Ecologists study environments at different levels of organization. Ecology is the study of the interactions among living things, and between living things and their surroundings.
An organism is an individual living thing, such as an alligator. Organism Organism
A population is a group of the same species that lives in one area. Organism Population Population Organism
A community is a group of different species that live together in one area. Community Community Organism Population Population Organism
Producers provide energy for other organisms in an ecosystem. Producers are also called autotrophs because they make their own food. Photosynthesis in most producers uses sunlight as an energy source. Chemosynthesis in prokaryote producers uses chemicals as an energy source.
Producers provide energy for other organisms in an ecosystem. primary productivity the rate at which solar energy is converted into organic compounds (kcal/m 2 /year) through photosynthesis gross primary productivity total amount of energy produced, including the energy used by the plants for their own cellular respiration net primary productivity rate at which plants store energy that is not used in plant respiration; material that is actually available as food for consumers
Consumers are also called heterotrophs because they feed off of different things. Herbivores eat only plants. Carnivores eat only animals. Omnivores eat both plants and animals. Detrivores (scavengers) eat dead organic matter. Decomposers are detritivores that break down organic matter into simpler compounds.
Trophic levels are the feeding levels which shows how energy flows in an ecosystem. (carnivores) (carnivores) (herbivores) (decomposers)
Energy is lost as heat or used by the organism through each trophic level Only 10% of energy is passed from one trophic level to the next = 10% Rule
KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem.
A food chain is a model that shows a sequence of feeding relationships. Algae Zooplankton Small Fish Squid Shark
A food web shows a complex network of feeding relationships and energy flow. An organism may have multiple feeding relationships in an ecosystem. A food web is made up of interconnected food chains.
Types of Ecological Pyramid An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. 1) Energy Pyramid - shows the relative amount of energy at each trophic level (kcal) - only part of the energy at each level is passed on to the next level 0.1% Tertiary consumers 1% Secondary consumers 10% Primary consumers 100% Producers
Types of Ecological Pyramid 2) Numbers Pyramid - shows the relative number of organisms at each trophic level
Types of Ecological Pyramid 3) Biomass Pyramid - compares the total amount of living tissues at each trophic level - biomass is usually expressed in terms of grams of organic matters per unit area - represents the amount of potential food available for each trophic level
An ecosystem includes: 1) Abiotic factors nonliving components of an ecosystem (sunlight, precipitation, temperature, water, atmosphere etc) 2) Biotic factors living components of an ecosystem (organisms) Community Ecosystem Ecosystem Community Population Population Organism Organism
A biome is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there. Biome Ecosystem Ecosystem Community Community Organism Population Population Organism
Biosphere is the part of Earth where life exists. Biome Ecosystem Ecosystem Community Community Organism Population Population Organism
A habitat differs from a niche. Habitat physical area in which an organism lives Niche each species plays a specific role in an ecosystem niche includes the species habitat, feeding habits, behaviors etc.
KEY CONCEPT Organisms interact as individuals and as populations.
Competition and predation are two important ways in which organisms interact. Competition occurs when two organisms fight for the same limited resource. Intraspecific competition: within the same species Interspecific competition: between two different species
Predation occurs when one organism feeds on another. as population of prey rises, there will be a corresponding rise in predator population and vice versa prey and predator species coevolve
Symbiosis is a biological relationship where organisms of 2 different species live in a close association Three types of symbiotic relationship: 1) Mutualism - both organisms benefit from living together - ex. bacteria in digestive tract of cattle bacteria benefit by having food and a home cattle benefits by being able to digest grass
2) Parasitism - one organism benefits, the other organism is harmed ex. 1: ticks (parasite) living on other animals (host) leech hookworm
2) Parasitism - one organism benefits, the other organism is harmed ex. 2: wasp larvae (parasites) feed on caterpillar (host) _ Hornworm caterpillar The host hornworm will eventually die as its organs are consumed by wasp larvae. Parasitism 0 + Braconid wasp Braconid larvae feed on their host and release themselves shortly before reaching the pupae stage of development. _ Organism is harmed 0 Organism benefits
3) Commensalism - one organism benefits, the other organism is neither harmed nor benefits ex. 1: epiphytes (smaller plants living on larger plants) Spanish moss hangs on tree but does not harm the tree.
3) Commensalism - one organism benefits, the other organism is neither harmed nor benefits ex. 2: mites living in human eyelashes Ø Human Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle. Commensalism + Demodicids Eyelash mites find all they need to survive in the tiny follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. Ø Organism is not affected + Organism benefits