Descent With Modification Lecture 18

Question 1

what does natural selection result in

Answer 1

adaptive evolution

Question 2

before Darwin, what did Aristotle think

Answer 2

– Viewed species as fixed and unchanging
– Life could be arranged on a scale of increasing complexity
* “scala naturale”

Question 3

what did the old testament say regarding this

Answer 3

Holds that species were individually designed by God

Question 4

what did Carolus Linnaeus say regarding this, who was she ?

Answer 4

– Was a founder of taxonomy,
– Did not attribute resemblances among species to evolutionary kinship,
* Attributed similarities rather to the pattern of their creation

Question 5

what helped lay the groudwork for Darwin’s ideas

Answer 5

the study of fossils (paleontology)

Question 6

where are remains or traces of the organisms usually found

Answer 6

• sedamentary rocks
• in layers (strata)

Question 7

what do fossils show

Answer 7

succession of organisms have populated earth through time

Question 8

what did cuvier note about stratas

Answer 8

the older the strata, the more dissimilar the fossils from modern life

Question 9

what is catastrophism theory

Answer 9

speculating that boundaries between strata were due to local floods or droughts that destroyed the species present.

Question 10

what did JB Lamarck propose before Darwin

Answer 10

Organisms pass traits to offspring through use and disuse
* parts of the body used extensively become stranger & larger, while those not used deteriorate
—- change in environment changes behavior

Question 11

according to Lamarck, how did organisms pass traits to offsprings

Answer 11

disuse

Question 12

what did Hutton propose before Darwin

Answer 12

proposed a theory of gradualism
– Gradualism: profound change can take place through the cumulative effect of slow but continuous processes

Question 13

what did Lyell propose before Darwin

Answer 13

perceived that changes in Earth’s surface can result from slow continuous actions still operating today
– i.e. valleys formed by rivers wearing away at rocks

Question 14

what did Darwin develop his theory on

Answer 14

i) Malthus’ essay: Struggle for existence
ii) Lyell’s Principles of Geology
iii) Principles of artificial selection also influenced Darwin’s theories
iv) His data (what he saw in the Galapagos)

Question 15

explain how struggle for existence helped Darwin

Answer 15

Thomas Robert Malthus
* Population growth not always desirable
* Conflict between population growth and food supply generates famine, disease, war, which inevitably break population growth

Question 16

explain how Lyell’s principle helped Darwin

Answer 16

• he experienced geologic change (earthquakes, rocks thrust upwards, earth not static)
• Reinforced Darwin’s acceptance of Lyell’s
  ideas
• doubt about the traditional view of a young and
  static Earth.

Question 17

explain how artificial selection helped Darwin

Answer 17

Humans have modified domesticated plants and animals in just a few generations by selecting individuals with the desired traits for breeding.

therefore, If artificial selection can achieve large change in a relatively short period of time, Darwin reasoned that natural selection should be capable of modification over thousands of generations.

Question 18

what is Darwin’s data from the Galapagos

Answer 18

• voyage was the basis of the theory of evolution
• Darwin observed various adaptations of plants and animals that inhabited the many diverse environments
  Compared animals on islands (ex: Galapagos) with those of mainland.
• Impressed by similarities and ALSO distinct differences

Question 19

how long was Darwin’s exploration

Answer 19

5 years

Question 20

what did Darwin hypothesis during his voyage

Answer 20

that the islands had been colonized by plants and animals from the mainland that had subsequently diversified on the different islands.

Question 21

when did Darwin write long essay on origin of species and naturel selection

Answer 21

1840s (relunctant to publish)

Question 22

When did Alfred Russel Wallace (1823–1913), a young naturalist, send Darwin a manuscript containing a theory of natural selection essentially identical to Darwin’s

Answer 22

1858

Question 23

when did Darwin publish the origin of species

Answer 23

1859

Question 24

check how naturel selection works in slides **

Question 25

what is the smallest group that can evolve

Answer 25

population (individuels do not evolve)

Question 26

on what traits can naturel selection act

Answer 26

heritable traits

Question 27

what is the evidence of Darwin’s theory

Answer 27

a) Natural Selection in action (examples,
including ‘artificial selection’)
b) Homology (anatomy, development and molecular) c) Convergent evolution (Analogous features)
d) Biogeography
e) Fossils

Question 28

what is homology

Answer 28

similarity resulting from common ancestry

Question 29

what are homologous structures

Answer 29

anatomical resemblances that represent variations on a structural theme that was present in a recent common ancestor but diverged to have different fucntions (divergent evolution)

Question 30

what is a vestigial organ

Answer 30

seemingly useless organs *left over from ancestors
proves that organism evolved from ancestors in which organs were functional
(hind limb bones in snakes shows descendant from tetrapods)

Question 31

what does the universal code of DNA prouve

Answer 31

evidence for a common ancestor

Question 32

what does Analogous mean

Answer 32

characters are similar, but not derived from a common ancestor

Question 33

what do analigous features demonstrate

Answer 33

organisms with separate ancestors may adapt in similar ways to similar environment

Question 34

explain Biogeography

Answer 34

Species tend to be more closely related to other species from the same area than to other species that live in different areas
- suggests a common ancestor adapts to various habitats
- This resulted in populations becoming isolated in different environments evolving differently

Question 35

what is a pangea

Answer 35

Continents once joined together, as time passed, each continental plate moved (plate tectonics)

Question 36

how do fossil records contribute to Darwins theory

Answer 36

Succession of forms observed in the fossil record consistent with other inferences about the major branches of descent in the tree of life

Question 37

what is neo-darwinism

Answer 37

modern version of Darwinian evolutionary theory which incorporates Mendelian genetics.

Neo-Darwinism postulates that natural selection acts on the heritable (genetic) variations within individuals in populations
* and that mutations (especially random copying errors in DNA) provide the main source of these genetic variations.