LO topic 6a Flashcards
Define the terms ‘population’, ‘community’, ‘ecosystem’ and ‘biosphere’;
Population - the total group of a specific species from a particular area
Community - the group of interacting species with an area
Ecosystem - the community and all the nonliving components of the area
Biosphere - the whole ecosystem that describes the entire planet. (lithosphere and atmosphere)
List the four major factors that determine population growth
Natural increases occur when the difference between birth and death is greater.
Birth
Death
Net migration (immigration and emigration) (in and out)
Define exponential growth, logistic growth,
Logistic growth - S shaped population curve when new populations stabilise as a result from environmental resistance these resistance could either biotic (living like prey/predator population) or abiotic (environmental like weather, temperature)
Exponential growth - growth which as the point of recording has a growing offspring population than deaths this will produce a j shape on a graph. This often happens when there is an increase of food or invasive species have no natural predators.
Define boom-and-bust cycles and carrying capacity
Boom and bust cycles - when a population size rapidly grows until the carrying capacity is reached, which then the population will rapidly decile, creates a curve on tha population graph.
Carrying capacity - the capacity of which the ecosystem has to hold a population before stuffing damage. If the carrying capacity is exceeded this can risk perinatal decreasing the carrying capacity.
Define density-independent and density-dependent mortality factors, and describe population fluctuations that occur between populations of a predator and its prey
density-independent - limit population size regardless of the population density (weather)
density-dependent - control population as pressure increase as population increase (predation and interspecific and intraspecific competition)
population fluctuations - as the predator population grows the prey population decreases, and vice versa if these populations are in control they will interact to naturally control each other and prevent population exponential growth.
Define the terms ‘co-evolution’, ‘ecological niche’
Coevolution - when two or more species reciprocally affect each other evolution as a ct as agents of natural selection. Consider predators killing the weaker population and the phenotype and genotypes become rarer for those species, the predator then adapts to hunt to more difficult species populations.
Ecological niche - when the species occupies a specific habitat for reproduction and survival, these can be broad or narrow. The role refers to how the species engages with the community in the ecosystem.
Define ‘competition’
Competition - interaction between species in which both are harmed. Includes intraspecific (same specifics share the same resource) interspecies (multiple species share the same limited resources).
Describe how resource partitioning helps to reduce interspecific competition; and describe the role of intraspecific competition in limiting population growth.
(Intraspecific) When species develop a pattern of resource usage that is not competitive, consider how this narrows that ecological niche, however it reduces competition, later this population may split into different species.
(Interspecific) one of the species may be out-resourced and go extinct or develop an uneasy alliance with the competitor.
Intraspecific competition - most intense form of competition is between the same species, this exerted density dependent environmental resistance and greatly limits population size.
Define the following types of interactions between species: predation, parasitism, and mutualism.
Predation - the relationships between predator and prey entails where one benefits and the other is harmed.
Parasitism - a relationships which one benefits from the detriment from another species
Mutualism - a type of symbiosis in which both species benefits
Describe the major difference between the way energy and nutrients move through ecosystems;
Category of feeding or ‘trophic level’ determines the method of energy flow with 1 - self feeders or 2 - other feeders.
Define the following terms that relate to energy flow through communities: trophic level, producers, primary consumers, secondary consumers, net primary production.
Trophic levels - energy flow through ecosystems (level 1 - autotrophs) (level 2 - heterotrophs)
Producers - amount of life support is determined by the energy captured by the producers (species)
Primary consumers - feed directly on producers (herbivores)
Secondary consumers - feed on herbivores (carnivores)
Net primary production - carnivorous feed on other carnivores
define food chain and food web
Food chain - linear feeding relationship which includes a single species for each trophic level
Food web - shows many interconnected food chains and more accurately describes the feeding relationships in the community.
define detritus feeders and decomposers;
Detritus feeders - mostly small unnoticed organisms, such as earthworms, millipedes and beetles.
Decomposers - Organisms which break down organic material (fungi, bacteria)
define energy pyramid, biomass, and biomagnification.
Energy pyramid - show energy relationships between the trophic level getting higher as it narrows.
Biomass - the amount of living matter in a unit area of volume of habitat
Biomagnification - organisms many consume or hold toxic substances that are stored in the predator when consumed, this continues up the trophic level gaining concentration ‘magnifying’
