genetic engineering

Genetic engineering involves changing the DNA of one organism, by inserting genes from another.

This is normally the genome(all the DNA). It involves the use of enzymes and vectors(carriers).

The name of the vector we are now using is bacteria.

Studies can show reasons for certain behaviours.

Researchers can compare different behaviours between two opposing types.

This information can be used to see how their brain works.

It reduces the gene pool.

Can cause health problems e.g: breathing problems in dogs.

Ethical issues can occur- deliberate breeding of negative characteristics.

New diseases can occur- not much variation because the gene pool is closely related.

Desirable gene is cut from the chromosome using restriction enzymes.

Pieces of DNA are left with sticky ends where they were cut (sticky ends are matching DNA bases).

Plasmid is cut using the same restriction enzymes.

The gene is inserted onto the plasmid using ligase/enzyme to form a recombinant DNA.

This recombinant gene is inserted into a vector/ bacteria cell

Recombinant DNA is a plasmid + extra gene

Crops can be modified to be resistant to herbicides

                                 BUT

Genes getting into the environment can create super weeds and food chains can be adversely affected.

Natural selection is a process in which organisms are more likely to survive and reproduce than other embers of the same species.This can happen because they have certain genetic variations which come from two different sets of parental genes.

Less attractive organisms chooses another to mate with because of an attracting characteristic. One of the mates will be slightly smaller/grey in colour and choose a mate with: bigger structure, colourful feathers, singing better(birds), dancing and/or stronger male(fighting off another). All these lead to variations which make organisms more likely to survive and reproduce. This leads to new species evolving. variations=differences

Steps to follow:

1)Reproduction

2)Variation occurring due to mutation

3) Competition- survival of the fittest - one who can find effective ways to adapt by having those features as well

4) Overtime- new species

The giraffe population mated and produced many offspring. There is always a variation of different lengths in necks in giraffes due to mutations occurring. They all fed on the trees. Leaves on short trees became scarce and longer necks could feed only.

Shorter necks could not reach taller trees and died. Longer necks survived , reproduced and passed the genes onto their offspring. Offspring had longer necks and they mated; long necked giraffes increased in number and started a new species.

Bacteria would reproduce rapidly in a short time. There are stronger and weaker bacteria(variation).Weaker bacteria are destroyed by the anti-biotics. Mutations occur which makes some bacteria resistant to the anti-biotics. Those will survive longer and have a chance to reproduce quickly. This leaves the resistant ones behind which cannot be destroyed by the antibiotic. They spread and cause infection.

Scientists believe that species alive today evolved from species in the past.

Fossils provide good evidence for evolution and are the remains of organisms from millions of years ago which are found in rocks.

Fossils can form when parts of organisms have not decayed; if parts of the organism are slowly replaced by minerals during the decay process, fossils can form.

Fossils can be the preserved traces of organisms.Problem- many of the earliest forms of life were soft bodied organisms (no bones, no shell or skeleton).

Many of the fossils that did form have been destroyed by changes to rocks in the earth's crust; scientists cannot be certain how life on earth began.

A species is extinct when there are no remaining individuals of that species still alive.

Species can become extinct due to a catastrophic event, environmet changes, a new disease or a new predator.