Ecology Flashcards
Ecology
Study of the interactions that determine the distribution and abundance of organisms. Considers interactions that occur both biotic and abiotic levels.
Patterns of distribution
Random = equal probability of occurring anywhere. Regular = uniform spacing. Clumped = individuals live in areas of high local abundance separated by areas of low-abundance.
biome
Major life zones. Terrestrial biomes are most often characterised by the main vegetation types. Aquatic biomes are described by their physical environment. Water is important in determining a biome.
Factors that determine abundance and diversity of organisms
Availability of resources such as energy light temperature nutrients and water.
Hopkins law
Air cools as it rises. Hot air can retain moisture.
Coriolis effect
Patterns of deflection taken by objects.not firmly connected to the ground as they travel around the Earth. This deflection is based on earth's rotation and the different speeds and which the planet rotates depending on distance from the equator.
Convection cell
Ascending warm moist air at equator releases rain. Descending dry cold air at 30 degrees North absorbs moisture but does not release it.
Angle of incidence of sunlight
Sunlight strikes the tropics more directly. At higher-latitude sunlight strikes at an oblique angle and that is less effective in heating.
Winds
Trade winds blow from east to west in tropics. Westerlies blow from West to East in the temperate zones.
Rain shadow
Mountains obstructing prevailing winds force air to move up. Air cools it moves up and loses it's water content. Rainshadow forms on the other side with no rain falling in that area.
Primary production
Conversion of energy into chemical energy that is stored in organic compounds in living organisms.
Chemotrophs = obtain the energy to oxidation of inorganic molecules
Phototrophs = use photosynthesis
Radiotrophs = fungi that hypothetically can use ionising radiation as an energy source.
Net primary production
Gross production - cellular respiration.
Trophic levels
The positions an organism occupies in the food chain. Primary producers = plants. Never more than 5 trophic levels because 90% of energy is lost as you move from level to level.
Ecological efficiency
Percentage of energy from a food source that is used for growth and reproduction. Waste is the unassimilated energy. Growth is energy assimilated as biomass or reproduction.
Bioaccumulation
Contaminant levels build up in an individual organism overtime
Biomagnification
Contaminant builds up across food chain levels lowest in primary consumers and highest and quaternary consumers. Example is permafrost buildup of nuclear fallout, lichen and reindeer.
Biodiversity
The variety or variability of life synonym eco system. Also measure a variation at the genetic species and ecosystem level
Niche
What rules an organism fills in their habitat and where
Realised niche
Actual distribution of the organism as limited by interactions with others
Fundamental niche
Possible distribution of the organism as determined by its evolutionary history.
Island equilibrium theory of biogeography
Species diversity on islands will represent a dynamic balance between the probability of successful colonisation by new immigrant species and Extinction of existing residents species.
Small islands have slower rates of immigration and higher rates of Extinction. Large islands have higher rates of immigration and slower rates of Extinction.
Von Humboldt species-area curve
As the area explored increases species richness increases but to a certain point above which increased diversity would strain resources
Specialists
More ecologically efficient but at the cost of having a more restricted fundamental niche when ample resources are available specialist outcompete generalists. Specialists are less resiliant to disturbance.
Generalists
Less ecologically efficient but with a larger fundamental niche. More resilient in the face of disturbance.
Competitive exclusion
A comparative advantage that will eventuate in success for the species and Extinction of the other
Intermediate disturbance hypothesis
Diversity will be highest when disturbance prevents competitive exclusion but is low enough to allow for species to prosper. disturbance may be due to interaction with the environment or other species.
Keystone species
Species with the largest number of interactions with an ecosystem. Had a disproportionate effect on other organisms. Examples include prairie dogs and sugar maple tree.
Red Queen hypothesis
Evolutionary theory that species must constantly adapt evolve and proliferate in order to survive whilst competing against other ever-evolving species. Evolutionary arms race 4 survival. Example gazelles v cheetahs in terms of speed
Symbiosis
Any relationship or interaction between two dissimilar organisms. includes parasitism, competition, predation and herbivory, mutualism commensalism and facilitation
Biodiversity hotspots
Regions characterised by exceptional levels of plant endemism and excessive exceptionally rich in species. 34 on the planet.
Population size parameters
Sources of increase = birth and immigration. sources of decrease = death and emigration
Intrinsic rate of growth
Rate of growth with no extrinsic limiting factors. Constrained only by the species life-history traits. Leads to exponential growth curve.
Exponential growth
Cause when there are unlimited resources and no external limitation. is not sustainable
Logistic growth
Involves a carrying capacity. Population size increases until carrying capacity is reached at which point it will plateau or decrease. Carrying capacity is determined by interactions with the environment and other species.
Life-history traits
Reflect evolutionary adaptations of reproduction strategies and age-specific distribution of reproduction and mortality. Traits include the number of offspring level of investment ages sexual maturity senescence and death
Types of survivorship
Type 1 = mortality accelerates with age for example humans. Type 2 = mostly consistent mortality rate for example squirrels. Type 3 = mortality decelerates over lifespan but starts at high rate for example turtles.
Precocial
Born in advanced state able to feed and move independently almost immediately
Altricial
Born helpless requiring significant parental care to survive
Iteroparity
An organism that's able to have offspring many times over the course of their lives
Semelparity
Life history characterised by death after first reproduction for example major seed crops such as corn wheat and oats or salmon
