Binomial system
A system for naming species which uses two Latin words.
Evolution
The gradual change in the characteristics of a species over time
Arid
Human like species. Around 1.2m and 50kg. Very long arms and long big toes on the sides of her feet.
Lucy
1.07 m tall. Curved toes like modern day humans.
Homo habillis
Quite short with long arms.
Homo erectus
1.79m and strongly built
Order of human like species
Ardi, Lucy, Homo habillis, Homo erectus, Homo sapiens.
How do scientists find out how old fossils are?
By testing the age of the rock around the fossils.
Genetic variation
The characteristics of individuals vary due to differences in genes
Natural selection
The variations of some individuals make them better at coping with change than others, and therefore more likely to survive (survival of the fittest)
Artificial selection
When humans choose certain organisms because they have useful characteristics, such as sheep with thick wool.
Selective breeding
Breeding animals with similar characteristics so their offspring has those chosen characteristics, therefore increasing the abundance of species with specific characteristics (e.g thicker wool, a darker colour etc.)
Why are plants and animals selectively bred?
- Disease resistance
- Yield
- Coping with certain environmental conditions
- Fast growth
- Flavour
Genetic engineering
Genetic engineering involves changing the DNA of one organism often by inserting genes from another. This creates genetically modified organisms (GMOs)
Genetic engineering of bacteria
- Restriction enzyme make staggered cuts in DNA molecules creating sections with unpaired bases at the end
- Restriction enzymes then cut plasmids open. By using the same enzyme, the plasmids have the same sticky ends
- Sections of DNA containing the insulin gene are mixed with the cut plasmids. The complimentary bases on the sticky ends pair up (with the use of ligase)
- The plasmids are then inserted back into bacteria, which are grown in huge tanks. The insulin they now make can easily be extracted
