: Ecology
The branch of biology that deals with the study of the interactions among organisms and with their environment.
: Ecologists
Scientists who study ecology.
: Ecosystems
Consist of the physical environment and all the living things within that environment.
: Abiotic Factors
Non-living things that make up the physical environment (e.g., water, atmosphere, soil, temperature).
: Biotic Factors
Living things within the physical environment (e.g., plants, animals, fungi, bacteria).
: Terrestrial Ecosystem
An ecosystem contained on land (e.g., continents, islands where water is a limiting factor).
: Aquatic or Marine Ecosystem
An ecosystem contained in water (e.g., freshwater – lakes and rivers, saltwater/marine – oceans).
: Trophic Levels
Define the roles of organisms in an ecosystem based on the energy and nutrients they contribute, consume, or recycle.
: Autotrophs
Organisms that create their own carbon compounds from carbon dioxide and other simple substances (e.g., plants, algae).
: Heterotrophs
Organisms that obtain carbon compounds from other organisms (e.g., animals, fungi, bacteria).
: Producers
Autotrophs that trap energy in sunlight and convert it to carbohydrates (e.g., plants, algae).
: Primary Consumers
Heterotrophs that obtain energy from producers.
: Secondary Consumers
Heterotrophs that obtain energy from primary consumers.
: Tertiary Consumers
Heterotrophs that obtain energy from secondary consumers.
: Omnivores
Organisms that feed on both producers and consumers.
: Detritivores
Heterotrophs that obtain nutrients from detritus by internal digestion (e.g., earthworms).
: Decomposers
Organisms that consume dead plant and animal remains and convert them into reusable substances (e.g., bacteria, fungi).
: Scavengers
Organisms that eat dead animal remains to obtain energy (e.g., vultures, hyenas).
: Saprotrophs
Heterotrophs that obtain nutrients from dead organic matter by external digestion (e.g., bacteria, fungi).
: Energy in Ecosystems
Most ecosystems rely on the sun to supply energy, which is harvested by living organisms through photosynthesis.
: Photosynthesis
Process performed by autotrophs such as plants, eukaryotic algae, and cyanobacteria to convert light energy into chemical energy.
: Heterotrophs
Organisms that do not use light energy directly but are indirectly dependent on it by using carbon compounds from producers.
: Producers
Organisms that absorb sunlight using chlorophyll and other photosynthetic pigments to produce carbohydrates and other carbon compounds.
: Cellular Respiration
Process by which producers use energy for their cellular activities, resulting in energy loss as heat.
: Food Chain
Sequence of organisms through which energy is passed, usually between 2-5 organisms.
: ATP
Compound that supplies energy for cellular activities, created by breaking down carbon compounds.
: Energy Losses in Ecosystems
Only 10% of the energy consumed or created by an organism gets passed on to the next trophic level, with the rest lost as heat.
: Ecological Pyramids
Visual representations of the populations involved in a feeding relationship, including pyramids of numbers, biomass, and energy.
: Pyramid of Numbers
Diagram showing the relative number of organisms decreases as we move up trophic levels.
: Pyramid of Biomass
Diagram showing the mass of organisms in a given area, with producers generally having greater biomass than consumers.
: Pyramid of Energy
Diagram representing the amount of energy converted to new biomass by each trophic level, measured in units of energy per unit area per unit time.
: Food Webs
Models summarizing all possible food chains in a community, showing complex feeding relationships.
: Top Carnivores
Organisms at the top of a food web with no predators, not including humans.
: Symbiosis
Relationships between organisms that do not involve one species eating another.
: Mutualism
Symbiotic relationship where both organisms benefit.
: Commensalism
Symbiotic relationship where one organism benefits and the other is unaffected.
: Parasitism
Symbiotic relationship where one organism benefits while harming the other.
: Species
A group of organisms that can interbreed and produce fertile offspring.
: Population
A group of organisms of the same species living in a given area at the same time.
: Community
Populations living together and interacting with each other.
: Niche
The unique combination of spatial habitat and interactions with other species in an ecosystem.
: Population Growth
Exponential growth occurs under ideal conditions, producing a “J” shaped curve.
: Carrying Capacity
The number of individuals of a population that can survive in a given area.
: Limiting Factors
Factors that influence the size of a population, including materials and energy, food chains, competition, and density.
: Population Growth Curve
Shows how population growth is affected by environmental resistance, with stages of exponential growth, transitional phase, and plateau phase.
: Intraspecific Competition
Competition between members of the same species.
: Interspecific Competition
Competition between members of different species.
: Competitive Exclusion Principle
Two species cannot indefinitely occupy the same habitat if their niches are identical.
: Fundamental Niche
The potential mode of existence given the adaptations of a species.
: Realized Niche
The actual mode of existence, resulting from both adaptations and competition.
