Evolution
Change in the gene pool of a population/species over time; Primary way for finding new ways to obtain energy
Natural Selection
Mechanism of evolution; Driving force; Can only edit existing variation
Overpopulation
Leads to: Competition, survival of the fittest, increase in beneficial variations
Mutation
Creation of a new variation; Rarely beneficial
Speed of Evolution
Slow and fairly inefficient
Species
Group of individuals that actually or potentially interbreed in nature
Microevolution
Evolution on a small scale within a single population; Observable over few generations; Does not lead to speciation
Macroevolution
Large scale evolutionary changes; Leads to speciation; Occurs over long periods of time
Isolation
Required for new species to evolve
Speciation
When a new species arises when a member of a population becomes isolated for a long period of a time; Become different from ancestors that they are considered new species
Allopatric Speciation
Species evolve from physical or geographic isolation
Sympatric Speciation
New species evolve from a common population while the populations are in the same geographic proximity
Barriers of Isolation
Mechanical (sex organs), temporal (breeding/feeding timing), behavioral (courtship behavior), and ecological (fill different niches)
Adaptive Radiation
Starts with mass extinction; No organisms --> No competition --> More resources --> Other organisms increase --> Increase mutation --> New species
Selective Pressure
An agent of differential mortality or fertility that tends to make a population change genetically; Temperature, moisture, food supply, and predation
Tolerance Limits
Organisms are adapted to certain sets of conditions
Leibig's Law
Single factor in shortest supply is the determinant of a species distribution
Shelford's Law
Minimum and maximum tolerance limits beyond which a particular species cannot survive, thus determining a species distribution
Coevolution
Process in which species exert selective pressure on one another; Organisms react to changes in the environment, as well as changes in other organisms as well
Divergent Evolution
Mutations and different selective pressures cause populations to evolve along dissimilar paths
Homologous Structures
Same structure with a different function
Convergent Evolution
Unrelated organisms evolve separately to cope with environmental changes in the same fashion
Analogous Structures
Same function but a different structure
Vestigal Structure
Anatomical feature that no longer has the purpose in the current form of that organism
Community
All living organisms in a particular area
Community Structure
Combination of a communities physical appearance, species diversity, and ecological roles
Species Diversity
Number of different species it contains combined with the abundance of individuals within each species
Niche Structure
How many potential ecological niches occur, how they resemble or differ, and how the species occupying different niches interact
Geographic Location
Species diversity is highest in the tropics and declines as we move from equator toward the poles
Ecological Complexity
Measure of the number of species at each trophic level and the number of trophic levels in a community
Habitat
Place or set of conditions where an organism lives
Niche
Role played by a species in a biological community
Competitive Exclusion Principle
No two species occupy the same niche
Fundamental Niche
Full potential range of physical, chemical, and biological factors a species can use if there is no competition
Realized Niche
Parts of the fundamental niche of a species that are actually used by that species; Acts to avoid competition
Generalists
Broad niche that utilize only small amounts of any given resource but sample from many different kinds of resources
Specialists
Narrow niche; Can only tolerate narrow range of conditions
Predation
When an organism feeds directly on another living organisms; One benefits and the other is harmed (scavengers, detritivores, decomposers NOT included)
Parasitism
Organisms that feed on host without killing it; One species benefits and the other is harmed
Pathogens
Disease-causing organisms; May or may not kill host
Batesian Mimicry
Unharmful species looks like a harmful one
Mullerian Mimicry
Two harmful species evolve to look like one another
Competition
Antagonistic relationship within a community
Intraspecific Competition
Members of the same species competing against each other
Interspecific Competition
Competition between members of different species
Cooperation
Mutual interaction among species
Chemical Cooperation
Insects
Verbal/Visual Cooperation
Humans
Symbiosis
Living together of two dissimilar species
Commensalism
An interaction between two organisms where one benefits and the other remains neutral
Mutualism
Interaction between species where both benefit
Keystone Species
Help determine the types and numbers of other species in a community thereby helping to sustain it; Not necessarily a lot
Foundation Species
Create and enhance habitats that can benefit other species in a community
Native Species
Those that normally live and thrive in a particular community
Nonnative Species
Those that migrate deliberately or accidentally introduced into a community
Indicator Species
Species that serve as early warnings of damage to a community or an ecosystem
Directional Selection
When evolution favors an extreme
Disruptive Selection
When evolution favors both extremes
Stabilizing Selection
When evolution favors the medium
Inertia
Ability to resist change
Resilience
Ability to bounce back from change