Speciation

Speciation

The formation of new species. A species is defined as a group of similar organisms that can reproduce to produce fertile offspring. Speciation happens when the populations of the same species are isolated in some way and evolve to become so different that they can't breed with one another to produce fertile offspring. 

E.g. finches on Galapagos islands beak size.

The evolution of antibiotic resistance

Antibiotics kill or inhibit the growth of bacteria. 

MRSA is a strain resistant to methicillin.

Evolution of antibiotic resistance can be explained by natural selection:

• There is a variation in a population of bacteria. Genetic mutations make some bacteria naturally resistant to an antibiotic. 
• If the population is exposed to that antibiotic, only the individuals with resistance will survive to reproduce. 
• The alleles which cause the resistance will be passed on and…