Organic evolution ch 6

Question 1

Who proposed the
Inheritance of Acquired Characteristics?

Answer 1

Jean Baptiste de Lamarck

Question 2

What is Inheritance of Acquired Characteristics?

Answer 2

was engagingly simple: organisms, by striving to meet the demands of their environments, acquire adaptations and pass them by heredity to their offspring.

Question 3

We call Lamarck’s concept of evolution ________________, be- cause it claims that as individual organisms transform their charac- teristics through the use and disuse of body parts, heredity makes corresponding adjustments to produce evolution.

Answer 3

transformational

Question 4

Darwin’s theory is based on __________ in a population, not at the individual level

Answer 4

variation

Question 5

Who proposed the Principle of Uniformitarianism

Answer 5

Sir Charles Lyell

Question 6

What are the two principles of Uniformitarianism?

Answer 6

(1) that the laws of physics and chemistry have not changed throughout the history of the earth.
(2) that past geological events occurred by natural processes similar to those observed today.

Lyell showed that natu- ral forces, acting over long periods of time, could ex- plain the formation of fossil-bearing rocks

Question 7

________ showed that natu- ral forces, acting over long periods of time, could ex- plain the formation of fossil-bearing rocks

Answer 7

Lyell

Question 8

Lyell’s book, “________ __ _________” greatly influenced Darwin

Answer 8

Principles of Geology

Question 9

______ ______ _______
independently came up
with the idea of natural
selection and wrote to
Darwin

Answer 9

Alfred Russel Wallace

Question 10

how did foccels contribute to darwin’s theory of evolution?

Answer 10

they show that life on earth was once different from life found on earth today

Question 11

how did Malthus’ essay contribute to darwin’s theory of evolution?

Answer 11

-Malthus’ work made Darwin realize the importance of overpopulation and how it was necessary to have variability in different populations.
-Darwin also used Malthus’ ideas to use competition as well as the survival in numbers idea to come up with his full idea of natural selection.

Question 12

how did animal breeding contribute to darwin’s theory of evolution?

Answer 12

-Breeders of pigeons, dogs, and cattle inspired Darwin’s ideas about selection.
-By choosing which animals reproduced, breeders could achieve remarkable changes and diversity in a relatively short time.
-Variations in traits were clearly abundant and heritable.

Question 13

how did geographic distribution of similar animals. contribute to darwin’s theory of evolution?

Answer 13

-you would find closely related yet different species living in a geographic region as they spread into nearby habitats an evolve, as Darwin’s theory states.

Question 14

Main Points of Darwinian Evolution:

Answer 14

1. Change over time (perpetual change; long geological time)
2. Descent from common ancestor
    Species arise and go extinct (trends in diversity)
    Principle of homology
3. Evolution is gradual
    Evidenced by fossils; intermediate steps exist
4. Changes occur in populations not individuals
5. Natural Selection is the mechanism
    Requires: Variation, Heritability, Competition (differential survival)

Question 15

• The world is not constant or cycling; always changing
• Evidenced by fossils; record is incomplete
• Intermediates can be found

Answer 15

1. Perpetual change

Question 16

• Fossils in layers; older at the bottom, newer at the top
• Some fossils are indicators of specific geological time (Eons,
  Eras, Periods and Epochs)
• Accurate dating of rocks did not exist until the 1940’s

Answer 16

2. Geological Time “law of stratigraphy”

Question 17

Darwin proposed that all plants and animals have descended from an ancestral form into which life was first breathed. Life’s history is depicted as a branching tree, called a_________.

Answer 17

phylogeny

Question 18

What is it called when structures share evolutionary origin?

Answer 18

Homology

Question 19

Darwin recognized the major source of evidence for common descent in the concept of _______

Answer 19

homology

Question 20

development of an organism throughout life

Answer 20

Ontogeny

Question 21

Evolutionary change can occur by changing the timing of development

Answer 21

Heterochrony

Question 22

Paedomorphosis

Answer 22

Ontogeny shortened = adult
descendants look like juveniles

Question 23

Size and shape of beaks in
finches depends on the
timing of genetic expression is an example of ___________

Answer 23

Heterochrony

Question 24

_______(“in another land”) populations of a species are those that occupy separate geographical areas. Because of their geo- graphical separation, they cannot interbreed, but would be ex- pected to do so if the geographic barriers between them were removed. If populations are _________ immediately preceding and during evolution of reproductive barriers between them, the re- sulting speciation is called _________ ________ or geographic speciation.

Answer 24

allopatric
allopatric speciation

Question 25

Allopatric speciation begins when a species splits into two or more geographically separated populations. This splitting can hap- pen in either of two ways: _________ ________ or _______ ________

Answer 25

by vicariant speciation or by a founder event.

