6.4 Isolation and the Evolution of New Species Flashcards Preview

GCSE Biology 2.6 Old and New Species > 6.4 Isolation and the Evolution of New Species > Flashcards

Flashcards in 6.4 Isolation and the Evolution of New Species Deck (11)
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What is geographical isolation?

Where landforms separate a species so they become isolated


Name 4 ways geographical isolation can separate species

•an island separates from the mainland
•a new river splits into 2 areas
•mountain ranges split into 2 areas
•old craters separate areas


Name 3 reasons for new species

•genetic variation/natural selection
•after mass extinction
•population isolation


How does population isolation work?

1. The species becomes isolated by geographical isolation
2. Natural selection causes the species to become evolved to that specific area as they may be exposed to different environmental conditions, food availability or predators.
3. Natural selection will happen in both areas but different characteristics will be beneficial in each area
4. Interbreeding between the old and new species is not possible because they are so varied


What do natural cycles linked to environmental change result in?

New species forming and old species dying out


What happens to populations in an isolated area?

Alleles are selected that increase the chance of survival in the new environment


What is speciation?

When two geographically isolated species can no longer interbreed as they have become so different


Explain speciation

1. Geographical isolation splits a population into 2
2. Each population has a wide range of alleles that control their characteristics, known as genetic variation
3. Natural selection occurs in both areas so adapt the animals to their habitats so their chances of survival are increased. The alleles that control the characteristic to help the animal survive are selected so the organisms with those alleles will survive and breed
4. If the environment, competitors, food supply and predators are different for each area they will evolve differently
5. Speciation has occurred when the organisms can no longer successfully inter breed


Shorthand for speciation using the correct terms?

1. Isolation
2. Genetic variation
3. Alleles selected
4. Interbreeding no longer possible
5. Speciation


Name an example of speciation

Darwins finches became isolated on different islands and evolved differently mainly due to different food supplies


How can new species arise from existing species?

A group becomes isolated from the rest