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Bio: Chapter 3 The Biosphere

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ecology
the scientific study of interactions among organisms and between organisms and their environment.
Hackckel
German biologist who named ecology in 1866. 'oikos' is greek for house. He saw the living world as a house-hold with an economy in which each organism plays a role.
biosphere
contains combined portions of the plane in which all of life exists (land, water, air/atmosphere).
The highest level of organization ecologists suds.
Extends 8km above surface and 11km below surface of ocean.
Interactions within produce web of interdependence between organisms and environment in which they live. This contributes to the dynamic biosphere.
dynamic
ever-changing
Levels of Organization
To understand relationships within biosphere, ecologists ask questions about events and organisms that range in complexity from single individuals o an entire biosphere.
species
group of organisms so similar to one another that they breed and produce fertile offspring.
Biologists that focus on species level study interactions between particular kinds of organisms and its surroundings.
populations
groups of individuals that belong o same species and live in the same area.
communities
assemblages of different populations that live together in a defined area.
ecosystems
collection of all organisms that live in particular place (community) together with their nonliving, physical environment.
biome
group of ecosystems that have same climate and similar dominant communities.
Ecological methods
possible tools and techniques used: binoculars and field guides to assess changes in plant and wildlife communities; studies of DNA to identify bacteria in mud of coastal marshes; radio tags to track migrating wildlife or data gathered by satellites.
Scientists conduct modern ecological research using 3 basic approaches. All of these approaches rely of the application of scientific methods to guide ecological inquiry.
Observing
The first step of ecological methods. It is as simple as asking: what species live here, how many individuals are there, or as complex as: forming the first step in designing experiments and models.
Experimenting
Experimenting s used to test hypotheses. Either conducted in an artificial environment in a lab to imitate and manipulate it or in natural ecosystems where organisms encounter the natural world.
Modeling
Many ecological phenomena occur over long periods of time or on such a large spatial scales that they are different to study. Models are made to gain insight into the complex phenomena, such as global warming effects on ecosystems. Many models consist of mathematical formulas based on data collected through observation and experimentation. Predictions made by models are often tested further by observation and experiments.
Energy flow
the core of every organism's interaction with the environment is its need for energy, which powers life's processes.
The flow of energy through an ecosystem is one of the most important factors, it determines the system's capacity to sustain life.
Producers
living systems need a constant input of energy.
Sunlight is the main energy source for life of Earth. Less than 1% of the sun's energy that reaches Earth's surface is used by living things - enough to produce 3.5kg of living tissues per square meter per year in some tropical forests.
Some types of organisms rely on energy stored in inorganic chemical compounds - such as mineral water from underground, hot springs, or undersea vent that are loaded with chemical energy.
autotrophs
Organisms that capture energy from sunlight or chemical and use that energy to produce food. They use energy from the environment to fuel the assembly of simple inorganic compounds into complex organic molecules. They combine and recombine to produce living tissue.
producers
Organisms that make their own food, also known as autotrophs. There are two types, those that capture energy from sunlight and those that capture chemical energy.
Producers are essential to the flow of energy through the biosphere.
Photosynthesis
Process in which autotrophs use light energy to power chemical reactions that convert C02 + H2O into O2 + C6H12O6 (sugars and starches). The process is responsible for adding O2 to and removing CO2 from the Earth's atmosphere.
Photosynthetic autotrophs
Photosynthetic autotrophs are the best-known autographs are those that harness solar energy.
They allow us to breathe.
Main autotrophs: land - plants; freshwater ecosystems and the sunlit upper layers of the ocean - algae. Photosynthetic bacteria, the most common cyanobacateria, is important in certain wet ecosystems (tidal flats, salt marshes).
Chemosynthesis
Process in which organisms use chemical energy to produce carbohydrates. Autotrophs rely on energy within chemical bonds of inorganic molecules (hydrogen sulfide).
