1. Evolution!

2. What is Evolution?
Evolution- the genetic change of populations over time
Population- group of organisms of the SAME species that occupies certain area
Species- organisms that can interbreed and produce FERTILE offspring
Ex:
-whitetail rabbits -deer
-sparrows -squirrels

3. Liger (lion and tiger)-infertile

4. Cama (camel and llama)-infertile

5. How Do We Know Populations Evolve?
Population Sampling- technique uses part of population to represent whole population
Capture 100 random rabbits
These rabbits are a representation of all the rabbits in the area.
We can study many things within this group…

6. Genetics of the Population…
Gene Pool- all of the genes of every individual in population sample
Frequency- how often something occurs
Population genetics involves studying the frequency with which certain alleles occur in a population’s gene pool
In 50 years, will the  allele frequencies be the same?

7. Hardy-Weinberg
Hardy-Weinberg Equilibrium Principle – frequencies of the dominant and recessive alleles in a population change in time due to 5 things:
Mutations
Migration
Natural selection (survival of fittest)
Small population
Non-random mutation
If these things occur, then the frequencies change and a population evolves

8. History of Evolutionary Thought
Before 1850, most people believed…
Earth formed by supernatural events and never changed
Earth only a few thousand years old
Each species was made to fit its environment
Species never changed and did not go extinct

9. Early Scientists’ Ideas
Darwin deserves credit for the Theory of Evolution as we know it today
He was not the first to come up with the idea:
Carl Linnaeus proposed a new system of organization for plants and animals based on their similarities (noticed relationships)
Erasmus Darwin considered how organisms could evolve through mechanisms such as competition
Jean-Baptiste Lamarck presented evolution as occurring due to environmental change over long periods of time

10. Carl Linnaeus
Developed a classification system for the huge variety of living things he found
Wrote book Systema Naturae in 1735 to reveal his classification system
There are currently 1.9 million species that have been identified using his method
Linnaeus’s system of classification reflects evolutionary relationships

11. Jean Baptiste Lamarck
A French naturalist who proposed that populations of species evolve
His idea proposed:
Changes in an environment cause an organism’s behavior to change, leading to greater use or disuse of a structure or organ
The organism would pass on these acquired changes to its offspring, so a species would change in time
Idea called “Evolution by inheritance of acquired characteristics”
Wrong on several accounts

13. Charles Darwin At 22, was invited to sail on the “HMS Beagle”
Was going to school to be a minister-believed God created each species to match its habitat and they never changed
Thought Earth was about 6,000 years old and didn’t change, just like everyone else

14. Darwin’s Observations
One place of note that he visited was the Galapagos Islands
During journey, he made observations and recorded them in a journal
Darwin observed fossil and geologic evidence supporting an ancient Earth

15. Darwin’s Finches
When Darwin traveled to the Galapagos he took interest in the finches
He noticed the finch species on the islands were different, but all resembled one from S. America
Darwin thought some migrated and new species evolved

16. Darwin’s Finches This is what Darwin proposed:
Finches migrated from South America to the islands
Populations on different islands adapted to different environments and food sources they found
Those that could survive passed on their genes
Those that couldn’t survive perished

18. Darwin’s Finches
Over time different mutations accumulated in the different finch populations on the different islands
The populations diverged, or became more and more different from each other

19. Darwin’s Finches
The populations on the islands became so different they no longer mated if they met
Several new finch species evolved from a common ancestor from S. America
This is an example of macroevolution

21. Recent finch
research

22. Speciation Geographic Isolation!
Geographical isolation- members of a population are separated geographically
Major step that leads to speciation
Due to volcanoes, earthquakes, flooding, etc.
Can lead to divergence and then speciation
Geographic
Isolation!

23. Artificial Selection
Artificial selection- human intervention in animal or plant reproduction to ensure that certain desirable traits are passed on
Instead of NATURE selecting which traits are favorable, HUMANS selectively breed those animals with favorable traits
Ex. dogs or racehorses
Darwin bred pigeons to
explore this idea

24. Darwin’s Results In 1859, Darwin published The Origin of Species
His book stirred up controversy
Idea called “Evolution by natural selection”
Darwin Video

25. Darwin’s Book Explained Natural Selection
Natural selection- organisms best suited to their environment survive and reproduce
Darwin’s proposed mechanism of evolution
Survival depends on the particular environmental conditions a species finds itself in—nature!
If the environment changes, so do the populations that live there
Adaptation- using inherited genetic characteristics to increase chance of survival in new environment
Natural Selection and Salamanders

26. Natural Selection
Three conditions necessary for natural selection to occur:
Genetic variation: Individuals within a population must be genetically different
****Random mutations are the raw material for evolution to occur!!!!!!!
Overproduction of offspring: More organisms are born than can survive
Differential reproduction: Certain traits enable individuals to survive and have more offspring than others

27. Result of Natural Selection
Genes that help a population survive in their conditions stay in their gene pool, while “unfavorable” genes gradually decrease in frequency
This causes changes in the genetics of populations EVOLUTION!!!!!
As new mutations accumulate over a long time, the new populations no longer can mate with the original they started as. New species have formed!
Natural Selection –Crash Course

28. Whose idea for
evolution is this?
Evolution: How does is really work ?

29. Review
Most important concepts ?

30. Inherited Variation Artificial Selection
Every species has variation in the traits that it expresses.
These traits are inherited.
Mutations can occur.
Ex: Peppered Moth
Artificial Selection
When humans select for the traits that they consider the most important.
They will breed for these traits.
Ex: Cats, dogs, crops etc.

