Topic G: Ecology & the Environment Flashcards
What is a food web?
-A system of interlocking and independent food chains.
Define decomposer?
-An organism whose ecological function involves the recycling of nutrients by performing the natural process of decomposition as it feeds on dead or decaying organisms.
Define producer?
(1) An autotrophic organism capable of producing complex organic compounds from simple inorganic molecules through the process of photosynthesis (using light energy) or through chemosynthesis (using chemical energy).
(2) The first trophic level in a food chain in which it serves as a food source for consumers or for higher trophic levels.
Define primary consumers?
-Any organism that consumes or feeds on autotrophs or decaying matter.
Define secondary consumer?
-A group of organisms that largely feed on primary consumers.
Define adaption?
-The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment.
Define habitat?
-Place where an organism or a biological population normally lives or occurs.
Define population?
-A group of organisms of one species that interbreed and live in the same place at the same time (e.g. deer population).
Define biological community?
-A group of interdependent organisms living and interacting with each other in the same habitat.
Define ecosystem?
A system that includes all living organisms (biotic factors) in an area as well as its physical environment (abiotic factors) functioning together as a unit.
Define biological competition?
-A symbiotic relationship between or among living things for resources, such as food, space, shelter, mate, ecological status, etc. A general rivalry.
Define species?
An individual belonging to a group of organisms (or the entire group itself) having common characteristics and (usually) are capable of mating with one another to produce fertile offspring. Failing that (for example the Liger) It has to be ecologically and recognisably the same.
What are the factors of physical conditions?
These are abotic factors.
- temperature
- light intensity
- water availability
- minerals
- carbon dioxide concentration
- oxygen concentration
- soil type
- relief
What are the biological factors of a habitat?
- These are biotic factors
- the plants and animals that live there and interact with them.
Define a pyramid of numbers?
-This is a diagrammatical representation of the number of different organisms at each trophic level in a ecosystem at any one time.
Define pyramid of Biomass?
-This is a representation of the biomass (amount of mass of each individual) at each trophic level at any one time
Not accurate, they change at different times of year
If inverted the ecosystem is on the verge of collapse.
Pyramids of energy transfer?
-This shows the amount of energy that is transferred from one level to the next.
These are never inverted
Measured in energy/area/time
All energy starts at the sun.
What is a quadant?
-A quadrat is usually a square made of wire. It may contain further wires to mark off smaller areas inside, such as 5 x 5 or 10 x 10 squares. The organisms underneath, usually plants, can be identified and counted.
Quadrats may also be used for slow-moving animals such as slugs and snails.
How is energy transferred through a food chain?
-All energy starts at the sun.
Energy is lost at each level because of excretion and using energy etc… Only 10% on energy gets from one tropic level to the next.
What should you do when using a quadrat?
- It should be placed randomly so that a representative sample is taken.
- The validity and reproductibility of the results increases as the results from more quadrats are analysed.
What is capture, recapture with quadrats?
-One way to estimate the population size of an animal species is capture-recapture. Some animals are trapped, for example, using pitfall traps. They are marked in some harmless way then released. Traps are used a few days later. The numbers of marked and unmarked animals caught in the traps are recorded. The population size is estimated using this formula:
Population size =
Number in first sample times number in second sample over number in second sample previously marked.
When using capture-recapture data, you have to make assumptions including?
- There is no death, immigration or emigration.
- The sampling methods used are identical.
- The marking has not affected the survival rate of the animals.
Define the water cycle?
-The cycle of evaporation and condensation that controls the distribution of the earth’s water as it evaporates from bodies of water, condenses, precipitates, and returns to those bodies of water. Also called hydrologic cycle.
Define the Nitrogen cycle?
-The circulation of nitrogen; nitrates from the soil are absorbed by plants which are eaten by animals that die and decay returning the nitrogen back to the soil.The environmental circulation of nitrogen, which passes through the food chain, the soil and the open air environment.
Define the carbon cycle?
The circulation of carbon atoms in the biosphere as a result of photosynthetic conversion of carbon dioxide into complex organic compounds by plants, which are consumed by other organisms: the carbon returns to the atmosphere in the form of carbon dioxide. Carbon dioxide is also released in combustion and also from the bacteria that help with decomposition.
Define polluted air?
-This contains lots of carbon dioxide, nitrous oxides and CFCs. These greenhouse gasses let heat through from the sun. The warmed earth gives off heat which is radiated back to the earth by the layer of greenhouses.
What are the green house effects?
-Earths temp rising Ice caps are melting Sea levels rising Lowland areas face flooding.
Global warming what is happening?
-Gradual increase of temperature across the world, Global warming is accelerated by humans.
How does it work?
-Refer to global warming presentation.