: Density Dependent Limiting Factors
Factors that affect populations as the population size increases (e.g., disease, aggression, stress).
: Density Independent Limiting Factors
Factors that affect populations regardless of size (e.g., flood, fire, tornado, hurricane).
: Species
A group of organisms that can interbreed and produce fertile offspring.
: Population
A group of organisms of the same species living in a given area at the same time.
: Community
Populations living together and interacting with each other.
: Niche
The unique combination of spatial habitat and interactions with other species in an ecosystem.
: Population Growth
Exponential growth occurs under ideal conditions, producing a “J” shaped curve.
: Carrying Capacity
The number of individuals of a population that can survive in a given area.
: Limiting Factors
Factors that influence the size of a population, including materials and energy, food chains, competition, and density.
: Population Growth Curve
Shows how population growth is affected by environmental resistance, with stages of exponential growth, transitional phase, and plateau phase.
: Intraspecific Competition
Competition between members of the same species.
: Interspecific Competition
Competition between members of different species.
: Competitive Exclusion Principle
Two species cannot indefinitely occupy the same habitat if their niches are identical.
: Fundamental Niche
The potential mode of existence given the adaptations of a species.
: Realized Niche
The actual mode of existence, resulting from both adaptations and competition.
: Density Dependent Limiting Factors
Factors that affect populations as the population size increases (e.g., disease, aggression, stress).
: Density Independent Limiting Factors
Factors that affect populations regardless of size (e.g., flood, fire, tornado, hurricane).
: Nitrogen in Atmosphere
Almost 80% of our atmosphere is composed of Nitrogen gas (N2).
: Importance of Nitrogen
Nitrogen is necessary for the composition of all amino acids and genetic material.
: Nitrogen Cycle
The process by which nitrogen is converted between its various chemical forms, making it available to living organisms.
: Nitrogen Fixation
The conversion of unusable nitrogen gas in the atmosphere to ammonia (NH3).
: Methods of Nitrogen Fixation
Lightning strike, bacteria in root nodules (e.g., beans, peas, clover), and free-living bacteria in the soil.
: Diazotrophs
Bacteria that have the ability to fix nitrogen.
: Rhizobia
Bacteria found in root nodules that fix nitrogen.
: Azotobacteraceae
Free-living bacteria in the soil that fix nitrogen.
: Ammonification
The conversion of dead organic matter and animal waste into ammonia by decomposers such as bacteria and fungi.
: Nitrification
The process of converting ammonia into nitrates (NO3-) and nitrites (NO2-) by free-living bacteria in the soil.
: Nitrosomonas
Bacteria that convert ammonia into nitrites (NO2-).
: Nitrobacter
Bacteria that convert ammonia into nitrates (NO3-).
: Denitrification
The conversion of nitrates back into nitrogen gas under anaerobic conditions in the soil.
: Denitrifying Bacteria
Bacteria such as Clostridium and Pseudomonas that perform denitrification.
: Phosphorus in Living Things
Required to produce molecules such as DNA and ATP, and maintain vertebrate skeletons and cell membranes.
: Phosphorus Cycle
The process by which phosphorus moves through the lithosphere, hydrosphere, and biosphere.
: Terrestrial Phosphate
Weathering of rocks adds inorganic phosphate (PO43-) to the soil, which plants assimilate.
: Aquatic Phosphate
Phosphate from terrestrial ecosystems drains into bodies of water, where it may settle and become part of new rock.
: Phosphate in Ecosystems
Phosphate transfers from terrestrial to aquatic ecosystems faster than it is replaced, diminishing terrestrial phosphate over time.
: Waste
The large population of humans creates increasing amounts of waste and chemicals to control pests.
: Biodegradable Waste
Waste that can be decomposed naturally by the ecosystem
: Non-Biodegradable Waste
Waste that cannot be decomposed naturally by the ecosystem, such as plastics, styrofoam, metal, and glass.
: The Great Pacific Garbage Patch
A large area in the North Pacific Gyre made up of small plastics, not a floating island of garbage.
: Bioaccumulation
The build-up of chemicals in the body of an organism.
: Biomagnification
The increasing concentration of toxic substances within living organisms as you move up the food chain.
: DDT Example
DDT introduced into an environment through spraying for mosquitoes, building up in organisms as you move up the food chain.
: Eutrophication
The build-up of nutrients in an aquatic ecosystem, often caused by excess nitrogen and phosphorus from human activities.
: Algal Bloom
Aggressive growth of algae on the surface of water, blocking sunlight and reducing oxygen levels.
: Hypoxia
A condition where there is not enough oxygen in the water to sustain life.
: Endemic Species
Species native to a specific area.
: Alien Species
Species introduced to an area by humans.
: Invasive Species
Alien species that spread rapidly and cause harm to the environment.
: Greenhouse Gases (GHGs)
Gases like CO2 and methane that trap heat in the atmosphere.