31. Ex: Peacock tail or displays of dominance
Struggle for Existence
Each member of a species competes against the other for food, living space and other life necessities
Creates: faster predators, camouflage, better protection adaptations (quills)
Survival of the fittest
How well an organism is suited for their environment.
It’s about survival and reproduction.
Adaptations that increase survival get passed on.
Adaptation can be anatomical/ structural or physiological process or behavior.
All in terms of fitness in the environment.
Descent with Modification
Natural selection over a long period of time.
Speciation.
Common ancestor that evolved.
Certain characteristics were modified over a long period of time until new species were formed.
Ex: California Salamanders and Finches on Galapagos Island
Evolution through Sexual Selection
Some characteristics or behaviours evolved purely as a means of finding a mate.
Ex: Peacock tail or displays of dominance

32. What We Know Now Evolution is a Scientific Theory
Not a hypothesis, or an educated guess, or a “theory” in layman’s terms
Unending amount of evidence to support it and NONE to reject it
Evolution is called “the unifying principle of Biology”
Isn't Evolution JUST a Theory?

33. Types of Evolution
Evolution - genetic change of a population of organisms over time descent with modification
Microevolution:
Small genetic changes of a population
Shorter amount of time
Bengal tiger simulation was microevolution

34. Types of Evolution
MACROevolution-When new species are formed over long periods of time
Due to tremendous amounts of accumulated genetic changes in a population
Speciation- formation of new species due to accumulated microevolution and mutations

35. How does macroevolution work?
dibosirdsaur
GEOGRAPHIC ISOLATION
dibosirdsaur dibosirdsaur
10 million years of accumulated mutations
diosirdsaur ibosirdsaur
10 million years of accumulated mutations
diosirdsaur iboirdsaur
dinoirdsaur boirdsaur
dinordsaur boirdsur
dinodsaur boirdsu
dinodsaurs boirds
DINOSAURS BIRDS

36. EVOLUTION by natural selection Microevolution MACROevolution Changes
in gene frequencies
in a population
Accumulated
microevolution and
mutations to form
whole new species
Examples:
Peppered moth
And Californian
Salamanders
Shorter times
Examples:
Darwin’s finches
and
Geographical
isolation
Longer times
Why is Evolution Controversial ?

37. Evidence for Evolution
Three types of evidence:
Fossils
Anatomical
Molecular

38. Fossil Evidence Fossils- any traces of dead organisms dinosaur bones
insects trapped in tree sap
leaf impressions
footprints

39. Fossil Evidence
Transitional species- species that have been found in the fossil record that are intermediates between two other species in the evolutionary process
Radiometric dating- a dating technique that measures amount of radioactive material in a rock or fossil
Relative dating- a dating technique that estimates the date of a fossil by relating it to the age of the layers of rock around it

40. Fossil Evidence To fossilize an organism must be buried by sediment
Relative
Dating
Radiometric
Dating
To fossilize an organism must be buried by sediment
In swamps, mud, tar pits, or the ocean bottom
Hard stuff fossilizes (bones, nails)
Radiometric and relative dating are used to find out how old the fossil is

42. Fossil Evidence Fossils show:
Life has been around for millions of years
Transitional species link older to newer species
Darwin proposed the idea of transitional species, though he had no evidence
Today we have evidence:
Archaeopteryx
Tiktaalik Fossil, etc.
Whales

43. Fossil Evidence-Archaeopteryx
WINGS
BEAK
Ted Talk- Dino Chicken

44. Fossil Evidence Whales--60 million years of evolution
Descended from 4-legged wolf-like animals that were also ancestors to cows and horses
Fossil evidence shows slow loss of legs
Pelvis still remains with no rear legs

45. Anatomical Evidence
Anatomical evidence- evidence for evolution which is based on similarities and differences between the physical structures of different species.
What can we tell about the relatedness of the three species below?

46. Anatomical Evidence
Homologous structures-Bone structure the same (homo) but not function
Bird wing, dolphin fin, and a human arm
The function these structures is not the same!
Shows that these species shared a common ancestor
Similar structures with different functions resulted from accumulated mutations and modifications

48. Homologous Structures

49. Anatomical Evidence
Analogous structures- Bone structure different but serve the same function
Function = flight
Butterfly wing, bat wing, fly wing
These structures, although they have the same function, are not built the same!
Show different species evolved structures with similar function through different evolutionary pathways
EVOLUTION IS NOT RANDOM!

50. Anatomical Evidence

52. Anatomical Evidence
Vestigial structures-structures that no longer serve a function
These structures are the remnants of an evolutionary past and show common anatomy with other species

53. Molecular Evidence
Molecular evidence- evidence concerning the comparison of DNA and protein molecules between species
Ultimate tools for scientists studying evolution
Same genetic basis for all organisms: A, C, T, and G shows we are all related

54. Molecular Evidence Mutations and sexual reproduction are a cause of
variation in a species’ DNA
DNAmRNAprotein
Transcription- copying the DNA code into mRNA
Translation- converting the code of mRNA into a long chain of amino acidsprotein
Differences in DNA are seen in differences in protein and therefore, traits

55. Molecular Evidence
Species with more similar DNA are more closely related on the evolutionary tree
Less time since they split to accumulate mutations (and, therefore, differences)
Common ancestor- any species in the past from which two or more related species has evolved
Evidence for Evolution
= speciation event = mutation

57. Doc Zone The Disappearing Male
What does this say about the next step in our evolution ?