Chapter 20- Biological Evolution

Question 1

History on Theory of Evolution

Answer 1

The established theory stayed that organisms do not change and Earth was only a few thousand years old

Question 2

George Buffon

Answer 2

Suggested that vestigial structures, the useless parts, must have functioned in the ancestors of the organisms.

Buffon was the first to ever write and publish that living things do change.

Question 3

Georges Cuvier

Answer 3

To explain the fossilized remains, Cuvier proposed the theory of catastrophism.
Whenever a new stratum showed new fossils, a sudden dramatic event had caused a mass extinction in that region and organisms in the surrounding regions will move in.

Question 4

Jean Baptiste de Lamarck

He proposed two mechanisms that caused evolutionary changes.

Answer 4

1. Principle of use and disuse stated that the body parts either got bigger with use or smaller with disuse.
2. Inheritance of acquired characteristics stated that any changes an organism acquires during its lifetime will be passed on to the offspring.

Question 5

James Hutton and Charles Lyell

Answer 5

Hutton proposed that Earth’s major geological features formed slowly and continuously over long periods of time.

Lyell extended Hutton’s ideas and was the first scientist to propose that Earth is millions of years old.

Question 6

Darwin

Answer 6

Studied artificial selection, the process by which humans choose which traits that will be passed on to the offspring.

Question 7

Darwin’s Eureka moment when he read…

Answer 7

A book by Thomas Malthus called Essay on the Principle of Population.

Malthus proposed that the human population growth is limited by availability of resources.

Individuals will compete for limited food resources, some will starve.

Question 8

Darwin- The environment

Answer 8

“Chooses” members of the population with the adaptive traits that will allow the members to survive and reproduce.
When the surviving members reproduce, those adaptive traits will be passed on to the offspring (natural selection)
By favoring individuals that are well adapted to the environments they live in, natural selection causes species to change over time.

Question 9

Evidences used today in evolutionary biology

Answer 9

1. Natural selection
2. Fossil record
3. Biogeography

Question 10

1. Natural Selction

Answer 10

By following characteristics of population over time, researchers have observed how natural selection alters such populations in response to environmental changes.

Example: mosquitos becoming resistant to pesticide

Question 11

2. Fossil record

Answer 11

Fossil record shows the continuity in the morphological characteristics.

Example: Evolution of birds can be traced back to the non flying dinosaur ancestor Archaeopteryx lithographica

Question 12

3. Biogeography

Answer 12

Biogeography is the study of the geographical distribution of extinct and living species.

Question 13

Homology may be

Answer 13

1. Anatomical
2. Developmental
3. Molecular

Question 14

Anatomical

Answer 14

Homologous structures are derived from a common ancestor

Example: Forelimbs of all four-legged vertebrates are homologous because they evolved from a common ancestor.

Question 15

Developmental

Answer 15

Species that differ as adults often bear striking similarities during the embryonic stages.

Example: Early embryos of four-legged vertebrates are similar because they all evolved from a common ancestor.

Question 16

3. Molecular

Answer 16

Similarities in cells at the molecular level show that living species evolved from a common ancestor.

Example: p53 gene plays a role in preventing cancer.
Evolution also occurs at the genomic level involving changes in chromosome structure and number.