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Flashcards in Human evolution Deck (26)
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1
Q

what factors have effected human physiology

A

natural disasters effected evolution

species development slightly due to adaptation to climatic conditions

2
Q

what happened to make humans dominant

A

cooking gave humans advantage
- requires fire
some toxins in fresh foods

3
Q

was selection of the fittest the reason for human dominance

A

difficult to validate

4
Q

what is an example of toxins in fresh food

A

cassava - staple for millions S America, Africa

many African cassava contain cyanide, toxic unless processed correctly

5
Q

how is cassava processed properly

A

cut roots small pieces
boil in open pan - dont stand over it as HCN blinds
leave 2-3days so HCN volatilise

6
Q

what causes toxins in cooked foods

A

heat causes significant chemical change - creates some molecules known to be toxic

7
Q

what is an example of toxin produced when food is cooked

what is it produced from

A

acrylamide

from amino acid asparagine (potato contains this)

8
Q

what are the benefits of eating raw meat and plants

A
high vitamin levels
higher fibre content
pick and eat 
weight loss
modern raw food has oil - responsible for 30% energy
9
Q

what are the cons of eating raw meat and plants

A
lot of chewing - lot energy used 
digestion difficulty - lot energy used
high bacterial load
pathogens
toxic compounds
short shelf life
seasonal availability 
33% chronic energy deficient
10
Q

what was the effects of cooking food on the physiology of ancient humans

A

chewing - delivered small particles to stomach so less energy and less time
digestion of protein and polysaccharides improved
starch gelatinised - easier amylase digestion, more energy release
proteins more soluble, smaller food = easier protease digestion, more efficient nutrient uptake
longer shelf life

11
Q

what causes a longer shelf life on cooked foods

A

smoke presence
lower water activity
decreased microbial load

12
Q

what is the effect on collagen when cooked

A

triple helix structure unwinds

form gelatin which is water soluble and nutritious

13
Q

what is the effect on fat when cooked

A

fat soluble vitamins dissolved in oil droplets in food
protects vitamins from oxidation
assits gut uptake

14
Q

what is the effect on pathogenic bacteria when cooked

A

heat 72 degrees+

decrease microbial load

15
Q

what is the effect on plant tubers when cooked

A

softens the many hard roots by hydrating the tissue and modifying cell walls

16
Q

what is the effect on starch when cooked

A

gelatinises starch, easier to break amylase in the gut, increasing sugar supply

17
Q

what is the benefit of cooking water

A

make use of soluble vitamins

18
Q

what are the benefits on cooked food

A

more energy to hunt and gather food
increase fertility
time to relax - sheep and cows eat grass most of day for enough

19
Q

how quickly do species react to environmental changes, example

A

Darwin studied finches in Galapagos islands (develop his theory of evolution)
islands separated from other species, easy measure effects of environmental change
e.g. drought, relied on hard-shelled seeds so bigger stronger beaks favoured, survive

20
Q

what are the anatomical changes to mouth and teeth that have occurred due to eating cooked foods

A

more need for molars, less for sharp teeth
high energy food = less food entering more
fossil and archaeological records = decreasing mouth size, teeth size and type change

21
Q

what are the anatomical changes to the digestives system that occurred due to eating cooked food

A

cooked food provide more energy - smaller meal, human stomach small for out weight
large intestine about 60% of that expected - where intestinal microbes break fibrous materials like resistant starch and non-starch polysaccharides
amylase more important due to increased gelatinised starch

22
Q

which part of animal contains most energy

A

liver kidneys

most energy in fast way

23
Q

what did homohabilus do for safety

A

slept in trees

was a climber

24
Q

what did homoerectus do for safety

A

not strong enough arms to climb

had fire to scare

25
Q

why did the brain size in homoerectus increase

A

brain needs lot energy
spare energy - brain develop
brain makes up 2.5% body but uses 20% of basal metabolic rate

26
Q

what are examples of challenges ahead for human physiology and environment

A

obesity
feed ever growing population
antibiotic resistance