Chapter 22: Descent with Modification

Question 1

Darwin was inspired to form scientific explanation for what 3 broad observation about life

Answer 1

1. The striking ways in which organisms are suited for life in their environments.
2. the many shared characteristics( unity of life)
3. The rich diversity of life

Question 2

EVOLUTION

Answer 2

.Descent with modification ( by natural selection)

. A change in genetic composition of a population from generation to generation

Question 3

ARISTOLE’S view of species

Answer 3

.That species are fixed ( unchanging).
.Variables exist around a perfect form

. Recognized certain “affinities” ( similarity in
characteristics) among organisms

. Life forms could be arranged on a ladder, or scale, of increasing complexity called SCALA NATURAE ( linear hierarchy)

. Each form of life, perfect and permanent, had its allotted rung on the ladder

. Consistent with the old Testament account of creation, which holds that species wee individually designed by God and therefore perfect.

Question 4

CAROLUS LINNAEUS ( 1707-1778

Answer 4

.swedish physician and botanist

.developed the binomial format for naming species ( genus+species)

.Developed the nested classification system ( vs Aristotle’s linear hierarchy) ( genus, species, kingdom etc>)

Question 5

STRATA( STRATUM)

Answer 5

A rock layer formed when new layers of sediment cover older ones and compress them

Question 6

GEORGES CUVIER ( 1769-1832)

Answer 6

.CATASTROPHISM
. Help to develop PALEONTOLOGY ( The study of fossils)

. When examining strata he noted that the older stratum the more dissimilar they were to present day forms. The top layers were closer to today’s organisms

. Observed from one layer to the next new species appeared while others disappeared

. Opposed evolution

. Instead he explained his findings as
CATASTROPHISM ( The principle that events in the past occurred suddenly and were caused by mechanisms different from those operating in the present)

. Each boundary between strata represented a catastrophe that had destroyed all the species living at the time and the area was soon populated by different species immigrating from other areas.

. New species were explained as coming in from elsewhere

Question 7

JAMES HUTTON (1726-1797) (geologist)

Answer 7

. GRADUALISM
.proposed that the earth’s geologic features could be explained by gradual mechanisms still operating to day (valley’s were created by rivers wearing away at the rocks)
. Vs Catastrophism (rapid change
.Rivers carry sediment into other bodies of water such as seas and swamps and deposit them. Over time sedimentary layers form under the water called strata. these strata contain fossils . As the strata is pushed up the strata and their fossils are exposed. The deeper layers of strata were older.

Question 8

CHARLES LYELL ( geologist) ( 1797-1875)

Answer 8

.UNIFORMITARIANISM
. Incorporated Hutton’s gradual mechanism idea into his principle called UNIFORMITARIANISM ( mechanisms of change are constant over time)

. The same geologic process are operating today as in the past, and at the same rate
.Darwin agreed if geological from slow, continuous actions rather than sudden events then the earth must be old

Question 9

JEAN BAPTIST LAMARK ( french biologist)

Answer 9

. evolutionary change explains patterns in fossils and the match of organisms to their environment.

. 2 principles: 1.USE AND DISUSE : parts of the body that are used extensively become larger and stronger, while those that are not used deteriorate( e.g.. a giraffe stretching its neck)

                2. INHERITANCE OF ACQUIRED  CHARACTERISTICS: stated that an organism could pass these modifications to its offsprings (evolution over time of the giraffe;s long neck from the trait of use is pass down )

. believed that evolution occurred because organisms have an innate drive to become more complex
TRANSMUTATION

Question 10

DARWINS observations

Answer 10

1. Confirmation of Lyell’s Uniformity that the earth was old ( andes earthquake)

2.Galapogos finches where different on each island but were similar to the mainland species. Animal though similar were different species where unique to their island and did not exist any where else in the world.
. ADAPTIVE RADIATION: Divergence of multiple new species from a single ancestral type in a relatively short time.
.The finches’s vaarious beaks and behaviours are adapted to the specific foods available to their island ( cactus, seeds and insects)

Question 11

ADAPTATIONS

Answer 11

inherited characteristics of organisms that enhance their survival and reproduction in specific environments.

Question 12

NATURAL SELECTION

Answer 12

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher traits than other individuals because of those traits.
. It is a mechanism of evolution

Question 13

Darwin’s descent with modification summarized

Answer 13

1. Unity of Life : Organisms share many characteristics. All organism descended from a common ancestor.
2. Diversity of Life: Over millions of years organism living in different habitats accumulated diverse adaptations
3. Connection of an organism and its environment

Question 14

ARTIFICIAL SELECTION

Answer 14

Humans modify other species over many generations by selecting and and breeding individuals that posses desired traits

Question 15

Darwins argument for natural selection as a mechanism for evolution

Answer 15

1. artificial selection
2. Members of a population often vary in their inherited traits
3. All species can produce more offspring than the their environment can support; many fail to survive and reproduce
   Inference: Individuals whose inherited traits give them higher probability of surviving and reproducing in a given environment tend to leave more offsprings
   The unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

Question 16

The four types of data that document the pattern of evolution

Answer 16

1. direct observation of evolution
2. Homology
3. Fossil records
4. Biogeography

Question 17

HOMOLOGY

Answer 17

Similarity resulting from common ancestry

Question 18

HOMOLOGOUS STRUCTUURES

Answer 18

Similar anatomical structure different function

Descent from common ancestry

Question 19

VESTIGIAL

Answer 19

remnants of features that served important functions in the organisms ancestors

Question 20

evolutionary trees

Answer 20

a diagram that reflects evolutionary relationships among groups of organisms
. They are hypotheses that summarize our current understanding of patterns of descent

Question 21

CONVERGENT EVOLUTION

Answer 21

The independent evolutionof similar features in different lineages
. Independent adaption occurring in the same environment, but from different lineages

Question 22

ANALOGOUS

Answer 22

Features resulting from convergent evolution; Same function different ancestor

Question 23

BIOGEOGRAPHY

Answer 23

The geographic distribution of species

Question 24

Continental drift

Answer 24

The slow movement of the earth’s continents overtime

Question 25

PANGEA

Answer 25

the single land mass before the division into continents

Question 26

ENDEMIC

Answer 26

Found no where else in the world