1. Bellringer Did you pick the same “winner”? Explain why or why not.
Bellringer
Peppered moth population shows two variations:
Predator = birds
QUESTIONS!
Which moth would survive in this environment?
What about this one?
Did you pick the same “winner”? Explain why or why not.

2. You just invoked the idea of natural selection…
Survival of the “fittest”
What does it mean to be “fit”
What does it mean to be “Selected for”?
“who” or “what” is doing the selecting?
Natural selection results in changes in the inherited characteristics of a population.
Well-adapted for your environment
Able to survive and reproduce
The environment (weather, camouflage, predators)
Over time, a certain color moth is selected for…they reproduce…over time the population of moths includes more moths of that color!

3. You also just demonstrated evolution
Evolution = CHANGE in a POPULATION’S inherited characteristics OVER TIME.
What kind of change?
How much time?
Important to note…
The theory of evolution does not try to explain where life came from  origins

4. The Theory of Evolution

5. Change in a population over time
What is Evolution?
Change in a population over time
First evidence from the fossil record
Can an individual evolve new traits? NO! If I am a giraffe born with a short neck, I have a short neck! I can’t “evolve” a longer neck! But I have a decreased chance of survival…

6. Charles Darwin ( )
1831 – sailed to South America and the South Pacific on the HMS Beagle
5 year voyage
Collected and studied specimens at every port
Saw high DIVERSITY!
Became interested in relationships among species
Foundation for his theory of evolution by natural selection
Got the idea that species can CHANGE!
1859 – published first book about evolution - On the Origin of Species by Natural Selection

8. What did Darwin’s Travels reveal
The diversity of living species was far greater than anyone had previously known!!
These observations led him to develop the theory of evolution!!

9. Galapagos Islands Finch Tortoise
Beaks adapted for feeding on different things
Found nowhere else…different species from those on S. American mainland
Tortoise
Different body size and shape
Found nowhere else
Saw many organisms with similarities and differences…are they related?
Darwin got the idea that species can change over time!

13. Scientists that influenced Darwin
Hutton and Lyell – geologists
If Earth can change, life may also
Jean-Baptiste Lamarck
First to see that living things change over time and they are adapted to their environment
Said that by use/disuse, organisms acquired or lost traits and then could pass them to offspring

14. Lamark Theory of acquired characteristics
Lamark said organisms acquired traits by using their bodies in new ways
These new characteristics were passed to offspring
Lamark was totally wrong!

15. Really? This giraffe stretches his neck and then passes on this new trait to offspring? No!
Can you dye your hair pink and then pass on the pink hair trait to your kids? No! It’s not in your genes!

16. Malthus
Reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone

17. Artificial Selection There is variation among organisms of a species.
Humans select those variations that are useful.

18. Artificial Selection
nature provides variation, humans select variations that are useful.
Example - a farmer breeds only his best livestock

19. Another example of artificial selection

20. Natural Selection Natural selection
How change in populations occurs
Traits vary in populations, and sometimes the variations are inherited… individual organisms differ!
Species create lots of offspring, but they do not overrun the Earth! More offspring produced than can survive and not all reproduce
Individuals struggle to survive
Competition for resources, predators, etc.
Each organims has different advantages or disadvantages
Those individuals with the most beneficial adaptations survive to reproduce and pass on their genes!!!

21. Natural Selection
Organisms with certain variations survive, reproduce, and pass their variations to the next generation
Organisms without these variations are less likely to survive and reproduce
So, each generation is made mostly of offspring with the variations that allowed survival
“Survival of the fittest”

23. Over time, natural selection results in changes in the inherited characteristics of a population. These changes increase a species’ fitness in its environment.

28. Click here to watch the video clip
Click here to watch the video clip! – click how does evolution really work?
Flip to the back page and fill out the bottom after viewing! Pause if you need!

29. Summary of Darwin’s Theory
Organisms differ; GENETIC VARIATION
2. Organisms produce more offspring than survive; OVERPRODUCTION OF OFSPRING
3. Organisms compete for resources; STRUGGLE FOR EXISTENCE
4. Organisms with advantages survive to pass those advantages to their children; DIFFERENTIAL SURVIVAL AND REPRODUCTION

30. Where do these
variations come from?
MUTATIONS!

31. Genetic Change in a population over time
What is Evolution?
Genetic Change in a population over time

32. Population Genetics Individuals do NOT evolve, populations do!
Natural selection acts on a range of phenotypes in a population
Evolution occurs as a population’s genes change over time
Gene pool = all the genes (alleles) of a population
Allelic frequency = % of any one allele
Think about “Breeding Bunnies”

33. Evolution does not work this way.
                                                                                                                                                      
   
Evolution does not work this way.

34. Evolution happens as
genes and frequencies
change over time!

35. Types of Selection (will cause change in allelic frequencies in gene pool!)
Stabilizing Selection = favors the average individuals; extremes die off ; reduces variation
Ex: Plant height, spider size

37. Directional Selection = favors one extreme variation
Ex: Giraffe neck, woodpecker beak

39. Disruptive Selection = favors both extremes; average dies off, eliminates intermediate phenotype
Ex: limpet shell

42. Sexual Selection
(whales)
Changes seen in males and females due to male competition and female selectivity – leading to increased fitness

43. Evidence for Evolution
Adaptations
Fossils
Anatomy
Embryology
Biochemistry

44. Adaptations (any inherited characteristic that increases chances of survival)
Structural
Ex: Porcupine’s sharp quills
Mimicry
Look like another species
Ex: butterfly
Camouflage
Blend with surroundings
Ex: peppered moth
Physiological
Change in metabolic processes
Ex: the way a plant does photosynthesis
Adaptations may also be behavioral. Ex: mating calls, bird migration, etc.

50. Fossils
Fossils – the remains of ancient life; found in layers of rock formed at different times
Compare older and newer fossils to see changes (transitional fossils)
Fossil record gives evidence but is incomplete
Can see sequences of evolution

53. Anatomy
Homologous structures = structure with different mature form, but developed from same embryonic tissue
Different function but same structure – common ancestor
See figure link
Notice similarities in body parts of animals with backbones
Limbs of reptiles, birds, and mammals vary in form and function, but they are all constructed from the same basic bones
Limbs adapted in ways to enable the organism to survive in different environments
Different function but same structure – evidence of a common ancestor

55. Homologous Body Structures

56. Anatomy
Analogous structures - similar function but different structure
Do not show close common ancestor
Wings of bird and butterfly

57. Anatomy
Vestigial structure = no function in present-day organism, but useful to ancestor
Eyes of blind mole rat
Legs of a skink

58. Embryology
Embryo = earliest stage of growth and development of plants and animals
Embryos of animals with backbones are very similar
Link

62. Biochemistry Compare DNA or RNA or proteins
More similarities = more closely related = common ancestor
Ex: Are humans more closely related to a chimpanzee or a banana

63. Video Clips