Chapter 22 Reading Quiz

1. Who wrote “On the Origin of Species”?2. What branch of biology is concerned

with naming and classifying life?3. What is the proposed mechanism for

evolution?4. What is the geographic distribution of

a species known as?5. In what types of rocks are fossils

typically found?

1. State the two major points Darwin made in The Origin of Species concerning the Earth’s

biota.

1. Species evolved from ancestral species that were not specially created

2. Natural selection is a mechanism that could result in this evolutionary change

2. Compare and contrast Plato’s philosophy of idealism and Aristotle’s scala naturae.

Plato – idealism/essentialism: believed that there were two coexisting worlds an ideal, eternal, real world and an illusionary imperfect world that humans perceive with their senses

Aristotle – beliefs also excluded evolution- recognized that organisms vary from simple to complex and believed that they could be placed on a scale of increasing complexity (scala naturae)- species fixed and didn’t evolve

3. Describe Carolus Linnaeus’ contribution to Darwin’s theory of evolution.

1707 – 1778; Swedish; sought order in the diversity of life

Father of taxonomy (naming and classifying organisms)- developed binomial nomenclature- hierarchy of taxonomic categories- did NOT imply evolutionary relationships- believed that species were permanent creations

4. Describe Georges Cuvier’s contribution to paleontology.

Cuvier founded the study of fossils or “paleontology”

Realized life’s history was recorded in fossil-containing strata and documented succession

Understood that extinction had been a common occurrence in the history of life science as new species appeared and others disappeared

5. Explain how Cuvier and his followers used the concept of catastrophism to oppose evolution.

Catastrophism theory that major changes in the earth’s crust are the result of catastrophic events rather than from gradual processes of change

Proposed that there were periodic localized catastrophes resulted in mass extinctions

After local flora and fauna had become extinct, the region would be repopulated by foreign species

6. Explain how the principle of gradualism and Charles Lyell’s theory of uniformitarianism influenced Darwin’s ideas about evolution.

Gradualism principle that profound change is the cumulative product of slow, continuous processes

Uniformitarianism theory that geological processes are uniform and have operated from the origin of the earth to the present

Darwin rejected uniformitarianism, but was influenced by that the earth must be ancient and slow and subtle processes persist and cause substantial change

7. Describe Jean Baptiste Lamarck’s model for how adaptations evolve.

…mechanism by which specific adaptations evolve:1. Use & disuse those body organs used

extensively to cope with environment become larger and stronger while those not used deteriorate

2. Inheritance of acquired characteristics: the modifications an organism acquired during its lifetime could be passed along to its offspring- was incorrect, yet evolution is the best explanation and the earth is ancient- adaptation to the environment is a primary product of evolution

8. Describe how Charles Darwin used his observations from the voyage of the HMS Beagle to formulate and support his theory of evolution.

1. All species have such great potential fertility that their population size would increase exponentially is all individuals that are born reproduced successfully

2. Populations tend to remain stable in size, except for seasonal fluctuations

3. Environmental resources are limited4. Individuals of a population vary extensively

in their characteristics; no two are alike5. Much of this variation is heritable; survival is

not random – unequal ability

9. Describe how Alfred Russel Wallace influenced Charles Darwin.

Wallace was a specimen collector in the East Indies and sent a letter that detailed a theory of natural selection almost identical to Darwin’s

Darwin evaluated the theory and sent it to publication

Darwin is considered the main author of the idea because he developed and supported natural selection much more extensively than Wallace

10. Explain what Darwin meant by the principle of common descent and “descent with

modification”.

Principle of common descent closely related animals share a recent common ancestor, etc.

Descent with modification perception that there is a unity in life with all organisms related through descent as diverse adaptations accumulate through years

11. Explain what evidence convinced Darwin that species change over time.

Perceived from studying the 14 types of finches from the Galapagos that the origin of a new species and adaptation were closely related processes, as new species could arise from an ancestral population by gradually accumulating adaptations to a different environment

Example: isolated populations of a species- food sources

12. State, in your own words, three inferences Darwin made from his observations, which led him to propose natural selection as mechanism

for evolutionary change. 1. Production of more individuals than the

environment can support leads to a struggle for existence among individuals of a population, with only a fraction of offspring surviving each generation

2. Survival in the struggle for existence is not random but depends in part on the hereditary constitution of the surviving individuals

3. The unequal ability of individuals to survive and reproduce will lead to a gradual change in a population with favorable characteristics accumulating over generations

13. Explain why variation was so important to Darwin’s theory.

Variation and overproduction in populations make natural selection possible

- the end product of natural selection is adaptation of organisms to their environments- variations in a population arise by chance, but natural selection is not a chance phenomenon

14. Explain how Reverend Thomas Malthus’ essay influenced Charles Darwin.

Already aware of the struggle for existence caused by overproduction

The capacity for overproduction is common to all species, and only a fraction of new individuals complete development and leave offspring of their own; the rest die or are unable to reproduce

15. Distinguish between artificial selection and natural selection.

Natural selection variation and overproduction in populations – the most fit individuals pass on their genes; results from environmental editing

Artificial selection breeding of domesticated plants and animals have modified species

Conclusion if so much change is achieved by artificial selection in a short period of time (humans), natural selection should be capable over hundreds of thousands of years

16. Explain why the population is the smallest unit that can evolve.

Population = a group of interbreeding individuals belonging to a particular species and sharing a common geographic area

Evolution can only be measured as change in relative proportions of variations in a population over several generations

17. Using some examples, explain how natural selection results in evolutionary

change. Finch beaks on the Galapagos

- average beak depth oscillates with rainfall- natural selection is situational

Butterfly reproduction - they choose different plants depending on where they were laid

Antibiotic resistance in bacteria Body size of guppies exposed to different

predators

18. Explain why the emergence of population genetics was an important turning point for

evolutionary theory.

Natural selection is a consequence of interactions between individual organisms and their environment but INDIVIDUALS do NOT evolve- acquired characteristics are not inherited

Evolutionists must distinguish between adaptations an organism acquires during it’s lifetime and those inherited adaptations that evolve in a population over many generations as a result of natural selection

19. Describe the lines of evidence Charles Darwin used to support the principle of common

descent.

1. Biogeography – the geographical distribution of species2. Fossil record – appearance of branches in the phylogenetic

tree3. Comparative anatomy – anatomical similarities among

species grouped in the same taxonomic category are a reflection of their common descent

4. Comparative embryology – closely related organisms go through similar stages in their embryonic development

Theory “ontogeny recapitulates phylogeny” the embryonic development of an individual organism is a replay of the evolutionary history of the species

5. Molecular biology – an organism’s hereditary background is reflected in its genes and their protein products - the closer two species are taxonomically, the higher the % DNA in common

20. Describe how molecular biology can be used to study the evolutionary relationships among

organisms.

Closely related species have proteins of similar amino acid sequences (resulting from inherited genes)

Substantiated Darwin’s idea that all forms of life are related to some extent through branching descent from the earliest organisms

21. Explain the problem with the statement that Darwinism is “just a

theory”. Flawed because of:

1. Modern species evolved from ancestral forms2. The mechanism for evolution is natural selection ( Darwin’s two claims)

That species EVOLVE (change over time) is FACT, the mechanism (how this occurs) is THEORY

22. Distinguish between the scientific and colloquial use of the word “theory”.

In science, “theory” is very different from the colloquial use of the word, which comes closer to what scientists mean by a hypothesis or educated guess

Unifying concepts do not become scientific theories unless their predictions stand up to thorough and continuous testing by experiment and observation