human bio evolution test

4 factors effecting fossil formation

soil PH- bones found in alkane soil.

climate- humidity, rainfall, temperature.

soil moister - promotes microorganism activity

oxygen level, low oxygen inhibits the activity of microorganisms.

5 reasons to why fossils are difficult to locate

fossils may be in remote locations

in sedimentary rock or deep in the ocean.

or encased in volcanic lava.

destroyed due to erosion or weathering.

human activity.

half life of carbon 14

5730 years

half life of K-40

1.3 billion years.

limitation to pottasium argon dating 3

cant date actual fossils, only ignous rocks arround the fossil.

cant date rocks older than 200000 years.

only relevant for igneous rocks.

limitation for carbon 14 dating

cant date fossils less that 600 000 to 700 000 years

must be organic material such as tissue bone, facies, wood

bipedal with a striding gait

refers to walking on 2 feet with the hip and knee bieng fully extended.

why has prognathism reduced

due to smaller teeth, development of chin and nose

dental formula for hominids

2:1:2:3

endocasts

can be used to determine the shape of the brain surface. it is an impression of the inside of the skull made from rock or other solid material

cranial capasity- what is it and how is it mesured

• is the volume of the cranium that houses the brain.

• mesured by endocasts

how can we mesure brain size in early hominins

• by mesuring the cranial capasity using endocasts.

what is a diastema

the gap between the upper 2nd insisers and the upper canine to accomidate for the larger lower canine allowing for the mouth to close.

what is a fossil

any preserved remains of somthing that was living or presertved remains that showed somthing was living

artifact

an object that is made by humans. e,g stone tools, carvings, cave paintings.

index fossil

from an organism that was geographically widly distributed, and were only on earth for a short period of time. they are usefull for correlating rock strata, for one area with another.

relitive dating

the comparrison of fossils to tell weather one sample is younger or older than the other. usefull in determining the sequence of events.

absolute dating

determining the actual age of fossils in years.

phylogenic trees

are a diagramic representation of the evolutionary relationship between groups of organisms that have derived from a single common ancestor. they are simple representations of complex relationships.

what is the principal behind radioisotope method of dating.

radioactive material decays at a known rate, radioisotope based on knowing the half life of the isotope. by knowing how much radioactive product is in fossil and knowing the rate of decay, allows age of the fossil to be calculated.

tissues best preseruved in

little to no oxygen

wet acidic soil