Life sciences unit 3

define evolution

is the change in the heritable characteristics of biological populations over many generations

what are fossils

fossils are organic remains that have decomposed/been replaced with inorganic minerals which have become buried in mud, volcanic ash, or sediments under specific conditions

fossils are the same size and shape as the living organisms

what is relative dating (for fossils)

age of fossils can be determined by the fossils position in layers

fossils that are younger are closer to the surface

fossils that are older are found farther below

larmarks theory

proposed theory of use and disuse

organisms could change through purposeful use or non use of body parts

thought that physical changes acquired during an organisms lifetime could be passed to offsprings

what are homologous structures

same structure, different function

human arm, bird wing

what are analogous structures

same function, different structure

bird wing, insect wing

what is comparative embryology

comparison of early stages of development among different organisms

embryos that look the same likely came from the same ancestor

what are biochemical relationships

organisms with the same chemical

likely came from the same ancestor

what are heritable characteristics

inherited from genes passed down by parents

how does biogeography influence evolution

the geographical distribution can help us reconstruct evolutionary history

darwin's theory

species evolved over time through the process of natural selection

define natural selection

the process by which organisms with favourable traits are more likely to reproduce

4 steps of natural selection

1. genetic variation within species/population

2. struggle for survival

3. selection-some organisms are better adapted for the environment

4. evolution occurs-change in population over time

the importance of finches

variety in size, colouration, claws, beak shape

different beak shapes allowed finches to eat different foods

thought all varieties of finches came from the same ancestor

developed his theory

define scientific racism

misapplying scientific ideas in order to promote a certain political/personal ideology

are genes or phenotypes inherited

genes

define genetics

study of how genes and traits are passed down from parent to offspring

what is genetic variation

differences that occur in individuals within a species (population)

what does dna stand for

deoxyribonucleic acid