1. EVOLUTION

2. CHANGE Look at this picture which shows the process of evolution
Using only one word explain the meaning of evolution

3. And from a biological
point of view?
Let's work out a more specific definition …

4. Best Selection Species Struggle Fittest Offspring Heritable Adaptation
Enviroment
Heritable
Species
Adaptation
Change
Survival
Evolve
Population
Competition
Struggle

5. (processed at the level of the genes)
Evolution: process of change in the inherited traits of a population of organisms from one generation to the next
(processed at the level of the genes)

6. How does evolution occurr ?

7. Promotes diversity of characters in the offsprings
by providing genetic variation
SEXUAL
REPRODUCTION
Offers the opportunity to produce recombinant types
that can make the population better able to keep up
with changes in the environment.

8. OFFSPRING ARE GENETICALLY UNIQUE FROM:
Indipendent assortment (2 n possibilities)
Crossing over
Random fusion of gametes

9. They provide the genetic diversity
that makes natural selection possible.
MUTATIONS
the row material of
evolution
Phenotyipic change in the offspring
Somatic cell
Germ line cell

10. Organism with favorable traits are more likely to survive and
NATURAL
SELECTION
Organism with favorable traits are more likely to survive
and
to leave more offspring better suited for their enviroment

11. In this image appears Alfred Wallace and Charles Darwin,
both came up with the theory of evolution.
Look trough these web sides, work in pairs and make an interview each other with questions like these:
•Where and when they were born;
•Where and when they died;
•What they did;
•Their nationality;
•They were known because.…;
•The problems associated with their theory…. • •

12. Charles Darwin – the boy
Charles Darwin was born on 12th February 1809
in Shrewsbury, England.
He went to boarding school in Shrewsbury and
in 1825 went to Edinburgh University to study
medicine.
Whilst in Edinburgh Darwin investigated marine
invertebrates and started to develop a growing
interest in natural history.
In 1827, at the age of 18, Darwin realised he did
not like the study of medicine and could not bear
the sight of blood or suffering. He left Edinburgh
for Cambridge University with the idea of becoming
a clergyman.

13. Charles Darwin – the young man
Whilst at Cambridge Darwin met a number of people who were influential in shaping his career. His cousin William Darwin Fox, who was a keen collector of beetles. John Henslow, who studied and lectured on plants. Professor Adam Sedgewick, who taught him about geology during an expedition to Wales in In August 1831, Henslow wrote to Darwin inviting him to become a naturalist for Captain Fitzroy on the survey ship the Beagle.

14. Darwin and the Voyage of the Beagle
The mission of H.M.S. Beagle was to map the oceans and collect oceanographic and biological information around the world. The map indicates the ship's path, and the inset shows the Galapagos Islands, whose organisms were an important source for Darwin's ideas on natural selection.

15. An idea that would change the world
Charles Darwin and Natural Selection
An idea that would change the world
Charles Darwin developed his
theory of evolution by natural selection
using FOUR important OBSERVATIONS
which led him
to TWO DEDUCTIONS.

16. Up to 7 kittens
Female pig (Meishan)
Female rabbit
Up to 60 kitten

17. One of Darwin’s first observations was that
all living things are capable of producing
more offspring than are needed to replace
their parents.
Chick

18. Do they all survive to become adults?
1. All organisms produce more offspring than survive to adulthood

19. English economist Thomas Robert Malthus (1766 - 1834)
Both Darwin and Wallace were influenced by the ideas of the economist Thomas Malthus, who in 1798
published An Essay on the Principle of Population.
Malthus argued that because the rate of human population growth is greater than the rate of increase in food production, unchecked growth inevitably leads to famine
Darwin saw parallels throughout nature.

20. Herds of many animals live on the plains of Africa: wildebeest, zebra, gazelles etc.
Each year many of the females give birth to young, but the overall population sizes

21. 2. Populations remain more or less constant in numbers
Darwin’s second observation was that the numbers of many different species of animals and plants tend to stay fairly constant over long periods of time.
There are a number of factors which keep the population numbers stable, including competition for food, predation and disease
2. Populations remain more or less constant in numbers

22. Look at these giraffes
Do they belong to the same specie?
Are they identical?
Darwin’s third observation was that all living things vary slightly in colour, shape, size or behaviour.

