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.
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