unit 4: ecology Flashcards
(19 cards)
ecology
the study of relationships between living organisms and between organisms and their environment.
species
groups of organisms that can potentially interbreed to produce fertile offspring
hybrid
offspring of two different species
population
a group of organisms of the same species who live in the same area at the same time
communities
a group of populations living and interacting with each other in an area
ecosystem
the community of organisms in an area and its interactions with the abiotic factors of the environment
abiotic factors
- non-living
- hydrosphere, atmosphere, lithosphere
- ex) light, heat, minerals, oxygen, humidity
biotic factors
- living
- biosphere
- ex) plants, fungi, protists, animals, bacteria
autotrophs
- self-feeding
- they make their own organic molecules from carbon dioxide substances, such as inorganic substances
- involves photosynthesis:
- take light energy and inorganic substances to obtain chemical energy in the form of organic compounds
- ex) plants, algae, bacteria
heterotrophs
- feed on others
-must obtain organic molecules from other organisms - get their chemical energy from autotrophs or other heterotrophs
- detritvores (ingest organic matter that is living or has been killed)
- ex) dogs, fungi, yeast, humans
heterotrophs: consumers, detritivores, and saprotrophs
consumers:
- heterotrophs that feed on living things by ingestion
- ex) bear
detritivores:
- heterotrophs that obtain organic nutrients from detritus by internal digestion
- eat dead leaves, feces or carcasses
- ex) worms, beetles, woodlice
saprotrophs:
- heterotrophs that obtain organic nutrients from dead organic matter by external digestion
- ex) fungi, bacteria
food chain
a sequence showing the feeding relationships and energy flow between species
food web
a system of interlocking and interdependent food chains
trophic levels
- refer to an organisms position in the food chain
- help classify organisms by their feeding relationships with other organisms of the same ecosystem
- bottom to top
- producers, primary consumer, secondary consumer, tertiary consumer, quaternary consumer
- in order for food chains to work, there must be a large number of producers and fewer members of each subsequent trophic level
energy in ecosystems
- most ecosystems rely on a supply of energy from light energy
- producers such as plants, algae, and cyanobacteria, harness light energy through photosynthesis.
- producers are the most important organisms in any food chain
- without them, the next trophic level would have nothing to eat
(not only do they supply energy, but also intake carbon)
energy conversions
- light energy is converted to chemical energy in carbon compounds by photosynthesis.
- once light energy has been absorbed by the producers, the light energy obtained by photosynthesis is available to the next trophic level
- energy is transferred from one organism to the next when carbs, lipids, or proteins are digested (grass eaten by a cow—> chemical energy transferred to cow
- chemical energy in carbon compounds flows through food by means of feeding
- energy is passed from producers to consumers
- producers use some energy by cell respiration
- energy released in this way is lost to the environment as waste heat
energy loss
- only transferred energy can be used by the next trophic level
- only a small amount of energy which an organism absorbs is converted into chemical energy
- usually only about 10-70% of the energy is used from the previous steps in the food chain
living organisms can convert energy in these ways
- chemical to kinetic (muscle contractions)
- chemical to electrical (nerve cells)
- chemical to heat (cell respiration, making ATP)
- synthesizing large molecules
- active transport of molecules
- muscle contraction
- heat-generating adipose tissue
- energy from these processes is eventually converted into heat
- living organisms cannot convert heat into other forms energy
why not all energy is used
- most energy is lost as heat due to cell respiration at all trophic levels
- some organisms die before being eaten by an organism from the next trophic level
- someparts of an organism