Chapter 11: Evolution

Evolution

the continuous process through which species change over time.

Jean-Baptiste Lamarck

inherited of acquired characteristics

Who wrote Natural selection?

Charles Darwin and Alfred Wallace.

What are the natural selection principles?

1. characteristics are inherited from parent to offspring.

2. more offsprings are produced than are able to survive.

3. offsprings vary among each other in regards to their characteristics.

Darwin and Wallace’s understanding that resources for survival are limited and result in competition was influenced by whose essay?

Thomas Malthus

James Hutton’s proposal that geological change occured gradually over long periods is known as?

Gradualism.

The presence of pelvic bones in some species of snakes despite having no legs, is an example of?

Vestigial structures.

when can natural selection occur?

when there is variation or differences among individuals in a population.

How does genetic diversity happens in a population?

mutation and sexual reproduction and crossing over.

What is mutation?

the ultimate source of new alleles in any population.

What is adaptation?

heritable trait that increases survival and reproduction if the environment changes.

What is Genetic Drift?

random fluctuation in allele frequencies, in small populations.

Founder effect

population leaves to start a new population in a new location or divided by a physical barrier.

Gene flow

the flow of alleles in and out of population, migration of individuals or gametes.

Vestigial Structures

structures with no function.

Example of a vestigial structure.

pelvic bones on snakes.

Convergent Evolution

Evolution of different traits from a common ancestor.

Speciation

Formation of two species from one original species.

How does speciation occur?

1. two new populations must be formed from one original population.

2. must evolve that it becomes impossible for the two new populations to interbreed.

Allopatric Speciation

Geographic separation of population.

Sympatric Speciation:

Same homeland while remaining in one location.

Gene Flow:

The movement of alleles between populations via migration.

Dispersal

Species move to a new geographic area.

Vicariance

natural situation that physically divide organisms.

Adaptive Radiation

where one species radiates out to form several other species adaptive to niche or isolated habitat.

What is an example of Adaptive Radiation?

hawaiian honeycreepers.

Polyploidy

a condition in which cell, organism has an extra set, or sets of chromosomes.

What are the two types of polyploidy?

Autopolyploidy, Allopolyploid.

Autopolyploidy

multiple chromosomes from one’s own species.

Allopolyploid

occurs when gametes from two different species combine.

Example of Allopolyploid?

wheat, cotton and tabaco.

Where is Allopolyploid most common?

In plants.

What did Theodosius Dobzhansky said?

nothing in biology makes sense, except in the light of evolution.

What is Evolution?

Is the change in genetic composition of a population over time, specially over generations.

What is a misconception of evolution?

Evolution explains life’s origin,

The theory of Evolution

Explains how populations change overtime and how life diversifies the origin of species.

Divergent Evolution

an evolution that results in different forms in two species with a common ancestor.

Gene Pool

all the alleles carried by all the individuals in the population.