ECOLOGY TERMINOLOGY
•Ecosystem: all the abiotic and biotic factors in an area/environment surrounding a species
•Community: all the organisms present in an area/habitat/ecosystem
•Population: all the individuals of one species in an area
•Environment: sum of all conditions in the ecosystem outside the organism
ECOLOGY TERMINOLOGY
•Habitat: place within an environment in which specific organisms live
•Niche: species function in its habitat, the way the organism uses the abiotic and biotic resources of the environment of the organism to make the most of those opportunities
•Ecological niche – opportunities provided by the habitat and the adaptations
ECOLOGY TERMINOLOGY
•Two species occupy different niches when they DO NOT compete for resources
e.g. Feeding at different times on different organisms
e.g. Notch and window caterpillars feed on different parts of the flax
ECOLOGY TERMINOLOGY
•Two species NO LONGER occupy the same niche when: •one species displaces the other species (better adapted)•one species survives or none survive due to: - competition for abiotic and biotic resources
• Gause’s Principle - no two species with identical ecological niches can co-exist for long in the same place
Abiotic factors – the physical factors in the environment that can act as the stimuli for the organisms’ responses.
Prefixes:
•Light (photo-) - intensity, colour, direction, duration
•Gravity (geo-, gravi- in some texts) - up, down, orientation in space
The Environment
•Temperature (thermo-) - average and range
•Water (hydro-) - humidity, salinity, depth, average rainfall, turbidity, speed of current
•Current (rheo-) - align with current
The Environment
•Chemical (chemo-) - CO2, O2, salinity, pH, pheromones, toxins, inorganic nutrients, Macro/micronutrients
•Touch (thigmo-) - response to solid objects
•Sound – pitch, loudness, range
•Pressure – ocean depths, atmosphere, weather pattern formation
•Wind – velocity, gustiness, direction
•Substrate – composition
•Fire - recycling nutrients, seed germination
Adaptations
Adaptations are features that help an organism to make the most of the opportunities provided by the environment.
Organisms with adaptations more suited to the environment are more likely, through the process of natural selection, to pass on their genes to the next generation.
-Structural – morphological, e.g. colour, appendages
-Physiological – biochemical/metabolic e.g. hormones
-Behavioural – responses to the environment e.g. diurnal, aggression, courtship
-Life History – reproductive strategies for survival
Tolerance
Narrow range of physical factors that makes up the optimal range of tolerance for most organisms. If a factor is to extreme in either direction the organism suffers from physiological stress.
If a factor becomes too extreme (too high/too low) the environmental condition leads to death.
Many animal and plant behaviours are to ensure the organism maintains an optimal condition for survival and ultimately reproduction
Animals must detect and be able to respond to key physical factor changes in their environment
Biotic Factors – all relationships between members of the same species (intraspecific) and with members of other species (interspecific)
Intraspecific relationships:
Competition – for same resources; food, space, light, water, nesting sites, territory, nutrients etc
Reproduction – availability of mates, competition between males, courtship, pair-bond formation, parental care
Aggressive interactions - territories, hierarchies
Co-operative interactions – group formation for defence (prevent predation/grazing), aid survival (hunt in packs)
Biotic Factors –
Interspecific relationships:
Competition – for same resources; food, space, light, water, nesting sites, territory, nutrients etc
Predator / prey relationships
Plant / Animal – grazers, browsers
Succession – replacement of one species by another over time, each species modifying the environment to allow the new species to be established
Stratification – vertical relationships in space with other organisms
Zonation – bands of organisms that form in relation to a gradient in a major environmental factor
Animal / Animal
Plant / Plant
Symbiosis – variety of interactions involving close species contact.
Involves a host and a symbiot.
Mutualism (cooperation) - both species benefit
Commensalism - one species benefits, the other is unaffected
Parasitism (exploitation) - one species benefits, the other is harmed
Competition - neither species benefits
Neutralism - both species are unaffected
Note: endoparasites – live in the host ectoparasites – live on the host
