Ecology 37 Flashcards
Population
Group of individuals of the same species, ability to interact and interbreed with each other.
Habitat
Are of temperature, humidity, soil, competitors, predators, etc…
Niche
Functional role in the ecosystem. Total of an organism’s interaction with biotic and abiotic resources of its environment
Ecosystem
All organisms present in a particular are and their physical environment. Biotic and abiotic components.
Community
Group of populations comprised of different species.
Dominant species
a) Possess greater biomass
b) Found in greater numbers
Climax community
Stable community in which populations of animals/plants remain in equilibrium. Succession leads to climax community.
Succession is progressive series of changes.
Primary Succession
New volcanic island, lava flows, glacier retreats, sand dunes. When the terrain was without life.
Lichens and moss usually are first to colonize.
Secondary succession
Series of community changes. An existing community has been cleared out by a disturbance such as a fire. Fast that primary because soil already exists.
Ozone layer
In the stratosphere. Protects us from harmful and damaging effects of UV radiation.
Early earth was a _____ atmosphere
Reducing atmosphere. It containe CH4, NH3, CO2, H2S, and water vapor but no O2.
Cyanobacteria helped through photosynthesis.
Greenhouse gas
CH4, N2O, hydrofluorocarbons, chlorofluorocarbons, CO2, H2O vapor.
Gas in atmosphere that traps heat.
Continental drift
Supercontient Pangaea and was 250 million years ago. Helped explain how fossils in West Africa were the same as those found in South America. The Appalachian mountains in the U.S. fit with the Caledonian Mountains of Scotland.
Tectonic plates.
The mantle of the Earth
Encloses the hot core rich in Fe and Ni. The earth’s crust consists of 47% O2 and 28% silicon.
The air we breath is mostly N2, the earth’s crust is mostly O2.
Lakes and ponds are often classified by their nutrient status.
Oligotrophic: nutrient poor but O2 rich; low productivity of phytoplankton; deep lakes - water is blue or green.
Eutrophic: nutrient rich, lower O2 contentl shallow area; high productivity of phytoplankton; water is green/yellow or brown/green.
Biomes
Large areas of Earth which are characterized by climax community it supports.
Marsh: Wet grassland
Swamp: Wooded wetland
Populations display certain characteristics
a) Size: # of individuals
b) Density: # of individuals per unit area of volume
c) Distribution: pattern of dispersal through its habitat
d) Age structure: pre-reproductive, reproductive, or post reproductive classifications.
Uniform dispersion
Suggests competition among members. Animals that defend their area tend to be uniformly spaced to divide the area between them.
Factors affecting sustainable population
Predation, competition, available resources, pollution, disease
Carrying capacity
of individuals that can be sustained indefinitely by the resources in a given area. Births balanced by deaths.
Population growth rate depends on
Birth rate, death rate, rates of immigration and emigration
Population growth regulation
Density dependent mechanism: decrease birth rate or increase death rate.
When a population grows its density increases and so does competition for resources, predation, wastes, parasitism, and disease.
Density independent factors
Fires, earthquakes, snowstorms, floods
Human populations grow exponentially when
When birth rate remains slightly above the death rate and both rates are constant.
Life history strategies of organisms
r-strategist
High growth rate with many offspring. Little parental supervision, short life spans and waste much energy.
Exponential growth model
Life history strategies of organisms
k-strategist
Low growth rate with few offspring. More stable environment and efficient energy
Logistic growth model
Cohort
Group of same age individuals in a population
Fundamental niche
Theoretical niche in which no limiting factors are present. No competitors, no disease, no parasites, and no predators.
Realized niche
Niche with all interactions.
Symbiosis
Ecological relationship between organisms of different species living in a community.
Commensalism
One organism benefits, the other is neither harmed/helped
Parasitism
One benefits, one harmed
Interspecific competition
Different individuals or a species compete for a resource that limits their growth and survival.
Interference competition
Animals interfere with the same species in competition
Exploitation competition
Both species have equal access to a resource but one exploits it at a faster rate. Indirect harm to the other organisms growth and survival.
Competitive exclusion
A slight advantage will cause one to be eliminated.
If niches are identical, two species will be unable to coexists permanently.
Resource partitioning
E.G. Field with three plants, each plant exploits a different part of the soil.
