and gone evolving into new ones fossils have changed
geographic distribution- similar species in different locations. different animals on different continents had similar behaviour because they have the same ancestor
homologous structures- same types of bone or muscle used for different things. evolve to use structure in different ways
embryology- embryos develop similar at early stages for some species resulting in homologous structures similar genes = similar development
vestigial structures- remnants of evolutionary heritage FROM THE PAST. unused bones and such.
dating fossils
relative dating- looks at fossil record- fossils in order shows change in organism.
absolute dating- carbon dating- age in years uses the amount of radio active isotopes present or not present
miller and urey
produced amino acids through passed sparks ( lightning) through a mixture of gases like NH3 H20 H2 CH4 that resembled earths early atmosphere and created amino acids the building blocks of life
proteinoid microspheres
tiny non living bubbles that have similar properties to living this- semipermeable membranes and they stored and released energy.
endosymbiotic hypothesis
2 billion years ago prokaryotic cells began to evolve internal membranes and other prokaryotic cells enter them and began living in them with a symbiotic relationship
traits
features inherited at conception
homozygous vs heterozygous
homozygous same gene BB bb
heterozygous different genes Bb
phenotype
outward appearance of gene
monohybrid crosses
one gene pair that is studied and the rest of the traits are ignored
gregor mendel
father of modern genetics and realized that characteristics and repeated and the passing of traits is heredity
genes
units of nucleotide base pairs that instruct cells to produce specific traits
alleles
two or more alternate forms a gene
dominant alleles
determine the expression of genetic trait
recessive alleles
masked by dominant alleles.for them to show there must be two of the same recessive genes
genotype
refers to genes of a trait for an organisms BB Bb bb