Evolution: (Developing A Theory To Explain Change)

Question 1

Ancient theories (1):

Answer 1

•theory: statement that makes successful predictions about a broad range of observations.
•for centuries people have asked how life developed on Earth.
•many observations, hypothesis, and collected data support the theory of evolution by natural selection.
•widely accepted explanation of how life has changed.

Question 2

Ancient theories (2):

Answer 2

•Aristotle and Pluto both believed all species of organisms had been created independently of one another and had remained unchanged ever since.
•believed to be true for over 2000 years.

Question 3

1. Buffon’s histoire naturelle:

Answer 3

•French naturalist to first propose that life was changing due to similarities he noticed between apes and humans.
•speculated that they had a similar ancestor.

Question 4

2. Cuvier’s fossils:

Answer 4

•French palaeontologist that studied fossils in strata (layers of rock).
•found evidences that new species appeared and others disappeared over the passage of time.
•evidence for extinction.
•believed that the Earth experienced many destructive natural events, such as floods and volcanic eruptions, in the past. These events, which he called revolutions were violent enough to have killed numerous species each time they occurred.

Question 5

Ancient theory (3):

Answer 5

•the following scientists challenged this idea:
1. Buffon.
2. Cuviers.
3. Lyell.
4. Lamarck.
5. Darwin.

Question 6

3. Lyell’s principals of geology:

Answer 6

•Scottish geologist believed that changes in organisms occurred slowly and over long periods of time, eventually leading to the creation of a NEW species.
•rejected the idea of revolutions.
•inspired Charles Darwin and many others.

Question 7

4. Lamarck: the inheritance of acquired characteristics:

Answer 7

•believe that species increased in complexity over time, until they reached perfection.
•believed that organisms could acquire characteristics and pass onto children (example: develop large muscles and therefore offspring will have large muscles).
•even Charles Darwin believed this to be true.
•not until the 1800s, with the understanding of genes and hereditary did Lamarck’s ideas become refuted.

Question 8

5. Charles Darwin’s theory of natural selection (1):

Answer 8

•round the world voyage in the HMS Beagle, 1831.
•studied finches on the Galapagos Islands.
•saw various beak adaptations used for different feeding techniques/diets on different islands (crushing seeds, eating fruits, feeding on insects, ect).

Question 9

5. Charles Darwin’s theory of evolution by natural selection (2):

Answer 9

•those finches best suited to consuming the food resources on the island would survive, breed, and produce offspring with the same beak type.
•genes for the parents beak type were passed to the children.

Question 10

Darwin’s theory of natural selection (1):

Answer 10

•theory of natural selection: evolution takes place because more organisms are produced than can survive, and only the organisms best suited to their environment survive to reproduce and pass on their advantageous traits to their offspring.

Question 11

Darwins theory of evolution by natural selection (2):

Answer 11

•Darwin’s theory of natural selection.
•explained that evolution occurs in five steps:
1. Overproduction.
2. Struggle for existence.
3. Variation.
4. Survival of the fittest.
5. Origin of new species.

Question 12

1. Overproduction:

Answer 12

•the number of offspring produced by a species is more than can actually survive.
•example:
-a single fern produces 50 million spores per year.
-if each of these spores would thrive and survive, in only two generations ferns would cover North America.

Question 13

2. Struggle for existence:

Answer 13

•every living organism faces a constant struggle to survive.
•only a fraction of offspring will survive due to fierce competition for food, mates, shelter, etc.

Question 14

3. Variation:

Answer 14

•individuals of a given species vary.
•only identical twins are the same.

Question 15

4. Survival of the fittest (natural selection):

Answer 15

•nature selects which organisms which will survive based on traits that give them an advantage in the environment.

Question 16

5. Origin of new species:

Answer 16

•the organisms that survive pass on their traits to offspring.
•this eventually can lead to speciation.

Question 17

Comparison of theories (Darwin):

Answer 17

•organisms vary regardless of the environment.
•the environment then determines whether a variation is harmful (die) or helpful (survive).

Question 18

Comparison of theories (Lamarck):

Answer 18

•individuals change to suit their environment.
•change is based on the need or “want” to change.

Question 19

Further evidence of evolution:

Answer 19

•there are 5 lines of evidence that helped Darwin prove that species change over time:
1. Fossil records.
2. Biogeography.
3. Anatomy.
4. Embryology.
5. Molecular biology (biochemistry).

Question 20

Further evidence of evolution:
1. Fossil record:

Answer 20

•fossils found in young layers of rock are much more similar to species alive today.
•fossils appear in chronological order. (Not all organisms appear in the fossil record at the same time).

Question 21

Further evidence of evolution:
2. Biogeography:

Answer 21

•study of the past and present geographical distribution of organisms.
•geographically close environments are more likely to be populated by related species than are locations that are geographically separate but environmentally similar.
•animals on islands have evolved from mainland animals.
•fossils of the same species can be found on the coastline of neighbouring continents.
•closely related species are almost never found in exactly the same location or habitat.

Question 22

3. Anatomy:

Answer 22

•homologous structures: are those that have similar structural elements and origin but may have different functions.
•body parts that have a different structure but perform similar functions, even though the organisms do not have a common evolutionary origin is called analogous structure.
•vestigial structures: rudimentary structures that serve no useful function.
•a reasonable explanation is that they once served some function in an ancient ancestor.

Question 23

4. Embryology:

Answer 23

•the embryos of different organisms exhibit similar stages of embryonic development.
•similarities among embryos in related groups point to a common ancestral origin.
•similarities in the embryos of a lizard, tortoise, pig, and mammals provide evidence of evolution.

Question 24

5. Molecular biology:

Answer 24

•evolutionary relationships among species are reflected in their DNA and proteins.
•provided evidence that helps support the idea of common ancestry and evolution through natural selection.

Question 25

Artificial selection:

Answer 25

•artificial selection: the process of humans selecting and breeding individuals with desired traits.
•used to alter appearance, behaviour, and chemical makeup of plants and animals.