Question 26

Vicariant speciation

Answer 26

Vicariant speciation is initiated when climatic or geological changes fragment a species’ habitat, producing impenetrable barriers that separate different populations geographically.

Question 27

sympatric speciation

Answer 27

-(“same land”) -different individuals within a species become specialized for occupying different compo- nents of the environment. By seeking and using very specific habitats in a single geographic area, different populations achieve sufficient physical and adaptive separation to evolve reproductive barriers.

Question 28

Hybridization

Answer 28

The occurrence of mating between divergent populations is called hybridization and offspring of these matings are called hybrids (see Figure 6.20). By studying the genet- ics of hybrid populations, we can identify the genetic bases of repro- ductive barriers. divergent population-the process in which two or more populations of an ancestral species accumulate independent genetic changes (mutations) through time

Question 29

parapatric speciation

Answer 29

when a species is spread out over a large geographic area, but only reproduces with local species, resulting in the development of a new species.

Question 30

Example of allopatric speciation

Answer 30

Geologically: Allopatric speciation occurs when two groups of organisms are separated by a physical or geographic barrier. Common examples of these barriers include mountain ranges, oceans, and even large rivers. Animal example: Allopatric speciation due to geographic separation: The northern spotted owl and the Mexican spotted owl inhabit geographically separate locations with different climates and ecosystems. The owl is an example of allopatric speciation.

Question 31

Example of Vicariant speciation

Answer 31

For example, a mammalian species inhabiting a lowland forest could be divided by uplifting of a mountain barrier, sinking and flooding of a geological fault, or climatic changes that cause prairie or desert conditions to encroach on the forest. Formation of the isthmus of Panama sepa- rated populations of the sea urchin genus Eucidaris into separate Caribbean and Pacific Ocean isolates, leading to formation of the pair of species shown in Figure 1.5D.

Question 32

Example of sympatric speciation

Answer 32

For example, cichlid species of African lakes are very dif- ferent from each other in their feeding specializations. In many para- sitic organisms, particularly parasitic insects, different populations may use different host species, thereby providing the physical sepa- ration necessary for reproductive barriers to evolve

Question 33

Example for Hybridization

Answer 33

By studying the genet- ics of hybrid populations, we can identify the genetic bases of repro- ductive barriers. Biologists often distinguish between reproductive barriers that impair fertilization (premating barriers) and those that impair growth and development, survival, or reproduction of hybrid individuals (postmating barriers). Premating barriers cause members of diver- gent populations either not to recognize each other as potential mates or not to complete the mating ritual successfully. Details of the horn structures of African antelopes (see Figure 6.11) are important for recognizing members of the same species as potential mates

Question 34

Example for parapatric speciation

Answer 34

An increase in temperature on a Caribbean is- land, for example, might cause part of a wet tropical forest to be- come a dry, sandy one. A lizard species occupying the formerly wet forest might become divided into geographically adjacent wet and dry forest populations.

Question 35

Describe the five main observations that support natural selection.

Answer 35

1. Perpetual change * The world is not constant or cycling; always changing * Evidenced by fossils; record is incomplete * Intermediates can be found 2. Geological Time “law of stratigraphy” * Fossils in layers; older at the bottom, newer at the top * Some fossils are indicators of specific geological time (Eons, Eras, Periods and Epochs) * Accurate dating of rocks did not exist until the 1940’s #3 Descent from a Common Ancestor Three trends in horses: * Tendency to increase body size. * Reduction of toes. * Elaboration of molars. #4 Changes Occur in Populations not Individuals Variability in beak depth in medium ground finches, Geospiza fortis  There is variability in populations 5. Natural Selection is the mechanism -Impact of a major drought in 1977 affected plants and animals Only large, hard seeds survived -Finches with larger beaks are better adapted to eat large, hard seeds  Differential survival (competition)

Question 36

Gradualism

Answer 36

Darwin’s theory of gradualism opposes arguments for the sudden origin of species. Small differences, resembling those that we ob- serve among organisms within populations today, are the raw mate- rial from which the different major forms of life evolved. This theory shares with Lyell’s uniformitarianism the notion that we must not explain past changes by invoking unusual catastrophic events that are not observed today.

Question 37

punctuated equilibrium

Answer 37

- the hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change. -to explain the discontinuous evolutionary changes observed throughout geological time. Punctuated equilibrium states that phenotypic evo- lution is concentrated in relatively brief events of branching specia- tion, followed by much longer intervals of morphological evolutionary stasis (see Figure 6.26).

Question 38

Macroevolution

Answer 38

Macroevolution describes large-scale events in organic evolu- tion.

Question 39

_________is the study of genetic change occurring within natu- ral populations.

Answer 39

Microevolution

Question 40

6.9. What defines a mass extinction?

Answer 40

When we study evolutionary change on an even larger timescale, we observe episodic events in which large numbers of taxa go extinct simultaneously.