Descent with Modification

Question 1

Two main ideas

Answer 1

1. Today’s organisms descended from ancestral species that were different from modern species
2. Natural selection is the mechanism for this evolutionary change

Question 2

Natural selection results _________-

Answer 2

Natural selection results in adaptive evolution

Question 3

Natural selection

Answer 3

Population can change over time if individuals that possess certain heritable traits leave more offspring

Question 4

Evolution

Answer 4

Earth’s many species are descendants of ancestral species that were different from the present-day species

Question 5

Evolution = _______________

Answer 5

Evolution = descent with modification

Question 6

Evolution as a pattern and as a process

Answer 6

• Pattern of evolutionary change → revealed by data from many scientific disciplines
• These data are facts → observations about the natural world

Question 7

Aristotle

(3)

Answer 7

• Viewed species as fixed (unchanging)
• Recognized certain “affinities” among organisms
• Life forms could be arranged on a ladder of increasing complexity → Scala naturae

Question 8

Natural theology (Judeo-Christians religions)

Answer 8

• species were individually designed by a creator and therefore perfect
• Perfect match of organisms to their environment → interpreted as evidence that The Creator had designed each species with a purpose

Question 9

Fossils → Older the stratum, _________________

Answer 9

Fossils → Older the stratum, the more dissimilar its fossils were to current life forms

Question 10

Catastrophism

(2)

Answer 10

• Events in the past occurred suddenly + were caused by mechanisms different than those operating in the present
• Boundaries between strata → local floods or droughts that destroyed species present

Question 11

Gradualism

Answer 11

Profound change can take place through the cumulative effect of slow but continuous processes

Question 12

conclusion of gradualism

Answer 12

if geological changes result from slow, continuous processes rather than sudden events, Earth is far older than the 6,000 years estimated by the bible

Question 13

Lamark → explained two principles

Answer 13

1. Use and disuse: parts of the body that are used extensively become larger and stronger, while those that are not used deteriorate
2. Inheritance of acquired characteristics: an organism could pass these modifications to its offspring

Question 14

Lamark - Thought evolution happens because __________

Answer 14

Thought evolution happens because organisms have an innate drive to become more complex

Question 15

lamark: Had the right _____, but the wrong ________

Answer 15

Had the right idea (match of organisms to their environment → gradual evolutionary change), but the wrong mechanisms

Question 16

Voyage of the Beagle

Answer 16

5-year exploration that Allowed Dawin to study adaptation + gather proof he would incorporate into the theory of evolution

Question 17

Voyage of the Beagle - conclusion

Answer 17

Adaptations to the environment + origin of new species are a closely related process

Question 18

what pushed Darwin to publish

Answer 18

Got sent a manuscript containing a theory of natural selection identical to his

Question 19

NS:

All species produce more offspring than ____________

Answer 19

All species produce more offspring than their environment can support

Question 20

NS:

Environmental resources are limited

Answer 20

Production of more individuals than the environment can support → struggle for existence
* Competition for limited resources

Question 21

NS:

Members of a population vary extensively in their characteristics

Answer 21

No two individuals are exactly alike

Question 22

Natural selection may act on these variables if:

(2)

Answer 22

1. They are heritable
2. They affect the individual’s ability to survive + reproduce

Question 23

Natural selection occurs through interactions between ________ + __________

Answer 23

Natural selection occurs through interactions between organisms + environment

Question 24

Individuals DO NOT EVOLVE

Answer 24

it is the population that evolves over time

Question 25

Natural selection can amplify or diminish only:

Answer 25

Natural selection can amplify or diminish only **those heritable traits that differ among the individuals in a population**

Question 26

Natural selection, perfect organisms?

Answer 26

Natural selection **doesn’t create perfect organisms** Allows organisms to **adapt to their environment**

Question 27

Darwin developed his theory based on: | (4)

Answer 27

1. Mathus’ essay: Struggle for existence 2. Lyell’s principles of geology 3. Principles of artificial selection 4. His data (what he saw in the Galapagos)

Question 28

Struggle for existence

Answer 28

While a population has the potential of growing exponentially, limited resources will naturally limit population growth

Question 29

Uniformitarianism

Answer 29

Mechanisms of change are constant over time - Same geologic processes are operating today as in the past + at the same rate

Question 30

Artificial selection

Answer 30

Humans have modified domesticated plants + animals in just a few generations by selecting individuals with the desired traits for breeding * Artificial selection can achieve large changes in relatively short period of time * Natural selection THEN capable of modifications over thousands of generations

Question 31

Darwin argued that similar processes occur in nature (similar to aritficial selection) | (based on 2 obs.)

Answer 31

a) Members of a population often vary in their inherited traits b) All species can produce more offspring than their environment can support

Question 32

Evidence for Darwin's theory | (5)

Answer 32

1. Natural selection in action 2. Homology 3. Convergent evolution 4. Biogeography 5. Fossils

Question 33

Homology

Answer 33

the similarity resulting from common ancestry

Question 34

Vestigial organs

Answer 34

* seemingly useless organs or structures (“leftovers from ancestors”) * Indicate that the organism evolved from ancestors in which the organ was functional

Question 35

why do vertigial organs tend to persist

Answer 35

no selective pressure to eliminate them

Question 36

# homology Comparing early stages of development in different animal species

Answer 36

Reveals **additional anatomical homologies**not visible in adult organisms

Question 37

# homology Molecular

Answer 37

All forms of life use the same genetic language of DNA and RNA Likely that all species descended from common ancestors that used this code

Question 38

Convergent evolution = analogous structures

Answer 38

Characteristics are similar, but not derived from a common ancestor

Question 39

Homologous vs. Analogous

Answer 39

* Analogous features share similar function but **NOT common ancestry** * Homologous features share common ancestry but **NOT necessarily similar function**

Question 40

Biogeography

Answer 40

Species tend to be more closely related to other species from the same area than to other species that live in different areas

Question 41

Pangea

Answer 41

continents once joined together, isolated as time passed

Question 42

Fossils

Answer 42

**A replica in stone of original organism** (formed when minerals in H2O replace materials in bone + tissue)

Question 43

Succession of forms observed in the fossil record consistent with __________

Answer 43

Succession of forms observed in the fossil record consistent with **proposed ‘order’ of evolution**

Question 44

is natural selection just a theory

Answer 44

Natural selection is a **unifying theory** -- The pattern of evolution has been documented directly + is supported by a lot of evidence