43 terms

Chapter 3 - The Biosphere

Miller & Levine Biology Core Edition Inside: 3.1 - What Is Ecology? 3.2 - Energy, Producers, and Consumers 3.3 - Energy Flow in Ecosystems 3.4 - Cycles of Matter
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Terms in this set (...)

Biosphere
Consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere.
What is ecology?
Ecology is the scientific study of interactions among organisms and between organisms and their physical environment.
Ecology
The study of interactions of organisms in the biosphere.
Species
A group of similar organisms that can breed and produce fertile offspring.
Population
A group of individuals that belong to the same species and live in the same area.
Community
An assemblage of different populations that live together in a defined area.
Ecosystem
All the organisms that live in a place together with their physical environment.
Biome
A group of ecosystems that share similar climates and typical organisms.
What are biotic and abiotic factors?
The biological influences on organisms are called biotic factors. Physical components of an ecosystem are called abiotic factors.
Biotic Factor
Any living part of the environment with which an organism might interact, including animals, plants, mushrooms, and bacteria.
Abiotic Factor
Any nonliving part of the environment, such as sunlight, heat, precipitation, humidity, wind or water currents, soil type, and so on.
What methods are used in ecological studies?
Regardless of their tools, modern ecologists use three methods in their work: observation, experimentation, and modeling. Each of these approaches relies on scientific methodology to guide inquiry.
What are primary producers?
Primary producers are the first producers of energy-rich compounds that are later used by other organisms.
Autotrophs
Organisms that capture energy from sunlight or chemicals and convert it into forms that living cells can use.
Primary Producers
Autotrophs
Photosynthesis
A process that captures light energy and uses it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugars and starches.
Chemosynthesis
A process that uses chemical energy to produce carbohydrates.
How do consumers obtain energy and nutrients?
Organisms that rely on other organisms for energy and nutrients are called consumers.
Heterotrophs
Organisms that must acquire energy from other organisms- by ingesting them in one way or another.
Consumers
Heterotrophs
Carnivores
Kill and eat other animals.
Examples: snakes, dogs, cats, river otters, etc.
Herbivores
Obtain energy and nutrients by eating plant leaves, roots, seeds, or fruits.
Examples: cows, caterpillars, deer, etc.
Omnivores
Obtain energy and nutrients from both plants and animals.
Examples: humans, bears, pigs, etc.
Scavengers
Animals that consume the carcasses of other animals that have been killed by predators or have died of other causes.
Example: vultures, etc.
Decomposers
Obtain energy and nutrients by chemically breaking down organic matter.
Examples: bacteria, fungi, etc.
Detritivores
Organisms that feed on detritus particles, often chewing or grinding them into even smaller pieces. They commonly digest decomposers that live on, and in, detritus particles.
Examples: earthworms, mites, snails, shrimp, crabs, etc.
How does energy flow through ecosystems?
Energy flows through an ecosystem in a one-way stream, from primary producers to various consumers.
Food Chain
A series of steps in which organisms transfer energy by eating and being eaten.
Phytoplankton
Floating algae that mixes with attached algae that are primary producers in some aquatic food chains.
Food Web
A complicated network of feeding interactions.
Zooplankton
Small, swimming animals that feed on marine algae.
What do the three types of ecological pyramids illustrate?
Pyramids of energy show the relative amount of energy available at each trophic level of a food chain or food web. A pyramid of biomass illustrates the relative amount of living organic matter available at each trophic level in an ecosystem. A pyramid of numbers shows the relative number of individual organisms at each trophic level in an ecosystem.
Ecological Pyramids
Show the relative amount of energy or matter contained within each trophic level in a given food chain or food web.
Biomass
The total amount of living tissue within a given trophic level.
How does matter move through the biosphere?
Unlike the one-way flow of energy, matter is recycled within and between ecosystems.
Biogeochemical Cycles
Closed loops where elements pass from one organism to another and among parts of the biosphere.
How does water cycle through the biosphere?
Water continuously moves between the oceans, the atmosphere, and land- sometimes outside living organisms and sometimes inside them.
What is the importance of the main nutrient cycles?
Every organism needs nutrients to build tissues and carry out life functions. Like water, nutrients pass through organisms and the environment through biogeochemical cycles. The three pathways, or cycles that move carbon, nitrogen, and phosphorus through the biosphere are especially critical for life.
Nutrient
The chemical substances that an organism needs to sustain life.
Nitrogen Fixation
A process where bacteria convert nitrogen gas into ammonia.
Denitrification
A process where soil bacteria obtain energy by converting nitrates into nitrogen gas, which is released into the atmosphere.
How does nutrient availability relate to the primary productivity of an ecosystem?
If ample sunlight and water are available, the primary productivity of an ecosystem may be limited by the availability of nutrients.
Limiting Nutrient
The nutrient whose supply limits productivity.

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