1. EVOLUTION

2. HISTORY OF LIFE
You can now classify living things into kingdoms, but some organisms aren’t living anymore. They are extinct, meaning there are no more of this organism living. This is part of the evidence that life on Earth is different now than it was before.

3. The word evolution can be used to describe any change over time (music, fashion).
In Biology, it describes how over generations, species (groups of living organisms) change and are influenced by survival in their environment.

4. The Origin of Life
Spontaneous Generation (abiogenesis) – nonliving matter can produce life
People thought mice could come from grain

5. The Origin of Life
Spontaneous Generation – nonliving matter can produce life
1668 – F. Redi disproved the idea that decaying meat produced maggots
Francesco Redi

6. * However, people still thought that microorganisms arose from some vital force.
1850s Louis Pasteur – disproved spontaneous generation of microorganisms

8. Theory of the origin of Life
1. Simple organic molecules must have formed
Scientists hypothesize that:
2. These molecules organized into complex organic molecules

9. Early atmosphere consisted of :
Water vapor, Carbon Dioxide, Nitrogen, Methane gas, and Ammonia, but
NO OXYGEN WAS PRESENT

10. 1930 Oparin hypothesized:
1. Life began in the ocean
2. Energy from the sun and lightning produced organic molecules from the atmospheric molecules
Oparin (1924)
3. Rain washed molecules into the ocean to form the primordial soup.

11. Miller & Urey tested Oparin’s hypothesis.
They simulated earth’s early atmosphere and found amino acids, sugars, and small organic molecules (which are all needed in living organisms)
Stanley Miller

13. Sidney Fox – By heating solutions of amino acids, Fox created complex protocells. (large ordered structures with membranes that grow and divide)

14. EVOLUTION OF CELLS
First True Cells – prokaryotes evolved from protocell.
They were anaerobic heterotrophs
But they used up their food so ……
Autotrophs like archaebacteria evolved.
* They made food by chemosynthesis

15. Photosynthetic prokaryotes evolved.
They produce oxygen.
Ozone layer produced. Protects life from UV rays.
4. Triggered evolution of aerobic cells & eukaryotes

16. 2.Anaerobic prokaryotes
Endosymbiont Theory – proposes that eukaryotes evolved through a symbiotic relationship between prokaryotes
2.Anaerobic prokaryotes
3. Chemosynthetic prokaryotes
1.Protocells
4. Photosynthetic prokaryotes
5. Eukaryotes

17. EVOLUTION
* Process where organisms change over time in response to the environment
A theory based on geological fossil evidence
A. Lamarck’s Theory
1. Traits developed by use or disuse
a. If you use the trait = larger and stronger
b. if you don’t use the trait = smaller and weaker

18. Lamarck & his theory
2. Inheritance of acquired characteristics. Ex: giraffe

19. EVIDENCE OF CHANGE How do we know that life has changed on Earth?
1) One way is to examine living organisms for similarities, as Charles Darwin did with the finches.
2) A second way is to examine the fossil record for similarities.
3) A third way is to examine the DNA sequences for similarities.

20. Physical observations (begun by Darwin)
1) EVIDENCE OF EVOLUTION
Physical observations (begun by Darwin)

21. CHARLES DARWIN
Charles Darwin was the naturalist on the ship HMS Beagle whose job was to collect living things on a tour of South America. One important stop was a collection of islands called the Galapagos.
He noticed the Galapagos animals were similar to the mainland animals but had some unique differences. His careful observations led him to theorize the environment of the island selected which plants and animals survived best.

22. DARWIN’S FINCHES
One example Darwin observed was many different types of birds called finches. They had some of the appearance in common, but some differences like beak shape. The finches’ beak seemed to help them survive based on what type of food was in each islands’ environment. They were different from the mainland birds.
Click on the picture of the finches to watch a video about Darwin’s finches.

23. In summary, Darwin’s theory was the Galapagos finches came from South America, but over the generations the groups changed to better survive in their new environment.
The evidence for this change was seen by examining physical characteristics such as beak shape or feather color.
This change in species over time is called EVOLUTION.

24. 2) EVIDENCE OF EVOLUTION
FOSSIL RECORD

25. The fossil record is evidence that organisms have changed
The fossil record is evidence that organisms have changed. A fossil is a trace of a dead organism. For example, you can compare the bones of a dinosaur to the bones of other reptiles and birds that are living today.

26. Examining many layers of rocks can show how groups of organisms can change over time. Keep in mind, not every living thing leaves a fossil, so sometimes there are gaps or unexplained blanks.
Click on the picture of the amber fossil and then “Launch interactive” to watch a slideshow about amber and what it can show about extinct organisms.

27. FINDING THE AGE OF FOSSIL
Relative dating- relies on position of rock layers
(oldest fossils on bottom)

28. INDEX FOSSILS
These fossils are:
-found in rock layers of only one age
-found in many parts of the earth
-occur in large numbers
-lived for only short period
EX: trilobites-lived mil yrs ago

29. Trilobites

30. Radiometric or Radioactive Dating
*Gives absolute age (actual age)
EX:Carbon 14(C14) (is radioactive)
Living have a constant ratio of C-12 (normal) and C-14
After death the C-14 decays into
nitrogen(N-14)
HALFLIFE ½ C-14 decays into N =5,700yrs

31. C-14 Decays
Organism
Dies
11,400 yrs
¼ C-14 left
5,700 yrs
½ C-14 left
17,100 yrs.
1/8 C-14 left
Carbon Dating Explained

32. In summary, fossils are evidence of organisms that are no longer living and can show change through many years.
The evidence for this change was seen by examining physical characteristics seen between the different levels of fossils.
This change in species over time is called EVOLUTION.

