Dat Biology- Evolution

Front 1

Microevolution

Back 1

Describes the details of how populations of organisms change from generation to generation and how new species originate.

Front 2

Macroevolution

Back 2

Describes patterns and changes in group of related species over broad periods of geologic time.

The patterns determine phylogeny, the evolutionary relationships among species and groups of species.

Front 3

Lamarck's Theories of Evolution

Back 3

1. Use and disuse- described how body parts of organisms can develop with increased usage and disappear with decreased usage.

2. Inheritance of acquired characteristics- describes how features body features acquired during the lifetime of an organism could be passed on. (This was incorrect).

3. Natural transformation of species- described how organisms produced offspring with changes, transforming each subsequent generation into a slightly different form toward some ultimate, higher order of complexity. Species did not become extinct. (Incorrect)

Front 4

Evidence for evolution- paleontology

Back 4

Provides fossils that reveal the prehistoric existence of species. As a result, changes in species and the formation of new species can be studied.

Front 5

Evidence for evolution- biogeography

Back 5

Uses geography to describe the distribution of species. This information has revealed that unrelated species in different regions of the world look alike when found in similar environments.

Front 6

Evidence for evolution- embryology

Back 6

Reveals similar stages in development (ontogeny) among related species. The similarities help establish evolutionary relationships (phylogeny). Ex: gill slits are found in fish, chicken, pig, and human embryos.

Front 7

Evidence for evolution- comparative anatomy

Back 7

Describes two kinds of structures that contribute to the identification of evolutionary relationships among species.

Front 8

Homologous structures

Back 8

Body parts that resemble one another in different species because they have evolved from a common ancestor. Homologous structures may look different.

Front 9

Analogous structures

Back 9

Body parts that resemble one another in different species but not because they have evolved from the same common ancestor. Instead, they evolve independently as adaptations to their environment. Ex: the fins of sharks, penguins, and porpoises are analogous as adaptations to swimming.

Front 10

Evidence for evolution- molecular biology

Back 10

Examines the nucleotide and amino acid sequences of DNA and proteins from different species. Closely related species share higher percentages. This data strongly favors evolution of different species through modification of ancestral genetic information.

Front 11

Natural selection

Back 11

The differences in survival and reproduction among individuals in a population as a result of their interactions with the environment.

Some individuals possess alleles that generate traits that enable them to cope more successfully.

Front 12

Arguments for natural selection

Back 12

1. Populations possess an enormous reproductive potential.
2. Population sizes remain stable.
3. Resources are limited.
4. Individuals compete for survival.
5. There is variation among individuals in a population.
6. Much variation is heritable.
7. Only the most fit individuals survive.
8. Evolution occurs as favorable traits accumulate in population.

Front 13

Stabilizing selection

Back 13

Eliminates individuals that have extreme or unused traits.

Front 14

Directional selection

Back 14

Favors traits that are at one extreme of a range of traits while the opposite extreme is selected against. Ex: industrial melanism

Front 15

Disruptive selection

Back 15

Occurs when the environment favors extreme or unusual traits while selecting against the common traits. Ex: Short weeds are common on lawns while tall weeds are common in nature.

Front 16

Sexual selection

Back 16

Differential mating of males in a population. Traits that allow males to increase their mating frequency have a selective advantage.

Front 17

Artificial selection

Back 17

Is a form of directional selection carried out by humans when they sow seeds or breed animals that possess desirable traits.

Front 18

Sources of variation

Back 18

1. Mutations
2. Sexual reproduction (genetic recombination)
3. Diploidy
4. Outbreeding
5. Balanced polymorphism- maintenance of different phenotypes in a population.

Front 19

Heterozygote advantage

Back 19

Occurs when the heterozygous condition bears a greater selective advantage than either homozygous condition. Ex: AS heterozygotes (sickle cell gene) have malaria resistance.

Front 20

Hybrid vigor

Back 20

Describes the superior quality of offspring resulting from crosses between two different inbred strains of plants. There is an increase in loci with heterozygote advantage.

Front 21

Frequency dependent selection

Back 21

Occurs when the least common phenotypes have a selective advantage. Soon, these phenotypes increase in population.

Front 22

Causes of change in allele frequency

Back 22

1. natural selection
2. mutations
3. gene flow
4. genetic drift- random increase or decrease of alleles.
5. non-random mating

Front 23

Hardy-Weinberg equilibrium

Back 23

When the allele frequencies in a population remain constant from generation to generation the population is said to be in genetic equilibrium. *No evolution is occurring.

Front 24

H-W Equilibrium conditions

Back 24

1. All traits are selectively neutral.
2. Mutations do not occur.
3. The population must be isolated from other populations.
4. The population must be large.
5. Mating is random.

Front 25

Species

Back 25

A defined group of individuals capable of interbreeding. Speciation is the formation of new species.

Front 26

Allopatric speciation

Back 26

Occurs when a population is divided by a geographic barrier so that interbreeding between the two resulting populations is prevented.

Front 27

Sympatric speciation

Back 27

The formation of new species without the presence of a geographic barrier.
1. Balanced polymorphism (color barriers prevent species of different colors from mating)
2. Polyploidy
3. Hybridization

Front 28

Adaptive radiation

Back 28

The relatively rapid evolution of many species from a single ancestor. It occurs when the ancestral species is introduced to an area where diverse geographic or ecological conditions are available for colonization. (ex: Marsupials of Australia)

Front 29

Maintaining Reproductive Isolation

Back 29

Prezygotic isolation
1. Habitat isolation
2. Temporal isolation
3. Behavioral isolation
4. Mechanical isolation
5. Gametic isolation

Postzygotic isolation
6. Hybrid inviability
7. Hybrid sterility
8. Hybrid breakdown

Front 30

Divergent evolution

Back 30

Describes two or more species that originate from a common ancestor and become increasingly different over time.

Front 31

Convergent evolution

Back 31

Describes two unrelated species that share similar traits.The similarities arise because each species has independently adapted to similar ecological conditions or lifestyles. *Analogous traits

Front 32

Parallel evolution

Back 32

Describes two related species or two related lineages that have made similar evolutionary changes after their divergence from a common ancestor. Ex: Placental and marsupial mammals

Front 33

Coevolution

Back 33

The evolution of one species in response to new adaptations that appear in another species. Ex: occurs between predator and prey, pathogens and immune systems etc

Front 34

Macroevolution

Back 34

Describes patterns of evolution for groups of species over extended periods of time.

1. Phyletic gradualism- argues that evolution occurs by the gradual accumulation of small changes.

2. Punctuated equilibrium- evolutionary history consists of geologically long periods of stasis with little or no evolution interrupted by short periods of rapid evolution.

Front 35

The origin of life

Back 35

1. The earth and atmosphere formed.
2. The primordial seas formed.
3. Complex molecules formed.
4. Polymers and self-replicating molecules formed.
5. Organic molecules were concentrated and isolated into protobionts.
6. Primitive heterotrophic prokaryotes formed.
7. Primitive autotrophic prokaryotse were formed.
8. Oxygen and the ozone layer formed
9. Eukaryotes formed