Ecosystems and Material Cycles Flashcards
What is an organism?
A single living individual
What is a population?
All the organisms of the same species in an area
What is a community?
All the populations in an area
What is an ecosystem?
The community and the non-living components in an area, all organisms in an ecosytem depend on other organisms for food, shelter etc.
What factors effect distribution of living organisms?
- Biotic factors (factors that involve living organisms) such as prey, competitors and predators
- Abiotic factors (non-living factors) such as light, average temperature, average rainfall, oxygen levels in water, pollution
How can changes in abiotic factors be measured?
Using equipment such as a thermometer, oxygen meter etc.
What is a pollutant?
Energy or a chemical substance that has a harmful effect on living organisms
How do organisms deter predators?
- Some animals show that they’re highly poisonous by displaying very bright colours
- Some animals have frightening colours and patterns on them
- Some plants have big thorns and other plants are poisonous
Why is there competition between organisms?
Organisms need a supply of materials from their surroundings and sometimes from other living organisms, some materials have limited supply, therefore there is competition between organisms
What kind of competition is there between plants?
Competition for light and space above ground, competition for water and nutrients underground
What kind of competition is there between animals?
- Food
- Mates for reproduction
- Territory (space for feeding, reproduction etc)
What is parasitism?
Where a parasite feeds of a host when they’re living together, this harms the host but benefits the parasite
Give some examples of parasites
- Fleas, they feed off other animals by sucking the animal’s blood after piercing its skin
- Head lice, they feed off humans by sucking blood off a human head after piercing the skin
- Tapeworms, they feed off other animals by living in the animal’s intestine and absorbing nutrients from the digested food in the intestine
- Mistletoe, mistletoe grows roots into a tree to absorb water and nutrients from the host
What is mutualism?
When two organisms live closely together in a way that benefits them both
Give some examples of mutualists
- Oxpeckers and herbivores such as deers, the bird benefits by getting food, the herbivore benefits from the loss of skin parasites
- Larger fish such as a sharks and cleaner fish, the larger fish benefits from the loss of dead skin and parasites, the cleaner fish benefit by getting food
- Nitrogen fixing bacteria and legume plant, the nitrogen fixing bacteria benefits as it is protected from the environment and gets food from the plant, the legume plant benefits by getting nitrogen compounds for healthy growth from the bacteria
How does sampling with quadrats work?
- Quadrats are placed randomly in the area
- The number of study organisms are counted in each area
- The number of organisms in the whole area is estimated using the equation: number of organisms in the whole area = mean number of organisms in one quadrat x (total area / area of one quadrat)
What is a belt transect?
A transect line (for example, a tape measure) is placed along the ground, then quadrats are placed at regular intervals along the transect, belt transects are used to observe the effect of abiotic and biotic factors on the distribution of an organism. The changes in factors are also measured at each quadrat position, this makes it easier to link a change in distribution with a physical factor
Give some examples of when belt transects would be used
- When there is a pond nearby to dry land
- When there’s a low tide on a rocky shore near to high tide
How do trophic levels work?
- Energy is transferred to a plant by light during photosynthesis, most of that energy is stored in new plant biomass which can be transferred to herbivores in their food, however, some of the energy is transferred to surroundings as heat because of respiration
- When this plant is eaten the biomass is transferred and stored as animal biomass, they have energy that is transferred to the surroundings as heat by respiration as well, they also have energy stored in faeces and urine
What are apex predators?
Carnivores with no predators