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Starter Activity: On a show me board sketch a short story board to describe natural selection using...

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Speciation Learning Intention: Natural selection brings about speciation. Different factors can separate species and cause new species to evolve. Success Criteria: Explain what speciation is and what causes it to happen.
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Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.
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Page 1: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Starter Activity:

On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Page 2: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Speciation

Learning Intention: Natural selection brings about speciation.Different factors can separate species and cause new species to evolve.

Success Criteria: Explain what speciation is and what causes it to happen.

Page 3: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

What does the word speciesspecies mean?

Page 4: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

SpeciesA species is a group of organisms that can reproduce to produce fertile offspring.

Twig on Glow: Species (glossary)

Page 5: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

The Tree of Life

http://www.open.edu/openlearn/nature-environment/natural-history/tree-life

Page 6: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

What is speciation?

Twig on Glow: Origin of Species

Watch the video clip and note down any key words on your show me board.

Page 7: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

What is speciation?

Speciation is the formation of new species and natural selection is the mechanism that causes it to happen. This is the basis of the theory of evolution.

Page 8: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Factors involved in speciation

• Speciation is the formation of a new species from existing species.

• This depends on random mutations causing changes in genotype (genes) and phenotype (physical appearance) of some individuals.

• The change allows these organisms to exploit the environment they are in, helping them to survive and pass on their genes to the next generation.

Page 9: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

For speciation to occur three factors need to be involved:

1. Isolating mechanisms (to create sub-groups)

2. Random mutations (favourable)3. Natural selection

Factors involved in speciation

Page 10: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Large population of one species

Sub-population A Sub-population BMutation occurs

Isolation by a barrierbarrier

Species A Species B

mutant mutant

Natural Selection

Two species evolve

BarrierBarrier removed. Species A cannot breed with Species B. Speciation has

occurred.

Page 11: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Isolating mechanisms1. Geographical

Can you think of any geographical barriers that might prevent species

from exchanging genes?

Page 12: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Isolating mechanisms1. Geographical

mountains rivers

Oceans and seas

deserts

Page 13: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Isolating mechanisms 2. Ecological

Can you think of any ecological barriers that might prevent species

from exchanging genes?

Page 14: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Isolating mechanisms 2. Ecological

temperaturepH

humidity

Page 15: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Isolating mechanisms 3. Reproductive

Can you think of any reproductive barriers that might prevent species

from exchanging genes?

Page 16: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Isolating mechanisms

• Organisms like to reproduce at different times of year.

• Lack of attraction•Sex organs are the wrong size•Pollinating mechanisms fail

3. Reproductive

Page 17: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Speciation

What is speciation and what causes it?

Page 18: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Speciation Summary•SpeciationSpeciation occurs after part of a population becomes isolatedisolated.

•MutationsMutations occur in each sub-population.

•Natural selectionNatural selection selects different mutations in each group, due to different selection pressuresselection pressures.

•Each sub-population evolvesevolves until they become so genetically different they are two different species.

Key WordsKey WordsDiscuss the meaning of each underlined word with your

partner.

Page 19: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Speciation

Learning Intention: Natural selection brings about speciation.Different factors can separate species and cause new species to evolve.

Success Criteria: Explain what speciation is and what causes it to happen.

Page 20: Starter Activity: On a show me board sketch a short story board to describe natural selection using one of the examples you have learnt about so far.

Scottish SpeciationResearch and presentation task…Research and presentation task…

Scottish examples of isolation leading to speciation:Arran Whitebeam St. Kilda Wren Arctic Char

Choose one of the examples above and find out how isolation has caused it to evolve as a new species. You may present your work any way you like but you must work towards the following success criteria:You must include… Where the organism is found and information about it’s habitat.You should include… How the organism is adapted to where it lives.You could include… Explanation about how speciation has caused this new species to evolve: What are it’s ancestors? Is it linked to another species? Why is it classed as a new species? Any other interesting facts?


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