GCSE Biology Edexcel B3 Topic 2

I made these revision notes myself. I got an A* in Biology GCSE and 80 UMS (full marks) in the B3 exam using only these notes.

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B3 Topic 2 Behaviour
Work of famous scientists
Tinbergen and the herring gulls
Niko founded ethology ­ study of animal behaviour. His famous work centred on herring gulls instinctive
behaviour to peck at a red colour to get fed.
Chicks pecked at a red spot more than any other coloured spots as red is on the parents' beak.
Gulls will be fed when they peck at their parents' red beak spot as their parents regurgitate their previously
eaten food!
Lorenz and the goslings
Lorenz was the first behaviourist to document imprinting, a learnt behaviour.
Imprinting is when young animals learn to stay close to the first animal they see, usually a parent so they are
protected and learn species specific behaviour.
Chicks hatched in an incubator would see Lorenz first, thus imprint on him. This is because they do not
recognise adult members of their own species.
Imprinting happens very early on in an animal's life, during the sensitive period, but the learning lasts
throughout life.
Fossey and the gorillas
Dian Fossey was an American zoologist who lived with gorillas in Rwanda for several decades. She
documented, for the first time, the dynamics of gorilla society, their complex family relationships and
communication between individuals.
o She found they worked together to find food, so even more food was found.
o They protected each other from attacks.
o All males in the group had a social rank/hierarchy so everyone knew their place in the group and
prevent fights.
o They groomed each other, which not only kept them clean but reinforced social bonds. They also
showed physical affection towards one another, such as hugging.
Dian imitated gorilla behaviour and was partly-accepted by the gorillas into their family group, allowing her
to document their natural behaviour.
Goodall and the chimps
Jane Goodall lived with chimps in Tanzania in the 1960s and reported their natural behaviour for the first time.
Chimps were observed using tools like a modified stick to obtain termites from mounds. They are one of the
few animals to do this.
Chimps were also seen hunting in a pack, increasing the likelihood of success.
Chimps have a complex group society and communication which had not been observed before her research.
Behaviour: How an animal responds to external stimuli or internal stimuli.
Behaviour centres around a few main things:
o Obtaining food.
o Obtaining a mate and reproducing.
It can be divided into 2 categories:
o Innate
o Learned

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Although, some behaviour is a mixture of the two (such as imprinting).
Innate behaviour
Reflexes ­ life saving
o Iris reflex ­ protects the retina by controlling light coming in.
o Movement of body parts in response to a stimulus.
o Automatic ­ no need to think about them.
o Movement away/towards a stimulus.
o For example, negative phototaxis in earthworms (moving away from light).
o An organism changes the speed of its random movement in response to an environmental stimulus.…read more

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Training animals using conditioning
Humans use both classical and operant conditioning to train animals to do certain things.
Training animals usually involves operant conditioning ­ giving rewards when the animal does something you
want it to do. Punishments can work in reverse ­ when the animal does something you don't want it to do ­
but punishment is not recommended as it is stressful for the animal and rewards work just as ell.…read more

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Polygamous: More than one partner
Examples of:
o Animals that mate for life: swans, bald eagle, albatross, mallard, raven, penguins, parrots
o Animals that have several mates in a lifetime: dogs, hippos, gorillas
o Animals that have many mates per season: lions, wolves, sea lions, cats, rabbits
Animals attract a mate with: plumage tail length with peacocks.…read more

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Co-evolution: where two or more species affect each other's evolution.
An example is milkweed and some species of monarch butterfly and beetle. The milkweeds are fed on by
insects and thus, some milkweeds have evolved to produce foul tasting toxins which stop the insects from
However, some monarch butterflies and milkweed beetles have co-evolved and are able to detoxify the
chemical from the milkweeds and can keep eating the plant.
Another example is the Darwin hawk moth.…read more

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Tools were found with Homo Habilis and Homo erectus. Stone tools cannot be dated directly, but we can
date the layers of rock or sediment they are found in. We assume that the tool is the same age as the later of
rock and sediment.
Age of a tool can also be found by dating the fossils found with the tools, if any. Carbon -14 dating helps to
date any material found with it that is made from carbon e.g. a wood handle.…read more

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Mitochondrial DNA
Mitochondria in all living cells have their own DNA.
The mitochondria DNA is always from the mother as the cytoplasm of the egg cell is the first point of the
DNA changes over time due to mutations, however, mtDNA mutates around 100 to 1000 times faster than
nuclear DNA. This means that over the past 50 000 years many more mutations have happened in the mtDNA.
After death, tissue starts to decay and chemicals in cells break down, including DNA.…read more


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