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Natural Selection and Evolution - Coggle Diagram
Natural Selection and Evolution
The Theory of Evolution
The theory of Evolution suggested that characteristics, especially alleles, that are more likely to survive will be passed on, and characteristics that are not favourable will be forced to evolve or die out.
The theory of Evolution has been backed up by recent findings such as the presence of Anti-Biotic resistant bacteria like MRSA. MRSA developed antibiotic resistance due to their exposure to antibiotics, which could force them to develop genes that allow them to live
Human Evolution
Ardi - 4.4 million years ago
Lucy - 3.2 million years ago
Leakey's Discovery of fossils, dating 1.6 million years ago
There is evidance for human evolution in the use of Stone tools
Older rock layers are usually found below younger layers of rock, using this information about the use of stone tools, and therefore the way that humans have developed.
More Evidance for Human Evolution
The Pentadactyl limb
This limb is a commonly found limb that is found in many species, this shows that those animals with this limb like bats share a common ancestor.
Classification
Genetic Classification works by looking the base sequence of DNA bases to determine how close they are to other organisms,
This is done using RNA sequencing
This new classification system suggests that there are 3 larger domains before kingdoms
Bacteria
Contain True Bacteria
Eukarya
Contain organisms like protists, animals, plants and fungi
Archaea
Organisms that look similar to bacteria but are very different and are usually found in very extreme places, like salt lakes and hot springs
Selective Breading
The process in which organisms with favoured characteristics are bread with other characteristic, until the entire population gains those favoured characteristics.
Organisms can be selectively bread for more useful characteristics
Animals that produce more milk or meat
Plants to produce bigger fruit
Problems with Selective Breading
Reduces the Gene Pool
Inbreeding can cause genetic defects
Lack of Genetic Variation could mean a new disease could kill an entire population
Genetic Engineering
Modifying an organism's genome to produce organisms with favoured characteristics
This can be done using enzymes to cut and join DNA together
These are done in 4 key steps
Ligase joins pieces of DNA together to make recombinant DNA
Recombinant DNA is inserted into the new cell
Vector DNA and DNA that is being insert have sticky ends, which are mixed together in ligase enzymes
DNA that is desired is cut out using an restriction enzyme
Disadvantages of Genetic Engineering
GM Crops or even normal crops won't be able to survive if there is bad soil
Countries may depend on GM soil
Advantages of Genetic Engineering
Crops can be genetically engineered to be resistant to insects
This reduces the amount of pesticides used
Can provide more food for the rapidly increasing population