1. The Evolution of Living Things
Chapter 8
The Evolution of Living Things

2. Sec 1: Change Over Time

4. Red-Eyed Tree Frog
Smoky Jungle Frog
Strawberry Dart-Poison Frog

5. Differences Among Organisms
Adaptation - a hereditary characteristic that helps an organism survive and reproduce in its environment
Adaptations can modify structures involved in:
Finding food
Protection
Moving from one place to another

6. Living things that share the same characteristics and adaptations may be members of the same species
Species - a group of organisms that can mate with one another to produce fertile off spring
i.e. All red-eyed tree frogs are members of the same species and can mate with one another

8. Do Species Change Over Time
The Earth is estimated to be about 4.6 billion years old
As the planet has change over time, so have the living things on it.
Since life first appeared on Earth many species have died out and have been replaced by newer species
These changes are preserved as fossil evidence.
Scientists believe that newer species have descended from older ones
Evolution - the process by which populations accumulate inherited changes over time

10. Evidence of Evolution: The Fossil Record
Evidence that living things evolve comes from many different sources
Sources include fossils as well as comparisons among different organisms
Fossils - the solidified remains or imprints of once-living organisms found in layers of within the Earth
Fossils are usually formed when dead organisms are covered by a layer of sediment
CAN YOU GIVE ME AN EXAMPLE OF HOW THIS COULD OCCUR?

11. Reading the Fossil Record
Fossil Record - a historical sequence of life provided by fossils
Supplies evidence about the order in which evolutionary changes have occurred
Fossils found in the upper layers of the Earth’s crust tend to resemble present day organisms
The deeper the fossils are found, the less they look like present-day organisms
These fossils can be from organisms that are now extinct

12. CHAPTER 8 Quiz 1a
1) ________ is a hereditary characteristic that helps an organism survive and reproduce
2) ________ is a group of organisms that can mate and produce fertile offspring
3) ________ is the process by which populations accumulate inherited changes over time.
4) ________ are the solidified remains of once living organisms
B) ________ structure are the remains of once useful structures

13. Gaps in the Fossil Record
Not every organism that has lived becomes a fossil
Why??????????
Because the conditions to make fossils have to be perfect
No oxygen, buried in fine sediment, and organisms with hard body parts fossilize easier
Because of this there are gaps in the fossil record

14. Evolution of the Whale
Scientists believe that whales evolved from land dwelling mammals.
Mesonychid - lived 55
million years ago.
Ambulocetus – lived 50 million years ago and near coastal
waters. Used legs and tail
swim.

15. Rodhocetus – lived 46 million years ago and started to more resemble modern whales, but it still had hind limbs and feet. Used only its tail when swimming
`Prozeuglondon – lived 40 million years ago and was well adapted to sea life. Still had small legs, but lived only in the water

16. Comparing Skeletal Structures
Evolutionary scientists believe that the similarity of the bones in the front limbs of different organisms suggest that different organisms came from a common ancestor

17. Comparing DNA All living organisms from bacteria to humans have DNA
Organisms that appear to be more similar (chimps and gorillas) have more similar DNA than organisms that do not appear as similar (Chimps and birds)
All DNA in every organism contains the same four bases (guanine, cytosine, adenine, Thymine)

18. Comparing Embryonic Structures

19. In early development human embryos and the embryos of all other vertebrates appear to similar.
Scientist suggest that this is because we all came from a common ancestor

20. Chapter 8 Quiz 1b
1) __________ are the remains of once useful structures
2) T/F Mesonychid lived 55 million years ago and lived on land and in the water
3) T/F Humans, cats, and bats have similar bone structure in their front limbs
4) T/F All vertebrates have different looking embryos
B) __________is the name of the ship that Darwin sailed on

21. Section 2: How Does Evolution Happen?

22. The early 1800’s was a time of great scientific discovery
Scientists realized that the Earth was much older than they realized
Scientists began to discover fossilized remains of unusual organisms
Many scientists began to believe that evolution occurs, but no one had been able to explain how it occurred until………….

