Chapter 3 - Descent with Modifications

Question 1

Aristotle (384-322 BC)

Answer 1

• Species fixed, unchanging
• Scala naturae

Question 2

Linnaeus (1707-78)

Answer 2

• Hierarchical classification
• Binomial nomenclature
• Species fixed, unchanging

Question 3

Biogeography

Answer 3

the distribution of species around the world

Question 4

Fossil record (Cuvier)

Answer 4

evidence of extinction of species and change through time

Question 5

(Hutton & Lyell)

Answer 5

Gradual geological change through time
 Therefore, earth very old!

Question 6

(Malthus)

Answer 6

• Concept of population pressure

Question 7

Lamarck (1744-1829)
o Theory of inheritance of acquired characteristics

Answer 7

holds that an organism experiencing such a modification can transmit such a character to its offspring.

Question 8

Darwin’s voyage

Answer 8

 1831-1836
 Galapagos finches
o Studied 14 species
o Hypothesized that they evolved from common ancestor from mainland
o “One might really fancy that, from an original paucity of birds in this archipelago, one species had been taken and modified for different ends.”

Question 9

Alfred Wallace

Answer 9

-1823—1913
- Naturalist
- Studied biodiversity of Southeast Asia
- Published a paper on evolution by natural selection alongside Darwin’s first published paper in 1958.

Question 10

The Darwin-Wallace Principle of Natural selection

Answer 10

• Individuals within a population vary for one or more characteristics (traits)
• Traits are (to some extent) inherited by offspring from their parents
• More offspring are produced than can survive
   those with traits that improve survival/reproduction leave more offspring
   these favorable traits will accumulate in the population over generations

Question 11

Evolution

Answer 11

a change in the genetic makeup of a population over time (microevolution)

Question 12

Frequency of Alleles

Answer 12

Change in the genetic makeup refers to a change in the frequency of alleles in a population

Question 13

Allele Frequency

Answer 13

the relative abundance of an allele in a population

Question 14

Adaptation

Answer 14

• In evolutionary terms, an adaptation is some heritable trait that improves the odds for surviving and reproducing in a given environment.
• It is the outcome of natural selection.
• Natural selection can only increase or decrease the frequency of an adaptation in a population

Question 15

Fitness

Answer 15

• A way of quantifying an organism’s reproductive success
• 3 components:
   Survival
   Mating success
   Number of offspring per mating

Question 16

POPULATIONS Evolve

Answer 16

• Individuals do not evolve!
• Natural selection acts on populations over many generations
• When the allele frequency in a population has changed, we say that the population has evolved.

Question 17

Evidence For Evolution
Four types of data:

Answer 17

1. Direct observations
2. Homology
3. Fossil record
4. Biogeography

Question 18

Artificial Selection

Answer 18

man, artificially selects for desirable or beneficial characteristics

Question 19

Convergent Evolution

Answer 19

• Organisms evolving under similar environments will evolve similar characteristics.
• Results in evolution of analogous traits in different species
• Occurs when they face similar selection pressures due to similarities in their environments
• Evidence of how natural selection leads to adaptations
• Classic example is convergent evolution of placental and marsupial mammals
   Australian marsupials closely resemble placental mammals on other continents

Question 20

Homology

Answer 20

• Homologous structures - inherited from a common ancestor
• structures that have the same embryonic origin but may have a different function.
• May have different functions in different species
• Provide evidence that organisms are related/descended from a common ancestor

Question 21

Vestigial Structures

Answer 21

• structures with no apparent function. Certain organisms have lost need of appendages, they become useless, and appear to have no function
• Evidence of descent with modification

Question 22

Fossil Record

Answer 22

• shows changes in organisms over time.
• Evidence that organisms have changed over time
• Evidence that organisms we see today evolved from pre-existing species
• Fossil Record provides evidence of transitional species