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2. Immagini e concetti della biologia Sylvia S. Mader
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

3. A8 - Principles of evolution
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

4. Darwin’s journey
In 1831 Charles Darwin made a journey around the world.
He observed that species change from place to place and through time.
Charles Darwin ( )
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

5. Darwin’s journey
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

6. Darwin’s observations
Rheas living in South America had the same adaptations to desert as african ostriches.
Darwin's Rhea
Marine fossils in the rocks of the mountains.
Earth’s strata contain fossils
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

7. Darwin’s observations
Similar organisms living in the Patagonia desert and in tropical forests showed different characteristics.
Patagonia desert
Tropical rain forest
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

8. Darwin’s observations
Galapagos iguanas had claws and muzzle adapted to the environment.
Marine Iguana
New species of finches on the Galàpagos had different beaks in relation to their feeding habits.
Woodpecker finch
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

9. Darwin’s knowledges supporting evolution
Charles Lyell (geologist)
Earth is old enough for evolution to have resulted in the species seen today.
Georges Cuvier (paleontologist)
Catastrophes caused evolution to occur.
Jean-Baptiste de Lamarck (zoologist)
Inheritance of acquired traits is a mechanism of evolution.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

10. Artificial selection mimics natural selection
wild mustard
Kohlrabi
Brussels sprout
Chinese cabbage
In agriculture humans select and maintain specific traits in certain populations.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

11. The natural selection
Members of a population have inheritable variations
Stronger individuals are more likely to reproduce
A population is able to produce more offsprings than the environment can support
There is always a struggle for survival
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

12. The natural selection
Darwin observed natural selection in Galàpagos finches.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

13. Studying the natural selection today
Scientist are observing variations in the beak of Medium Ground Finch (Geospiza fortis) in relation with climate changes at Galàpagos islands.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

14. Evolution
“A series of changes in a population over time, due to an accumulation of inherited differences”.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

15. Fossils provide records for the past.
Evidences for evolution
Fossils provide records for the past.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

16. Evidences for evolution
The fossil records indicate that life has progressed from the simplest organisms to more complex ones.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

17. Evidences for evolution
Some fossils (as Archaeopteryx lithographica) have intermediate characteristics between two different groups (i.e. birds and reptiles).
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

18. Evidences for evolution
COMPARATIVE ANATOMY
Homologous structures are anatomically similar among certain organisms and suggest that organisms have a common descendent.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

19. Evidences for evolution
COMPARATIVE ANATOMY
Some organisms have vestigial structures, memories of functional structures in ancestors.
Vestigial structure
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

20. Evidences for evolution
BIOGEOGRAPHY
Some plants and animals evolved in particular locations.
Therefore similar environments, widely separated, contain different organisms with similar adaptations.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012

21. Evidences for evolution
Molecular evidences
The degree of similarity of DNA (or amino acid) base sequences shows a pattern of relations between organisms.
Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012