•What is the biological concept of a species? What are the problems with this definition? How is the phylogenetic concept of a species different?

•How does the phylogenetic approach to classification differ from the more traditional Linnaean approach?

•What is meant by: Haplotypes%divergenceClades

Phylogenetic classification works in group called Monophyletic groups . These consist of an ancestral organism and its descendent species

Linnaean classification uses Paraphyletic groups which contains the most recent common ancestor but does not contain all the descendants of that ancestor. (eg. Reptiles)

Speciation

•The formation of a new species from a pre-existing one•Takes a very long time.....

•A Island with a population of small, insect eating birds

•A volcano erupts on the island and separates it in two

•On the island with the volcano there are more tiny rocks

•This means that on that island there is selection pressure for birds with longer thinner beaks that can reach in amongst these rocks. This pressure does not exist on the other island.

•The different selection pressures on each island (along with genetic drift) lead to differences in the genetics of the two populations

•If the populations are kept apart for long enough the differences will become big enough that if the birds can no longer interbreed and become a different species.

•This is allopatric speciation

•A Island with a population of small, insect eating birds

•A volcano erupts on the island and separates it in two

•On the island with the volcano there are more tiny rocks

•This means that on that island there is selection pressure for birds with longer thinner beaks that can reach in amongst these rocks. This pressure does not exist on the other island.

•The different selection pressures on each island lead to differences in the genetics of the two populations

•If the populations are kept apart for long enough the differences will become big enough that if the birds can no longer interbreed and become a different species.

•This is allopatric speciation

Sympatric Speciation

In sympatric speciation, species diverge while inhabiting the same place.Eg – a mutation causes a group of birds within a species to not recognise a mating dance. These birds will only reproduce with each other

Temporal Speciation

In temporal speciation seasonal behaviour changesEg a mutation makes a plant flower at a different time from the rest of its species. Flowers with this mutation will reproduce with each other but not with the rest of the population

Sympatric Speciation

In sympatric speciation, species diverge while inhabiting the same place.Eg – a mutation causes a group of birds within a species to not recognise a mating dance. These birds will only reproduce with each other

Temporal Speciation

In temporal speciation seasonal behaviour changesEg a mutation makes a plant flower at a different time from the rest of its species. Flowers with this mutation will reproduce with each other but not with the rest of the population

Natural selection Artificial selection

Agent of selection

Effect on allele frequencies

Effect on evolution

Speed

What are the similarities and differences between artificial selection and natural selection?

Explain how genetic variation is essential for the processes of natural and artificial selection.

What characteristics

have been selectively bread

into these organisms?

How have humans used selective breeding to produce modern dairy cattle?

How can a farmer produce far more offspring from the best cattle than would be possible naturally?

http://www.youtube.com/watch?v=rW54_vM9SF0&feature=fvw

http://news.bbc.co.uk/1/hi/uk/7569064.stm

Problems with selective breeding

Domestic wheat (Triticum aestivum)

A hybrid containing 3 distinct genomes

•AUAU from the wild wheat species T. urartu•BB from Wild Emmer wheat T turgidum•DD from wild goat grass

The plants have also undergone polyploidy, which means that their nuclei contain more than one diploid set of chromosomes

There are various different strains of wheat selected for different characteristics

Selective breeding of wheat continues (coordinated by the Camden and Chorleywood Food Research Association)