23. Charles Darwin

24. Charles Darwin
In 1831, 21 year old Charles Darwin just graduated college
Like many college graduates Darwin did not know what he wanted to do with his life.
His father wanted him to become a doctor
He talked his father into allowing him to sign on for a 5 year voyage around the world on the HMS Beagle
The observations made on this voyage became the foundation for his Theory of Evolution by Natural Selection

26. Darwin’s Excellent Adventure
As the Beagle traveled around the world Darwin collected thousands of plant and animal specimens and kept detailed notes of his observations
During the journey the HMS beagle visited the Galapagos Island

28. Darwin’s Finches
Darwin observed that the animals and plants on the Galapagos Islands were very similar, yet not identical, to those on the South American mainland
- The finches that Darwin observed where not only different from the mainland finches, but also from each other.
i.e. They differed by the shape of their beaks and the type of food they ate

29. Darwin Learns from Farmers and Animal and Plant Breeders
During Darwin’s time farmers were already choosing desirable traits and breeding these organisms together
This is called selective breeding
i.e. selective breeding in dogs has led to over 150 different breeds
Darwin was impressed that farmers could control traits and make such dramatic changes in animals and plants in just a few generations

30. Darwin Learned from Geologists
Darwin read Principles of Geology by Charles Lyell, and learned that the Earth is much older than anyone realized and was formed by natural process that took a long period of time
This was important because Darwin thought that populations of organisms changed slowly

31. Darwin Learned from the Work of Thomas Malthus
Malthus believed that humans had the potential to reproduce beyond the capacity of their food supply
This led Darwin to realize that other animal species where also capable of doing this
Because of starvation, disease, and predators only a limited number of offspring survive to reproduce

33. Chapter 8 – Quiz 2 1) Darwin was on the HMS Beagle for _______ years
2) When he studied the Galapagos finches he was most interested in their different ________
3) ___________ is when farmers breed two animals with ideal traits
4) Charles ________ was the Geologist that believed that the Earth was older than people though
5) T/F Malthus believed that humans could over populate their food
B) _________ is the period of time between the birth of one generation and the birth next generation

34. Natural Selection
In 1858, about 20 years after Darwin returned, he received a letter from naturalist Alfred Wallace.
Wallace had independently came to the same evolutionary principle
This prompted Darwin to publish his book, On the Origin of Species by Natural Selection
Darwin theorized that evolution occurred through a process he called Natural Selection
Natural selection occurs in four steps:
1) Overproduction
2) Genetic Variation
3) Struggle to Survive
4) Successful reproduction

35. Natural Selection
1) Overproduction – a species can produce more offspring than will survive to maturity
2) Genetic Variation – when individuals in a population are different than one another. Some traits are more suited to an environment and help the organism survive and reproduce
3) Struggle to Survive – Only some individuals in a population survive because of food, shelter, and predators.
4) Successful Reproduction – Individuals that are best suited for their environment are more likely to reproduce

36. Section 3: Natural Selection in Action
Insecticide Resistance
Insects can quickly develop resistance to insecticides because they have short generation times
Generation Time – the period of time between the birth of one generation and the birth of the next generation
Adaptation to Pollution
Organisms have adapted to changes (pollution) in their environment overtime.
In industrialized areas, European pepper moths have gotten darker over time.
This allows them to blend in with their backgrounds, making them harder to see

37. Formation of New Species
Speciation – when two populations become so different over time that they can no longer interbreed.
The three possibilities are:
1) Separation – when a portion of a population becomes isolated (i.e. newly formed canyon, mountain range, etc.)
2) Adaptation – separated groups are force to adapt to their environments or die
3) Division – Over many hundreds, thousands, or millions of generations, two groups many become so different that they can no longer interbreed

39. Chapter 8 – Quiz 3
1) _________ is the period of time between the birth of one generation and the birth of the next.
2) What cause the moths in England to become mostly dark?
3) _________ is when a population is separated and become so different that they can no longer interbreed
4) List the three steps to speciation. (Don’t make me SAD)
B) List the four steps to Natural Selection