23. 3. Members of the same species show variation in characteristics
Different colourings and skin patterns found in the giraffe.
3. Members of the same species show
variation in characteristics

24. Which is the differerence between these characteristics?

25. Darwin’s fourth observation was that many features are passed on from parent to offspring.
Some inherited characteristics are quite easy to see in humans:
Eye colour
Hair colour
Some are not so easy to see:
Blood group
Mendel
4. Some characteristics are inherited and so passed on to the next generation

26. French biologist Jean Baptiste Lamarck (1744–1829)
“The inheritance of acquired characteristics”
“Change through use and disuse”:
When environments changed, organisms had to change their behavior to survive.
If a giraffe stretched its neck for leaves, for example, a "nervous fluid" would flow into its neck and make it longer.
Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations.
Meanwhile organs that organisms stopped using would shrink.

27. DEDUCTIONS? CONCLUSIONS?
Observations
Observations:
1. All organisms produce more offspring than survive to adulthood
2. Populations remain more or less constant in numbers
3. Members of the same species show variation in characteristics
4. Some characteristics are inherited and so are passed on to the next generation
4. Some characteristics are inherited and so passed on to the next generation
DEDUCTIONS? CONCLUSIONS?

28. Describe what's happening in these pictures..............
Pigeon and sparrow
Describe what's happening in these pictures
Spider and fly
Polar bears

29. A. All organisms are involved in a struggle for survival.

30. Striped tigers and leopards spots: WHY?
It is an adaptation to the enviroment in which they live.
Camouflage themselves to ambush their prey too

31. Pygmy seahorse camouflaged against fan coral

32. to their environment than others.
B. Some individuals are better adapted
to their environment than others.

33. Silverback mountain gorilla
Survival of the fittest
The individuals that are best adapted to their environment are most likely to survive and have the chance to reproduce, therefore passing on their useful adaptations to the next generation. Those individuals that are the least well adapted do not survive long enough to breed.
Silverback mountain gorilla
Male African lion
These ideas formed the basis of Darwin’s theory of evolution by natural selection.

34. Alfred Russel Wallace (1823 –1913)
English naturalist, explorer, geographer, anthropologist, and biologist
Alfred Russel Wallace (1823 –1913)
Alfred Russel Wallace,
was studying the biota of the Malay Archipelago.
Wallace asked Darwin to evaluate the manuscript, in which Wallace proposed a theory of natural selection almost identical to Darwin's.
At first Darwin was dismayed, believing that Wallace had preempted his idea.

35. 24 Novembre 1859
The origin of species

36. A population showing variation in colour.
Continuous or discontinuous?

37. There is lots of food so your population survives and reproduces. Add 5.

38. The bright yellow of some of your offspring attracts predators
The bright yellow of some of your offspring attracts predators. All but two of them get eaten.

39. There’s lots of food and hiding places for the green and
blue, but the red ones can’t hide and get eaten.

41. Plenty of food and its spring so another 10 offspring are born, they are a variety of colours.

42. Plenty of food and its spring so another 10 offspring are born, they are a variety of colours.

43. It’s winter and 5 of your population die

45. Its mating time again, blue and green mate and produce 5 green and 2 blue offspring. A mutation also produces 2 red offspring

46. Its mating time again, blue and green mate and produce 5 green and 2 blue offspring. A mutation also produces 2 red offspring

47. There is lots of food, and all reproduce 2 offspring, but the white are better at finding water and hiding from predators so they produce 5 offspring

48. There is lots of food, and all reproduce 2 offspring, but the white are better at finding water and hiding from predators so they produce 5 offspring

49. The bright red colour attracts mosquitoes carrying a deadly disease
The bright red colour attracts mosquitoes carrying a deadly disease. They all die.

50. The bright red colour attracts mosquitoes carrying a deadly disease
The bright red colour attracts mosquitoes carrying a deadly disease. They all die.

51. It is a particularly hot summer, blue and green are poor temperature regulators; white and yellow, which reflect heat, are more likely to survive.

52. It is a particularly hot summer, blue and green are poor temperature regulators; white and yellow, which reflect heat, are more likely to survive.

53. When food is plentiful again the remainder mate and produce 5 offspring some white and some yellow.

54. When food is plentiful again the remainder mate and produce 5 offspring some white and some yellow.

55. A scientist finds this population and reports that this species occurs in two colours. He says they have adapted to their habitat. What does he mean?
What is the population?
Has it changed?