LIFE 320 FINAL

• Ecosystems include both biotic and abiotic components. Ecosystems are a part of the biosphere and have some sort of physical environment.
• Leaching is the process where groundwater removes some nutrients/substances from soil.
• Weathering is the physical and chemical alteration of rock materials. Water can dissolve soluble material and replaces some elements with hydrogen creating clay.
• Liebig's Law of the Minimum states that while many factors exist and affect ecosystem productivity, there can be a single one that limits the overall productivity regardless of these other factors.
• Biotic components include producers, consumers, & decomposers.
• A species is defined as a group of individuals that survive, reproduce together, and don't breed with other species.
• The 4 laws of ecology

  1. everything is connected to everything else
  2. everything must go somewhere
  3. nature knows best
  4. no such thing as a free lunch
• A biome is defined as a major ecological community that extends over a large area and is generally characterized by dominant vegetation.
• Properties of Air

  • Adiabatic cooling: cooling effect of reduced pressure on air as it rises
  • Latent heat release: amount of energy required for phase change
  • Adiabatic heating: heating effect of increased pressure on air as it sinks
  • Albedo: the fraction of solar energy reflected by an object
• The Coriolis Effect


  Because of Earth's curvature, areas on the equator move faster than areas at the poles.
• Gyres are a large system of rotating ocean currents. Warm water is moved along the eastern coasts of continents from the equator and cooler water is moved from the poles towards the western coasts.
• Rain shadows

  • increased energy = increased vaporization + air moisture
  • cool air --> condensation
  • warm air --> evaporation
• Lamarckian view of evolution states that frequent use of a trait allowed for the transformation/evolution of species but was proved to be wrong by Darwin & natural selection.
• Reproductive isolation supports & drives speciation. This can be due to geographical/habitat differences, behavioral/mechanical differences, temporal differences, or incompatibility of gametes/genetics.
• Types of Selection

  1. Directional --> 1 extreme phenotype is favored
  2. Disruptive --> Both extreme phenotypes are favored
  3. Stabilizing --> Intermediate phenotypes are favored
• Types of Speciation

  1. Allopatric --> geographic isolation
  2. Parapatric --> behavioral or genetic isolation
  3. Peripatric --> habitat isolation (drift, founder effect, bottlenecking)
  4. Sympatric --> within a shared area/habitat, genetically isolated
• Adaptive radiation is the diversification of an ancestral group to fill several habitats/niches. This creates new species (ex. Darwin's finches).
• Islands closer to the mainland have more species diversity. Islands larger in size also have an increased number of species. Smaller islands have higher extinction rates, but if colonization rates are greater than extinction rates, the overall number of species increases.
• Adaptations are traits of an organism that allows them to maximize their fitness. Adaptations can be structural/physical, chemical, behavioral, or appearance-based.
• R-selected species have a short time to maturity, short life spans, large numbers of offspring, and less parental investment.
• K-selected species have long times to maturity, longer life spans, fewer offspring, and more parental investment.
• Precocial species are less reliant on parents and can feed themselves almost immediately after birth. Altricial species depend on their parents for food after birth.
• Semelparity means an organism will reproduce once throughout its lifespan (common in insects & plants). Iteroparity means an organism reproduces multiple times in its lifespan (common among mammals, birds/reptiles).
• Senescence is the gradual decrease in an organism's fecundity and increase in probability of mortality.
• A niche is a range of physical & biological conditions in which a species lives, this also accounts for ways they obtain things for survival & reproduction. A habitat is simply the physical environment in which a species lives.
• Competition can be intraspecific (between members of the same species) or interspecific (between members of different species)
• An organism's fundamental niche is defined by the organism's physiology whereas their realized niche is the niche the organism actually occupies given constraints.
• Mesopredators are relatively small carnivores that prey on herbivores. Top/apex predators are at the top of the food chain, consuming other predators & herbivores.
• Lotka-Volterra Model models predator/prey interactions & oscillations their respective populations.

  $dN/dT=$$rN-cNP$

  dN/dT --> change in prey population/change in time

  r --> rate of population growth

  N --> # prey

  c --> probability of prey death/capture

  P --> # predators

  (cNP --> rate of individuals killed/captured by predators)
• Functional response


  relationship between density of prey and an individual predator's rate of food consumption
• Types of Functional Responses

  1. Type I: pred/prey increases in linear fashion until satiation
  2. Type II: rate of consumption begins slow as prey increase then plateaus
  3. Type III: low, rapid rate of prey consumption when prey density is low (opposite when density is high)
• Search image


  A learned, mental image that helps predators locate & capture prey
• Defense Mechanisms

  • behavioral (alarm calling, reduced activity, etc.)
  • crypsis (camouflages)
  • structural (spines, quills, etc.)
  • chemical (toxins, ink, sprays, etc.)
  • mimicry (palatable, looks like poisonous = Batesian, poisonous, looks like palatable = Mullerian)
• Pioneer species occupy newly disturbed lands, generally these are r-selected and have increased tolerance.
• Climax communities are stable communities that don't undergo further succession.
• Primary succession is the process that follows the removal of soil and or formation of new land (lava flows, glaciers, etc.). Secondary succession is the process that follows a disturbance without soil removal or land formation.
• Eutrophication occurs when a body of water has increased nutrient concentration which results in reduced biodiversity and oxygen levels.
• Intermediate Disturbance Hypothesis


  At times of low disturbance, the most competitive species dominates, at times of high disturbance, no species can build a dominating population, and at times of intermediate disturbance, the most competitive species are kept in check and the less competitive increase in population size.
• Endemic species live in a single, isolated location. Cosmopolitan species have large, broad home ranges.
• Types of Dispersion

  • Clustered: individuals in aggregated groups
  • Evenly-Spaced: individuals maintain uniform distance between self & neighbors
  • Random: position of individuals is independent of that of others