tidyribsevioWhat is the anagram? (don’t shout it out)

BiodiversityIn pairs – write down a definition for the word.

Learning outcomes

All of you should be able to:• Define the terms biodiversity, genetic

diversity, species diversity and habitat diversity.

• Define species and speciation

Most of you should be able to:• Outline the mechanism of natural selection.

What is biodiversity?

Biodiversity = Biological diversity“The variety of life on earth”

Up until now when talking about biodiversity we have focussed on species diversity but there are two other aspects…

Biodiversity includes

three aspects

Genetic diversity

Species diversity

Habitat diversity

What do you think these three different aspects of biodiversity mean?

Individually: write down what you think each one means.

HINT: you should already know species diversity.

Now have a look at what you have written and compare it with the following definitions.

Is there anything that you are missing?Add it to your definition.

Genetic diversityThe range of genetic material present in a gene pool or population of a species.

Species diversityThe variety of species within a given area, habitat or region. This includes the number of species and the number of individuals of each species

This variety alters from habitat to habitat. The rainforests at one end with great variation and the polar ice caps at the other with little variation.

Habitat diversityThe number of different habitats per unit area that a particular ecosystem or biome contains. If diversity increase here it will probably lead to an increase in the other two.

Wild mustard species have much more genetic diversity than the domestic varieties

SpeciationSpeciation is the process by which new species form.

What is a species?

Equus ferus

Equus africanusUrsus maritimus

Hysterocrates maximus

Hysterocrates gigas

Ursus arctos

A species is defined as:

A group of organisms that can interbreed and produce fertile

offspring.

+ =

Mules cannot reproduce themselves so although donkeys and horses can mate they are considered different species.

How does speciation occur?

• 1859 - Charles Darwin published On the Origin of Species

• Culmination of his life’s work

• Outlined theory of the evolution of species by natural selection

• Species change over time due to natural selection, creating new and different species

Darwin’s discovery

Darwin knew about artificial selection, and argued that a similar process must occur in nature.

Wild mustard& domesticcruciform vegetables

Wild canids

Domestic dogs

Artificial Selection • nature provides variation, humans select

variations that are useful. • Example - a farmer breeds only his best

livestock

This led him to the idea of natural selection.

http://true-wildlife.blogspot.mx/2011/02/giraffe.html

http://worldwildlife.org/species/polar-bear

http://gardenofeaden.blogspot.mx/2011/10/cheetah.html

http://science.discovery.com/tv-shows/greatest-discoveries/videos/100-greatest-discoveries-shorts-natural-selection.htm

Get down Darwin’s four key points…

Natural selection

Also called “survival of the fittest”

What do you understand by the term fitness in this context?

Let’s have a go at the worksheet…

Natural Selection and Species Fitness

• Overtime, natural selection results in changes in the inherited characteristics of a population.

• These changes increase a species fitness (survival rate)

What adaptations do these animals show that increase their fitness for their environment?

http://animal.discovery.com/mammals/camel/http://www.skjoldenllamas.net/en/index.php

http://animals.nationalgeographic.com/animals/mammals/brown-bear/http://worldwildlife.org/species/polar-bear

Let’s finish there

Put your notes away:

• Define biodiversity• Define species diversity, genetic diversity and

habitat diversity• Define speciation• Outline the mechanism of natural selection

Now take your partner’s and check it… add anything that they have missed.

• BiodiversityThe variety of life on earth – can include habitat diversity, species diversity and genetic diversity

• Species diversityVariety of species per unit area – number of species and relative abundance (number of individuals of each species)

• Habitat diversityThe range of different habitats in an ecosystem

• Genetic diversityThe range of genetic material present in a gene pool or species population

• SpeciationThis is the process by which new species are formed

• Outline the mechanism of natural selectionEach organism will be adapted slightly differently to their environment. Resources are limited and there will be competition for resources. These small differences mean that some organisms will be more successful than others and more likely to survive and reproduce, passing their genes on to the next generation. Survival of the fittest.