33. 2. Development of Resistance through Physiological Adaptations to:
1. Antibiotics (bacteria)
2. Pesticides (insects)
3. Herbicides (weeds)

34. Evidence From Living Things
Compare Organisms:
Homologous Structure – body parts with same basic build but may have a different use or look.
Ex: bat wing, whale flipper, human arm. *Similarities suggest a common ancestor

35. Homologous Structures

37. Homology
Two or more taxa Two or more taxa have the same underlying structure inherited from a common ancestor, modified for different functions.
Same 4 limb bones but used for different things. 37

38. Analogous Structures – Body parts with similar function but different structure Ex: butterfly wings and bird wings
* Not related by common ancestor

39. Ex: snakes have vestigial hip bones for leg attachment.
Vestigial Structures – body parts that seem to have no use – but probably did at one time.
Ex: snakes have vestigial hip bones for leg attachment.
Vestigial structures, such as pelvic bones in the baleen whale, are evidence of evolution because they show structural change over time.

41. 3) EVIDENCE OF EVOLUTION
DNA Comparison

42. Every living (or once living) organism has DNA in its cells
Every living (or once living) organism has DNA in its cells. This DNA tells the cells how to make proteins that give the living organism its traits (appearance). REMEMBER??? So, we can compare DNA or proteins to see how similar they are.

43. If we examine similar genes (like eye development), we can tell how closely related organisms are. For example, even though the proteins are all 100% similar, the shark’s DNA has more in common with the mouse than the fly.
DNA evidence is the most reliable because the DNA is either the same or different.
Click on the picture of the DNA and then click “Launch interactive” to watch a video about lice and DNA.

44. In summary, DNA similarities are evidence that organisms may have changed over time.
The evidence for this change was seen by comparing how similar the DNA is and grouping organisms into family trees.
This change in species over time is called EVOLUTION.

45. Summary
Evidence of Evolution

46. EVOLUTION Evolution is a change in groups over generations.
Evidence that organisms have changed can be found by looking at living organisms like Charles Darwin’s finches.
Evidence of change can be found by looking at fossils of ancient organisms and comparing them to organisms today.
Evidence of change can be found by comparing DNA sequences to see how similar they are.

47. NATURAL SELECTION
EVOLUTION

48. How Does Evolution Work?
On his journey with the HMS Beagle, Darwin studied many different living organisms. His research revealed that species changed over time.
Back at home in England, Darwin knew that dogs could be bred for certain traits the breeders wanted. Traits are features passed on from parents to offspring, like your eye color! This is called artificial selection and farmers still use it today!
What trait did breeders select for in bulldogs?

49. 2. Darwin realized for most organisms, nature was doing the selecting
2. Darwin realized for most organisms, nature was doing the selecting. The organisms that were best suited to an environment were the ones most likely to survive and pass on their traits. In a snowy environment like the Artic, white foxes are more successful because they are camouflaged. But in the woods, a brown fox is more successful. The process where organisms that are best suited for their environment survive and go on to produce more offspring is called natural selection.

50. Natural selection point 1:
Variation
3. Natural selection as a process has 4 key points. First is variation. The members of a species are all similar but they are not exactly alike. Traits are passed on to you through DNA from your parents. Some of the traits passed are on by accidental changes called mutations. If the mutation is helpful the trait will help the organism to survive, and it can be passed on to its offspring. Like the panda’s thumb. The extra big wrist bone helped the panda eat bamboo, and pandas with plenty of food were most likely to survive, so pandas with big wrist bones survived and passed on that trait. So part 1 of natural selection is that you can inherit variation.

51. OVERPRODUCTION
4. A second point about natural selection is that organisms overproduce, which means they produce more offspring than can survive. Fish can lay millions of little eggs. Many of the eggs never hatch, some might be eaten by a predator, and others might not get the nourishment they need to survive.

52. 5. COMPETITION
A third key point is that overproduction leads to competition.
Organisms have to have food, water, and shelter to survive.
Organisms also have to find mates in order to reproduce.
Since more organisms are born than there are resources available, organisms have to compete for the available resources.
Why would this fish be a “stronger competitor?”

53. 6. Natural selection
The fourth key point is that something in the environment “selects” which organisms are best fit. Sometimes it’s a predator, sometimes it’s mating preferences, but it is nature that is selecting who survives and has offspring. Sometimes in specific patterns like towards being “stronger” or “faster.” The important thing is that the population changes over time. Sometimes the organisms change so much they are different species. This is called speciation.
What environment would produce the pattern at the end “stabilizing selection?

54. NATURAL SELECTION IN ACTION
Click on one of the below links to watch an animation of natural selection in peppered moths. The selecting force here was both birds choosing which moths to eat and the industrial pollution staining the trees so that different moths were camouflaged.
What the evolution of the peppered moth on youtube & answer your questions on page 9 in notes.

55. 1. What is the variation in the moths. Light and dark colors 2
1. What is the variation in the moths? Light and dark colors 2.Why will not all the moths survive? Too many competing for food and eaten by predators 3. What exactly is helping some moths survive better? They match the color of the bark & are hidden from predators 4. After natural selection occurs, what will the population look like? They will be dark.

56. SUMMARY SLIDE
Natural Selection is the process where organisms best suited for their environment survive and then go on to produce more offspring.
Variation exists in populations.
This variation can be caused by random mutations and can be passed down from parents to offspring.
Overproduction - There are more organisms born than can live to survive.
Limited resources in the environment causes Competition for food, water, shelter, and mates. This results in Survival of the Fittest - those organisms with the most adaptive traits live longer and reproduce more.
This causes the population to change to be more like the most “fit” organisms – EVOLUTION by NATURAL SELECTION.