Natural Selection and Genetic modification

Biology.

Natural Selection

The process by which organisms evolve due to mutations and survival of the fittest

Process of natural selection

Species has genetic variation due to mutations

Selection pressure occurs

The better adapted organisms survive, reproduce and pass on the advantageous genes

Continues over several generations, eventually the majority of the population will have those advantageous genes

MRSA Bacteria - proving Evolution

MRSA bacteria became resistant to antibiotics, as they had mutated a gene giving them this. When antibiotics were introduced around them, they survived and divided, passing on the resistance genes, while other bacteria died. The whole population is now resistant to the bacteria.

Ardi

Ardipithecus Ramidus. Found 4.4 million years ago, had a smaller brain, longer arms, shorter legs but long enough legs and slightly arches feet to suggest the ability to walk upright, still had big toes

Lucy

Australopithecus Afarensis. Had longer leg bones and shorter arms than Ardi, lacked Ardi’s big toe for climbing, had a larger skull volume than Ardi. Was a lot more capable of upright walking than Ardi.

Turkana Boy

Fossil discovered 1.6 million years ago. Had a larger skull volume than Lucy, had longer leg bones and shorter arms. Mostly if not always walked upright.

Stages of human tool development

Homo habilis, 2.5 - 1.5 million years ago, hit rocks against each other to create sharper edges which would be used to scrape meat off of bones

Homo erectus, 2.0 - 0.3 million years ago, created sharper and more defined edges for scraping meat and opening bones

Homo neanderthalensis was more recent and used flint spears and arrowheads, which were even carved to have hilts to attach sticks on to

Homo sapiens, us, developed metals, and then came sickles, fishing poles, and all of the inventions we use today.

Dating stone tools and fossils

Carbon dating which uses C-14 concentration to determine how old something is, and stratigraphy which uses the rock layer the fossil or tool was found in to date it.

The pentadactyl limb

An arm limb shared by many organisms such as humans, whales and birds. It has 5 digits, a humerus, radius and an ulna, suggesting a common ancestor. However, they are all different, resulting from mutations and selection pressures

Three domain system

System that would split things into three domains before the 5 kingdoms: Eukarya (organisms with membrane bound organelles), Bacteria (organisms without membrane bound organelles) and Archaea which although have no membrane bound organelles, seem to share DNA more similar to the Eukarya. Genetic analysis and further microscopy led to this classification.

Selective breeding

Process by which plants and livestock are chosen and selectively inbred for the best characteristics that would be the most profitable.Pr

Process of selective breeding

Pick 2 parent organisms with desirable characteristics, breed them

Breed offspring who best represent the desired characteristics

Repeat over several generations

Advantages of selective breeding

One of the cheapest and quickest ways to optimise profits with animals

Can help with food security and demand around the world

Disadvantages of selective breeding

Causes the gene pool to decrease in size, can lead to the prevalence of genetic diseases. Inhumane and can also just kill them.

How to culture plant cells

Use autoclaved agar plate and inoculating loop passed over a Bunsen flame to place extracted plant meristem cells onto a growth medium. Allow the plant to grow into a seedling and pot it to grow

How to culture animal cells

Use enzymes to separate extracted cells

Culture them in a liquid medium

Use more enzymes to split the cells up again

Culture these cells and they can be used for preclinical trials etc.

Genetic modification

The process by which the genes of an organism are edited to have the organism show characteristics it wouldn’t normally do. Can be used to create resistant crops or increase the nutrition of crops or animal milk / meat.