Biology I Final Notes

Biology I Final Exam Flashcards

Genetics

The study of genes and genotypes in a population.

Population

Group of individuals of the same species interacting with each other and the abiotic environment within a given area.

Gene Pool

All of the alleles for every gene in a population.

Hardy-Weinberg Theorem

Describes a non-evolving population.

Allele Frequencies

p + q = 1, where p is the frequency of the dominant allele and q is the frequency of the recessive allele.

Genotype Frequencies

p² + 2pq + q² = 1, where p² is the frequency of AA, 2pq is the frequency of Aa, and q² is the frequency of aa.

Five Conditions for Hardy-Weinberg Theorem

No mutations, isolation from other populations, random mating, large population size, and no natural selection.

Sources of Genetic Variation

Mutation, horizontal gene transfer, and sexual recombination.

Mutation

Ultimate source of variation, but usually does not change allele frequency due to rare occurrence.

Gene Flow

Populations exchange members or gametes, heavily involved in change.

Nonrandom Mating

Inbreeding is the most common form; does not alter allele frequency but changes the proportion of heterozygotes.

Genetic Drift

Statistical accidents; random fluctuation in allele frequencies increases as population size decreases.

Selection

Only agent that produces adaptive evolutionary changes.

Directional Selection

One extreme of a phenotypic distribution is favored.

Stabilizing Selection

Individuals with an intermediate phenotype have higher fitness.

Diversifying/Disruptive Selection

Two or more phenotypes have high fitness.

Balancing Selection

Maintains a balanced polymorphism in a population via heterozygous advantage and negative frequency-dependent selection.

Sexual Selection

Some individuals along a phenotypic distribution are more successful at attracting mates and, therefore, have higher fitness.

Genetic Drift

Changes in allele frequencies due to chance; alleles can be eliminated or fixed.

Bottleneck Effect

Drastic reduction in population size.

Founder Effect

A few individuals from a population start a new population with a different allele frequency than the original population.

Three Domains of Biodiversity

Bacteria, Archaea, and Eukarya.

Jean Baptiste Lamarck

First model of evolution (1809), inheritance of acquired characteristics

Charles Darwin

Naturalist with an empirical approach and developed the second model of evolution, natural selection

Evolution

Changes over time.

Evidence of Biological Evolution

Studies of natural selection, selective breeding, biogeography, convergent evolution, fossil record, and homologies

Horizontal Gene Transfer

Crossing over of genes during phagocytosis

Classification of Species

Domain, Kingdom, Phylum, Class, Subphylum, Order, Family, Sub Family, Genus, Species

Biological Species Concept

Individuals of the same species can interbreed and produce viable, fertile offspring.

Evolutionary Lineage Concept

Series of species in a line of descent where each new species evolved from the immediate, previous ancestor.

Ecological Species Concept

Each species occupies an ecological niche.

General Lineage Concept

Each species is a population of an independently evolving lineage.

Speciation

Occurs when one ancestral species evolves into one or more new species.

Gradualism

Change occurs gradually over a long period of time.

Punctuated Equilibrium

Periods of stasis interrupted by occasional bursts of speciation.

Allopatric Speciation

Arises by geographic isolation of a few members of the original population or species.

Hybrid Zones

Areas where separated populations interbreed.

Sympatric Speciation

Often arises by instantaneous speciation through polyploidy, or having one or more additional sets of chromosomes.

Behavioral Isolation

Members of a species often identify each other through specific rituals.

Temporal Isolation

Many species reproduce only at specific times.

Habitat Isolation

If species live in slightly different habitats, they may never meet.

Mechanical Isolation

Members of different species often cannot mate because their anatomies are incomplete.

Gametic Isolation

The gametes (sperm and egg) of different species usually cannot fertilize each other.

Hybrid Inviability

The fertilized egg fails to develop.

Hybrid Sterility

An interspecies hybrid survives, but it is sterile.

Hybrid Breakdown

The F1 interspecies hybrid is viable and fertile but succeeding generations (F2 and so on) become increasingly inviable.

The Biological Species Concept applies to

Sexually reproducing species, living species, species with gene flow between populations

The Biological Species Concept cannot be applied to

Species that reproduce asexually, extinct organisms, limited gene flow between populations

The Environment

The selective pressure of natural selection.

Climate

Large spatial and temporal scale.

Microclimate

Small spatial and temporal scale.

Ecology

The scientific study of the relationships and interactions between organisms and their environment.

Environmentalism

A broad philosophy and social movement that seeks to maintain environmental quality and justice.

Five Comprehensible Levels of Ecology

Organismal, Population, Community, Ecosystem, and Global.

Organismal Ecology

Focuses on the ways that species adapt to their environments over time through physiology and behavior.

Population Ecology

Is concerned with the factors that affect population size, growth, and density.

Community Ecology

Focuses on interactions among species.

Ecosystem Ecology

Concerned with questions of energy flow and chemical cycling.

Global Ecology

The study of the influence of energy and matter on organisms across the biosphere.

Biotic Factors

The living organisms of an ecosystem.

Abiotic Factors

The non-living components of an ecosystem.

Tundra

Long, very cold winters and permafrost frozen soil.

Boreal Forests / Taiga (Coniferous Forests)

Largest land biome on Earth, long cold winters and short wet summers, coniferous trees dominate, thin acidic nutrient-poor soils

Temperate Deciduous Forest

Wide range of seasonal temperatures, deciduous trees dominate, relatively nutrient-rich soils

Tropical Forests

Temperature "summer" year-round, precipitation can vary, high biodiversity, nutrient poor acidic soils

Temperate Grasslands

Treeless, hot dry summers and cold winters, tallgrass mixed-grass and short grass prairies, historically deep, nutrient-rich soils

Chaparral

Mediterranean climate, spiny shrubs dominate, fire-dependent vegetation, fragile soils prone to mudslides

Deserts

Very hot and dry, succulent cacti and spiny shrubs

Rachel Carson

Wrote Silent Spring in 1962 and demonstrated that humans were a part of the environment, not in control of, or separate from it.

Causes of Species Endangerment (HIPPCO)

Habitat Destruction, Invasive Species, Population Growth (Human), Pollution, Climate Change, and Over harvesting

Weather

Ehort term changes that occur in, and controlled by, the composition and behavior of the troposphere

Climate

Long term weather patterns also controlled by the composition and behavior of the troposphere

Greenhouse Gasses

Carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, and water vapor.

Biomagnification

The tendency of certain chemical pollutants to concentrate in higher trophic levels in food chains.

Invasive Species

Species that have been introduced into new geographic areas by people and spread/outcompete native species without human assistance

Biodiversity encompasses

Genetic diversity of a species, variety of species in an area, variety of ecosystems on a landscape

Biophilia

"Love of Life"; human desire to affiliate with other life in its many forms

Conservation Biology

Branch of ecology that seeks to investigate and reverse the loss of biodiversity.

Restoration Ecology

Uses ecological principles to help repair degraded areas.

Biodiversity Hot Spots

Relatively small areas with unusually high concentrations of endemic species and endangered species.

Fragmentation

The splitting of habitats that causes populations to become isolated from one another

Bioremediation

The use of living organisms to detoxify polluted ecosystems