44 terms

Chapter 3: The Biosphere - Biology

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biosphere
consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere
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
ecology
the study of interactions of organisms in the biosphere between surroundings and each other
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
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, soul type, and so on
What is ecology?
Ecology is the scientific study of interactions among organisms and between organisms and their physical environment
What are biotic and abiotic factors?
The biological influences on organisms are called biotic factors. Physical components of an ecosystem are called abiotic factors
What methods are used in ecological studies?
Modern ecologists use three methods in their work: observation, experimentation, and modeling. Each of these approaches relies on scientific methodology to guide inquiry
autotroph
use solar or chemical energy to produce "food" by assembling inorganic compounds into complex organic molecules
primary producer
autotrophs other name because they store energy in forms that make it available to other organisms
photosynthesis
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
chemical energy is used to produce carbohydrates
heterotroph
must acquire energy from other organisms - by ingesting them in one way or another
consumer
heterotrophs other name
carnivore
kill and eat other animals
herbivore
obtain energy and nutrients by eating plant leaves, roots, seeds, or fruits
scavenger
animals that consume the carcasses of other animals that have been killed by predators or have died of other causes
omnivore
animals whose diets naturally include a variety of different foods that usually include both plants and animals
decomposer
"feed" by chemically breaking down organic matter
detritivore
feed on detritus particles, often chewing or grinding them into even smaller pieces
What are primary producers?
Primary producers are the first producers of energy-rich compounds that are later used by other organisms
How do consumers obtain energy and nutrients?
Organisms that rely on other organisms for energy and nutrients are called consumers
food chain
a series of steps in which organisms transfer energy by eating and being eaten
phytoplankton
photosynthetic algae found near the surface of the ocean
food web
network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem
zooplankton
small free-floating animals that form part of plankton
trophic level
each step in a food chain or food web
ecological pyramid
shows 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 energy flow through ecosystems?
energy flows through an ecosystem in a one-way stream, from primary producers to various consumers
What do the three types of ecological pyramids illustrate?
Pyramids of energy show the relative amount of energy available to 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 of an ecosystem. A pyramid of numbers shows the relative number of individual organisms at each trophic level in an ecosystem
biogeochemical cycle
process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another
nutrient
the chemical substances that an organism needs to sustain life
nitrogen fixation
process of converting nitrogen gas into nitrogen compounds that plants can absorb and use
denitrifaction
process by which bacteria convert nitrates into nitrogen gas
limiting nutrient
the nutrient whose supply limits productivity
How does matter move through the biosphere?
Unlike the one-way flow of energy, matter is recycled within and between ecosystems
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 nutrients 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 carbon, nitrogen, and phosphorus cycles are especially critical for life
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
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