Community Flashcards
Define ‘community’.
Refers to a group of plant and animal populations that live in a particular area at a particular time and interact with each other.
How does a population differ from a community?
A population consists of only one type of species.
What are possible types of interactions in a community?
Competition
Predation
Herbivory
Symbiosis
What are the 4 types of symbiotic relationship?
Amensalism
Commensalism
Parasitism
Mutualism
Explain the interaction competition and provide an example.
The interaction that occurs when individuals of different species compete for same resources which is limited in supply. Both are negatively affected as this limits the growth and survival of organisms involved.
Example, Red ants and black ants both opting for the same food, and ending up competing with each other to obtain it. This will negatively impact both ants.
Define ‘niche’.
Is the ecological role a species play in its ecosystem. It refers to everything about its life, particularly its relationship with other organisms with its physical surroundings (both biotic and abiotic)
What are the ecological niche’s of an earthworm?
Burrowing through the soil eating organic matter. They prefer moist, dark habitat, birds are their main predators. They produce sexually, with internal fertilisation, each individual having both male and female sexual organs.
How is niche overlap between species reduced?
Division of resources, which is favoured by natural selection.
What does resource division do?
It reduces competition, allowing greater population size and diversity in communities.
Explain the interaction ‘predation’ and provide an example.
Is the interaction between species in which the predator kills and eats the prey In this interaction, the predator benefits and the prey is negatively affected.
Example, mongoose killing and eating a chicken.
Explain the interaction ‘predation’ and provide an example.
Is the interaction between species in which the predator kills and eats the prey In this interaction, the predator benefits and the prey is negatively affected.
Example, mongoose killing and eating a chicken.
Explain the interaction ‘herbivory’ and provide an example.
Is the interaction where an organism eats a part of the plant or algae In this, the herbivore benefits and the plant is negatively affected.
Example, a cow eating grass, the cow benefits by getting food and the plant is negatively affected as it loses its greens and photosynthesis will be affected.
Explain the term ‘symbiosis’ .
Symbiosis is the relationship when individuals of two or more species live together in direct contact with one another.
Explain the symbiotic relationship, Amensalism and give an example.
Is a relationship where one organism is harmed, the other one remains unaffected.
Example, an algal bloom in the river causes death to many aquatic animals but the algae remains unaffected.
Explain the symbiotic relationship, Amensalism and give an example.
Is a relationship where one organism is harmed, the other one remains unaffected.
Example, an algal bloom in the river causes death to many aquatic animals but the algae remains unaffected.
Explain the symbiotic relationship, Parasitism and give an example.
Is the relationship where the parasite benefits and the host is harmed.
Example, mosquitos, they benefit by obtaining food (sucking blood) while the host is harmed because it causes redness and itchiness.
Define ‘zonation’.
Is the division of organisms into areas or zones, of varying environmental factors.
Differentiate between zonation and stratification.
Zonation is the horizontal environmental division (side by side) whereas stratification is the vertical environmental division.
Explain an example of zonation.
The stream ecosystem has roughly 3 zones; wet zone, damp zone and dry zone. Different organisms are adapted to different zone conditions. Algae will be found in the wet zone, mosses and ferns in the damp zone, and herbaceous plants in the dry zone.
Explain ‘stratification’.
Is the vertical layers of organism in communities. Each layer is known as a stratum and different organisms live in the various strata depending on their living requirements.
Explain an example of stratification.
The rainforest. The top layer is known as the canopy with the most amount of sunlight and wind but with the least amount of humidity. The middle layer is known as the understory, receiving less sunlight and wind compared to the compared to the canopy, but have higher humidity. The bottom layer is known as the forest floor, with the highest humidity but with lowest amount of sunlight and wind.
How does stratification reduce competition?
- it divides the organisms into separate areas, like zonation.
- The many strata create a large number of varied habitats, greatly increasing the diversity and number of organisms the ecosystem can support.
Define ‘succession’.
Is the orderly progression of species composition in an empty area of land, from colonizing pioneer species to a stable community.
Briefly describe the several stages that occur in succession.
- A new habitat is formed with no form of life, example, an island created by a volcanic eruption.
-Pioneer species colonize the newly available habitat. - Once the pioneers sheltered the soil, the seeds of perennial plants take root. Overtime perennials crowd out the original pioneer species.
- Finally, after several stages of successive groups of organisms, the environmental conditions stabilize and the community reaches a stable composition of species called the climax community.
