Human evolution

Question 1

what factors have effected human physiology

Answer 1

natural disasters effected evolution

species development slightly due to adaptation to climatic conditions

Question 2

what happened to make humans dominant

Answer 2

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

Question 3

was selection of the fittest the reason for human dominance

Answer 3

difficult to validate

Question 4

what is an example of toxins in fresh food

Answer 4

cassava - staple for millions S America, Africa

many African cassava contain cyanide, toxic unless processed correctly

Question 5

how is cassava processed properly

Answer 5

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

Question 6

what causes toxins in cooked foods

Answer 6

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

Question 7

what is an example of toxin produced when food is cooked

what is it produced from

Answer 7

acrylamide

from amino acid asparagine (potato contains this)

Question 8

what are the benefits of eating raw meat and plants

Answer 8

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

Question 9

what are the cons of eating raw meat and plants

Answer 9

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

Question 10

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

Answer 10

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

Question 11

what causes a longer shelf life on cooked foods

Answer 11

smoke presence
lower water activity
decreased microbial load

Question 12

what is the effect on collagen when cooked

Answer 12

triple helix structure unwinds

form gelatin which is water soluble and nutritious

Question 13

what is the effect on fat when cooked

Answer 13

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

Question 14

what is the effect on pathogenic bacteria when cooked

Answer 14

heat 72 degrees+

decrease microbial load

Question 15

what is the effect on plant tubers when cooked

Answer 15

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

Question 16

what is the effect on starch when cooked

Answer 16

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

Question 17

what is the benefit of cooking water

Answer 17

make use of soluble vitamins

Question 18

what are the benefits on cooked food

Answer 18

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

Question 19

how quickly do species react to environmental changes, example

Answer 19

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

Question 20

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

Answer 20

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

Question 21

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

Answer 21

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

Question 22

which part of animal contains most energy

Answer 22

liver kidneys

most energy in fast way

Question 23

what did homohabilus do for safety

Answer 23

slept in trees

was a climber

Question 24

what did homoerectus do for safety

Answer 24

not strong enough arms to climb

had fire to scare

Question 25

why did the brain size in homoerectus increase

Answer 25

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

Question 26

what are examples of challenges ahead for human physiology and environment

Answer 26

obesity
feed ever growing population
antibiotic resistance