Biology GCSE Edexcel B1 Topic 1

I made these revision notes myself for when I was studying for GCSEs. I got an A* in Biology and 72 UMS in B1 by just using these notes.

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Classification, variation and inheritance B1 Topic 1

Scientists group organisms by looking at all the characteristics of each organism. Organisms with many
characteristics in common are grouped together as a species.
Different species that share many characteristics are grouped as a genus (plural genera). Genera that share
many characteristics…

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Organisms can be characterised based on how they reproduce.
External fertilisation ­ adult female releases her eggs in water and are fertilised by sperm released by an
adult male.
Internal fertilisation ­ takes place inside the female's body.
Oviparous ­ lays eggs (many vertebrate do this)
Viviparous ­ give…

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An organism's scientific name has two Latin words, genus and species. This is called the binomial system.
Organisms that share the first word in their name are closely related. Scientists can tell from the name
whether two organisms are closely related.
The binomial system is useful in cases where organisms…

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Genetic variation

All plants and animals have characteristics that are in some ways similar to their parents'. This is because an
organism's characteristics are determined by the genes inherited from their parents.
Most animals, and significant numbers of plants, get some genes from the mother and some from the father.…

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Polar bears and penguins have adapted to living in the cold, freezing conditions of the Arctic and Antarctic.
Polar bears have:
o A compact shape which gives them a small surface area compared to volume which reduces heat loss.
o A thick layer of blubber for insulation which also acts…

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Darwin knew there was competition between individuals. He also knew that pigeon breeders selected birds
with certain characteristics to breed which meant that those characteristics were inherited by the offspring.
Darwin realised that if the environment changes then different variations may be better suited to the new
conditions. Individuals with…

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Recessive allele: Version of a gene that will only have an effect if the dominant version of the gene is not
present (if both are present)
Homozygous: both alleles for a characteristic are the same the organism is homozygous for that
Heterozygous: if both alleles for a characteristic are…

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Specific genetic disorders

Genetic disorders are diseases which are caused by faulty alleles. The allele for sickle cell anaemia is
recessive so two copies are needed to suffer from the illness. Sickle Cell Anaemia is bad as the red blood
cells do not function properly and they stick together and…




This  a very detailed set of notes on classification, variation and inheritance which could be used not only for the Edexcel specification  but also in parts for the other biology specifications. Understanding of the key terms could be checked using the recommended flashcards.

fran morris


Wow this is brilliant thankyou so much!

James Webb


Thanks, this is brill!



Thanks! Hopefully the B1 exam goes well on Tuesday!



This is so AMAZING!! Thank you so much!!!



im in year 9  and i was just wondering what is b1, AQA or edexcel mean ? 



b1 is core science and aqa and edexcel are different exam boards



pretty lit



This Website is probably the best Revision recourse I have actually used and has helped me I have an exam for this topic next week. Im sure I will be able to understand most the exam ith using this revision website. THANKS!!! :)

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