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Redbrowed finch House finch How do these two species of Finch vary Why do they vary DONT TOUCH ANYTHING ON THE TABLES All you need is a pen or pencil WALT understand how adaptation can lead to evolution ID: 540460 Download Presentation
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Presentation on theme: "Variation"— Presentation transcript
Slide1
Variation
Red-browed finch
House finch
How do these two species of Finch vary?
Why do they vary?Slide2
DON’T TOUCH ANYTHING ON THE TABLES
All you need is a pen or pencilSlide3
WALT understand how adaptation can lead to evolution.Slide4
Variation
Red-browed finch
House finch
How are these species of Finch adapted?Slide5
Charles Darwin
Modern ideas of evolution started with Charles Darwin
.
In 1831 Darwin set out as a ship’s naturalist on HMS Beagle, it was a 5 year voyage to South America and the South Sea Islands.Slide6
Voyage of the Beagle
Darwin recorded observations of plants and animals that he saw on the voyage.In the Galapagos islands Darwin observed that each of the islands had similar types of finches, iguanas and tortoises, but that each was different to make the most of local conditions.Slide7
What are different types of beaks suited
to?
Your task is to plan an investigation to find out which birds’ beak would be best at helping a bird to survive on a diet of a particular seed.You have 7 minutes of discussion with your group, then 5-10 mins to write up what you’re going to do.
Time:
10 minutes
Expectation:Everyone to complete first 3 finches.Slide8
Writing up an investigation
AimApparatusMethodFair test
PredictionResults DiagramConclusionSlide9
The birds have been separated by a storm onto two different islands. There has been a drought and most food types have died out, so the food that is available on each island is now different.
ImagineSlide10Slide11
Finch DistributionSlide12
How does this model help us to understand why different species exist in different environments?Slide13
Darwin’s Theory
Darwin only observed one type of finch on the mainland- similar to the Galapagos Small Ground Finch.
He proposed that all finches evolved from the one species that lived on the mainland.Slide14
What factors would have to exist for a species to be able to change?
Genetic variation due to mutation.Competition; for food, mates, territory, to avoid predation.
‘Survival of the fittest’ the organism that is best adapted to its environment will survive.Reproduction- passing on the advantageous alleles to the offspring.Leading to change in the species over time- evolution.Slide15
https://
youtu.be/BcpB_986wykSlide16
In whichever way you’d like, explain the process of evolution.Slide17
What if . . .
The seeds on Espanola started to increase in size?
What would you expect to happen immediately to the population of Small Ground Finches?What would you expect to see happen to the population over the next 20 years?
What would happen if the size of the seeds decreased again in the future?Slide18
Exam question (5 marks)
Amauris
Hypolimnas
Both species can be eaten by most
birds.
Amauris has a foul taste which birds do not like, so birds have learned not to prey on it.Hypolimnas
does not have a foul taste but most birds do not prey on it. Describe, in terms of natural selection, how
Hypolimnas
may have developed its wing markings
Two different species of butterf
ly:Slide19
Mark Scheme:
Mutation caused changes in marks in Hypolimnas
.Competition; less predation of butterflies with these markings.These butterflies survived to reproduce; other butterflies were eaten.Advantageous allele/
gene was passed on to offspring.Over time population of Hypolimnas start to look more like Amauris
; evolutionRemember: make your answer specific to example given.