Eco/Evo Exam 2 Review

Molecular Evolution

Change of DNA sequence and protein composition over time

Microevolution

Change in allele frequency and expression in a population over time

Macroevolution

Formation of a new species over time due to large scale pressures

Species

a group of organisms that produce viable and fertile offspring

Populations

group of organisms from the same species living in the same area/living together

Homologies

• molecular homology

• developmental homology

• anatomical homology

Molecular homology

similar sequences between homologous genes

Developmental homology

similar physiology in utero (human fetus- gill ridges and tail)

Anatomical homology

Structural similarities. Convergent evolution can cause structural similarities due to similar environmental pressures

Convergent Evolution

Two species with different evolutionary lineage that evolve under similar pressures, resulting in similar structural or behavioral features

Natural Selection

evolutionary system in which organisms within a species that are best fit for their environment will reproduce and pass on their beneficial traits, resulting in an increase of those alleles in the population.

Artificial Selection

the change in allele frequency in a population due to human intervention (selective breeding, domestication)

Principles of Darwin

• Geography affects speciation

• modern species arose from previous ones

• natural selection impacts evolution of species

Monomorphic

one allele for the gene in the population

→ highly important molecular function, like ribosomal genes

Polymorphic

2 or more alleles for a gene in a population

→ usually present in the population according to meiotic division

→ 3:1 ratio for standard dominant/recessive alleles

Hardy-Weinberg Equation

1= p² +2pq +q²

Hardy-Weinberg equilibrium

No expected change in alleles– no evolution

Disruptors of Hardy-Weinberg Equilibrium

• Random Mutation

• Natural Selection

• Non random mating

• Genetic drift

• Genetic flow

Nonrandom Mating

Sex traits are selected

• intrasex- members of the same sex compete against each other

• intersex- members of the opposite sex have traits selected by the other sex

Genetic Drift

Random event that changes the allele frequency of the population randomly

• bottleneck

• founder’s effect

• small populations

Genetic flow

The movement of alleles to another pre-existing population.

Theories of speciation

• Biological species concept

• Evolutionary lineage concept

• Ecological species concept

• General lineage concept

Biological species concept

Unique set of traits to survive and produce viable and fertile offspring

Evolutionary species concept

Unique ancestral history from an ancient species lineage

Ecological species concept

each species occupies a specific ecological niche

General lineage concept

each isolated population has the capacity to form its own niche (conglomeration of the other three theories)

Pressures of speciation

• morphological traits

• reproductive isolation

• molecular features

• ecological niche

• evolutionary relationship

Morphological traits

Prezygotic reproductive isolation

• geographical isolation

• temporal isolation

• behavioral isolation

• mechanical isolation

• gametic isolation

Postzygotic reproductive isolation

• hybrid viability

• hybrid fertility

Molecular Features

genome sequencing

Ecological Niche

Species role in an environment

evolutionary relationship

Ancestral lineage

Biogeochemical Cycles

• Carbon

• Oxygen

• Nitrogen

• Water

• Sulfur

• Phosphorous

• Trace Elements

Carbon Cycle

• Biotic

• Primary use: carbohydrates, organic molecules

• Primary source: Atmosphere, and water

• Primary movement across ecosystems: photosynthesis/respiration

Oxygen Cycle

• Biotic

• Primary use: metabolic processes, organic molecules

• Primary source: atmosphere

• Primary movement across ecosystems: photosynthesis/respiration

Water Cycle

• Abiotic

• Primary use: metabolic reactions

• Primary source: w/a/l

  • Primary movement across ecosystems: evaporate, condensate, precipitate

Sulfur Cycle

• Abiotic

• Primary use: proteins

• Primary source: rock

• Primary movement across ecosystems: erosion

Phosphorous Cycle

• Abiotic

• Primary use: nucleic acid, phospholipids

• Primary source: rock

• Primary movement across ecosystems: erosion

Trace Elements Cycle

• Abiotic

• Primary use: metabolic processes

• Primary source: rock

• Primary movement across ecosystems: erosion

Nitrogen Cycle

• Biotic/Abiotic

• Primary use: nucleic acids, proteins

• Primary source: atmosphere

• Primary movement across ecosystems: lightning, bacteria, decomposition

Forest Fire Cyle- Abiotic Factor

Fire provides energy for catabolism

Forest Fire cycle- Biotic factor

Fast (Morell), Medium (Pines), Slow (Fir)

Each provides a conversion of biochemicals into biomolecules