2 Flashcards
Species
A group of organisms that share similar characteristics and are capable of interbreeding to produce fertile offspring.
Population
A group of organisms of the same species living in the same area at the same time.
Habitat
The environment which a species normally lives in.
Abiotic Factors
The non-living physical factors which influence the organisms and ecosystems. Temperature, salinity, mineral content, dissolved oxygen, availability of freshwater.
Biotic Factors
The different species in an ecosystem and the interactions between them.
Niche
The particular set of abiotic factors and biotic conditions and resources to which an organism or population responds.
Fundamental VS Realised Niche
Fundamental - where and how an organism COULD live (due to Abiotic factors).
Realised - Where and organism DOES live (due to biotic factors).
Competition
Organisms competing for resources.
Intraspecific Competition
Competition between members of the same species.
Interspecific Competition
Competition between members of different species.
Parasitism
An organism, the parasite, benefits off a host who suffers. A Tick.
Mutualism
Two species interact and both benefit.
Disease
Causes sickness. Caused by pathogens, bacteria, viruses, fungi, and single celled animals (protozoa).
Predation
When animal, or plant, eats another.
Commensalism
One species benefits and the other neither benefits nor suffers.
Herbivory
Organism feeds on plant matter.
Carrying Capacity
The maximum number of a species that can be sustainably supported by the environment.
Limiting Factors
Restrict the growth of a population or prevent it from increasing. Factors which slow down growth of a population as it reaches its carrying capacity.
Community
A group of populations living an interacting with each other in a common habitat.
Ecosystem
A community and the physical environment it interacts with.
Respiration
The process of breaking down food to get energy in order to complete living processes.
Photosynthesis
The process by which green plants make their own food from water and CO2 using energy from the sun.
Compensation Point
The point at which a plant is neither using energy to increase in biomass or using it to stay alive.
Food Chain
The flow of energy from one organism to the next, showing the feeding relationships between species in an ecosystem.
Trophic Level
The position that an organism or community of organisms occupy in food chains.
Producers
Autotrophs and Chemosynthetic Organisms - make their own enegry.
Consumers
Heterotrophs - get energy from feeding on autotrophs.
Decomposers
Obtain energy from dead organisms
Detritivores
Obtain energy from detritus or decomposing organic material
Omnivores
Eats both plants and animals.
Food Web
Shows the complex nature of the feeding relationships between organisms in an ecosystem.
Productivity
The conversion of energy into biomass over a given time period. Mass per unit volume per unit time. Kg V^-1 Years^-1
GP
The total gain in energy or biomass per unit time.
NP
The gain in energy or biomass per unit time after deductions.
NPP
NPP=GGP-R
GSP
GSP=Food Eaten-Fecal Losses
NSP
NSP=GSP-R
Biome
A collection of ecosystems that share similar climatic conditions.
Climate Change Effects on Biomes
Biomes move more north/south. Fauna on mountainous are stuck.
Tricellular Model
Hadley then Ferrel then Polar Cells. LP at equator, 0 degrees, between Hadley cells. High P. HP at 30 degrees, between Hadley and Ferrel cells, P is low. Low pressure at 60 degrees, between Ferrel and Polar cells, P is high.
Zonation
The change in a community along an environmental gradient due to factors such as changes in altitude, latitude, tidal level or distance from shore/coverage by water.
Primary Succession
No ecological resources available to trigger the process of succession. No organic matter and no soil.
Secondary Succession
Any form of ecological resources are present to start the process of succession. Bacteria, seeds, moss, lichen.
Stages of Succession
Bare surface. Colonisation (organic matter bought to area of land). Establishment (Species diversity and soils develop). Competition (K-strategists begin to outcompete R-strategists). Stabilisation (Environment establishes itself, complex food webs, narrow niched, few new species). Climax community (Stable and self-perpetuating. Species diversity decreases). CECSC.
R-Strategists
Species which:
-Spread reproductive investments over large numbers of offspring
-Short life-spans
-Early maturity
-Little parental care
-Pioneers, colonisers
-Lower trophic level
K-Strategists
Species which:
-Concentrate reproductive investments over few offspring
-Long life-spans
-Late maturity
-High parental care
-Later stages of succession
-Higher trophic level
Disturbance
A change in environmental conditions cause change in an ecosystem, leaving space for new species to develop.
Arrested Succession
Succession stopped/paused in a stage due to a change in an abiotic or biotic factor, soil conditions or overgrazing. Succession will continue once the limiting factor is removed.
Deflected Succession
A disturbance may cause a community to be moved to a different stage of succession. This leads to a plagioclimax community, pasture, farmland. Once the disturbance stops, succession can continue.
P to E Ratio
> 1, leaching in soil. =1, soils are rich and fertile. <1, salinisation of soil.
Population Dynamics
The study of the factors that cause changes to population sizes.
What is the trophic efficiency (how much energy is passed on between trophic levels)?
10%
Assimilation Efficiency
GP*100/Food Eaten
Efficiency of Biomass of Productivity
NP*100/GP
Factors Which Affect Biome Distribution
Latitude and Altitude (I and T). Ocean currents and Winds. P/E Ratio. Productivity.
