Overview

• Natural selection is the survival of the fittest, where animals that are better suited to the environment survive and those that are not die off.
• The first stage of natural selection is variation naturally within a species, where there are differences due to genetics and the environment.
• Inheritance then happens, where these good characteristics are passed down to offspring.
• Evolution happens when all of the animals that are not suited to the environment die off, so that the whole species ends up being the ones that are adapted.
• Two scientists, Darwin and Wallace, came up with the theory of evolution, with Darwin investigating evolution in animals and Wallace investigating evolution within plants.
• Bacteria can provide evidence for evolution, as they randomly develop mutations in their DNA and this is that variation we spoke of earlier.
• Human fossils can also provide evidence for evolution, with the oldest human fossil named Ardy suggesting that our ancestors walked upright like humans, but were still ape-like.
• The next fossil, Lucy, is much more adapted to walking and has these arched feet that can really help it walk just like a human, becoming less ape-like.
• The next two fossils were discovered by scientists called Leaky, with these fossils having very short arms and much longer legs to help them walk, suggesting that humans have begun to evolve.
• The pentadactyl limb can also provide evidence for evolution, as it is a limb with five parts, with different animals having this pentadactyl limb but using it for different purposes.
• There are five kingdoms to classify all living things: animals, plants, fungi, prokaryotes, and protists.
• Once sorted into their kingdoms, organisms are sorted through loads of different groups all the way down to their species based on the visible traits.
• The system of classifying organisms based on visible traits is now outdated as genetic analysis can be used to look at the sequences of their DNA and determine their relatedness.
• The three domain system includes Archaea, Bacteria, and Eukarya, which are much broader groups than the five kingdom system.
• Selective breeding is the process of breeding two parents with characteristics that the offspring will have.
• The problem with selective breeding is that it reduces the gene pool as lots of animals are closely related.
• Tissue culture can be used to clone a plant by growing cells from a small part of a plant off on a growing medium.
• Genetic modification is the process of changing the genome by combining genes from two different organisms.
• The insulin gene is often used in genetic modification as it is a common gene that is useful in many different organisms.
• Genetic modification is expensive, can cause health problems in the animals, and the gene that has been put into the animal could get out into the environment, meaning that super animals who are resistant to loads of different things and can't be destroyed could be created.