4.1 Darwin's Theory Of Natural Selection

Question 1

Jean-baptiste Lamarck

Answer 1

Fossils modified versions of modern species

Inheritance of acquired characteristics

Transformationalism

Question 2

Transformationalism

Answer 2

The use or disuse of a body part results in heritable change

Question 3

Can affect gene expression and be inherited by offspring

Answer 3

DNA methylation

Question 4

James Hutton

Answer 4

Uniformitarianism

Question 5

Uniformitarianism

Answer 5

1. The basic laws of physics and chemistry are constant over time
2. Natural forces that cause past geological events are similar to those still occurring

Question 6

Charles Lyell

Answer 6

Principles of geology based on uniformitarianism

Question 7

Charles Darwin

Answer 7

Applied uniformitarianism to history of life on earth

Used

Question 8

Thomas Robert Malthus

Answer 8

Human populations increase at an exponential rate, eventually exceeding the capacity of their environment

Positive checks: increasing death rate

Preventative checks: decreasing birth rate

Natural outcomes of overpopulation: poverty, food/famine, disease

Question 9

Global differences

Answer 9

Species in one part of the world look. very different from species in another part. Species can be limited to specific pars of the world.

Question 10

Local differences

Answer 10

Species vary across geographic areas. Similar organisms vary depending on ecological niche.

Question 11

Temporal differences

Answer 11

Species change over time causing differences among members of the same species.

Question 12

Ernst Walter Mayr

Answer 12

Evolutionary biologist separated Darwinian evolution into five separate theories:

• perpetual change
• common descent
• multiplication of species
• gradualism
• natural selection

Question 13

Perpetual change

Answer 13

The living world is in a constant state of flux without a fixed state. Supported by fossil records.

Question 14

Common descent

Answer 14

All life originated from a shared ancestor. Supported by comparative anatomy, developmental biology, embryology, and more recently molecular biology.

Question 15

Multiplication of species

Answer 15

New species evolve by existing species splitting and transforming. Geographically isolated populations can diverge and become separate species.

Question 16

Gradualism

Answer 16

Many small, steady changes produce notable trait differences over a long period of time. Small genetic change that produces a drastic physical change is rare and tends to be harmful.

Question 17

Natural selection

Answer 17

Adaptations that give an advantage are favored. Individuals of a population are in continuous struggle to survive due to limited natural resources. Individuals vary in reproductive success which leads to heritable adaptations over time.

Question 18

Fitness

Answer 18

Ability of an individual to pass along genes to the next generation in a certain environment.

Question 19

Homologous structures

Answer 19

Physical features that share form and/or function as a result of common ancestry

Question 20

Vestigial structures

Answer 20

Physical features that remain in a species but have no current function

Question 21

Analogous structures

Answer 21

Arise through convergent evolution when different, unrelated organisms live in similar environments.

Question 22

Ontogeny

Answer 22

Development of an individual over the course of its life

Question 23

Phylogeny

Answer 23

How a species evolves over time

Question 24

Recapitulation

Answer 24

Evolution occurs by adding new stages at the end of the development of an individual

“Ontogeny recapitulates phylogeny” - Darwin

Eg. A human embryo begins as a fish, develops into and amphibian, a reptile, and an early mammal, before becoming human.

Question 25

Modern synthesis

Answer 25

Combination of Mendelian genetics and Darwinian evolution, coined by Julian Huxley in 1942

Defines evolution as changes in allele frequencies within populations and identifies several forces of evolution the influence those changes

Question 26

Biogeography

Answer 26

Explains the spatial distribution of organisms and abiotic factors that influence their distribution

Question 27

Endemic species

Answer 27

Species that are native and restricted to a specific area

Question 28

Homeotic genes

Answer 28

Regulate anatomical development. Guide the differentiation of anterior and posterior body regions early in the development of an organism.

Consider what a mutation might cause

Question 29

Homeobox

Answer 29

An area of DNA in a homeotic gene that encodes a protein that binds to other genes to modify their expression during the early stages of development

Question 30

Toolkit genes

Answer 30

Highly conserved genes that code for critical aspects of early development, such as homeotic and homeobox genes

Question 31

Artificial selection

Answer 31

Humans artificially produce organisms with desirable traits

Changes in traits happen much more quickly than with natural selection

Question 32

Edward Lewis, Eric Wieschaus, Chritian Nusslein-Volhard

Answer 32

Shared the 1995 Nobel Prize for their work on homeotic genes through studying the development of the fruit fly, Drosophila

Question 33

Peter and Rosemary Grant

Answer 33

Spent many years studying the finches on the Galápagos Islands

Noticed that beak sizes decreased over generations as weather shifted and caused smaller seeds to be more common than larger seeds, beak sizes increased again over several generations as weather pattern normalized and smaller seeds became less common

Question 34

Peppered moth

Answer 34

Normally white with black specking to camouflage when resting during the daytime on lichen-covered trees

Towards the end of the Industrial Revolution a melanic black mutant form appeared and quickly reached frequencies as high as 98% due to sooty pollution darkening the trees

Birds could easily find the light-colored moths on the dark trees

Light-colored moths became dominant again when pollution was better controlled