Performed by several types of bacteria, with represent a large portion of living autotrophs. They live in very remote places like volcanic vents, hot springs, and tidal marshes.
heterotrophs/consumers
organisms that rely on other organisms for their energy and food supply.
Animals, fungi, many types of bacteria.
Cannot harness energy directly from their physical environment, therefore must acquire energy from other organisms.
herbivores
obtain energy by eating only plants.
Cows, caterpillars, deer.
carnivores
organisms that eat other animals.
Snakes, dogs, owls.
omnivores
organisms that eat both plants and animals
detritivores
organisms that feed on plant and animal remains and other detritus.
Mites, earthworms, snails, crabs
detritus
dead matter
decomposers
organisms that break down organic matter.
bacteria, fungi.
feeding relationships
energy flows through ecosystems in one direction. From the sun/inorganic compounds to autotrophs (producers) to various heterotrophs (consumers).
Relationship between producers and consumers connect organisms into feeding networks based on who eats whom.
food chain
series of steps in which organisms transfer energy by eating or being eaten.
Energy stored by producers can be passed through an ecosystems along a food chain.
From producer to herbivore to carnivore - 2 steps removed from producer.
If there are 2 carnivores - top is 4 steps removed from producer.
food web
feeding relationships among various organisms in an ecosystem to form a network of complex interactions.
food web links all food chains in an ecosystem together.
more complex than food chain.
trophic level
each step in a food chain or web.
producers - first trophic level
consumers - second/third + trophic level.
each level depends on the level below for energy.
ecological pyramid
diagram that shows relative amounts energy/matter contained within each trophic level of a food chain or web.
represents the amount of energy/matter in an ecosystem.
3 types: energy, biomass, pyramid of numbers
tens rule
In energy pyramid, 10% of energy available within one trophic level is transferred to organisms of the next.
energy pyramid
only part of energy stored is passed from one level to next - organisms use much of energy they consumer for life processes: respiration, movement, reproduction. Some remaining energy released into the environment as heat.
Theoretically, no limit to number of trophic levels a food chain can support.
biomass
total amount of living tissue within a trophic level.
Usually expressed in terms of grams of organic matter per unit area.
biomass pyramid
biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.
pyramid of numbers
based on the numbers of individual organisms at each trophic level.
Some are shaped the same as that of biomass pyramids - energy = numbers.
But not always - a large tree provides energy for many organisms, but it is still 1 organism.
cycles of matter
Energy is crucial to an ecosystem.
All organisms need more than just energy to survive - water, minerals, other life-sustaining compounds.
Most organisms: 95% + of the body is made up of 4 elements - oxygen, carbon, hydrogen, nitrogen. Common on Earth but only usable in chemical form that cells can take up.
recycling in the biosphere
energy and matter move through the biosphere very differently.
Unlike the one-way flow of energy, matter is recycled within and between different ecosystems.
elements
chemical compounds
biogeochemical cycle
cycle through which elements and other forms of matter are passed from one organism to another and from one part of the biosphere to another.
Connects biological, geological, chemical aspects of biosphere.
Matter can cycle through biosphere because biological systems do not use up matter, they transform it.
Matter assembled into living tissue or passed out of the body as a waste product.
Biogeochemical cycles pass the same molecules around again and again within the biosphere.
water cycle
all living things require water to survive.
Water moves between the ocean, atmosphere, and land.
Water molecules enter the atmosphere as water vapor - gas - when it evaporates from the ocean or other bodies of water.
During the day - the sun heats the atmosphere. The warm, moist air rises and it cools. Eventually, water vapor condenses to form tiny droplets that form clouds. When the droplets are large enough, precipitation occurs.
evaporation
process by which water enters the atmosphere as it changes from liquid form to atmospheric gas.
transpiration
process by which water enters the atmosphere by evaporating from the leaves of plants.
precipitation
rain, snow, sleet, hail.
Water returns to the Earth.
It runs along the ground into rivers/streams to the ocean/lake; seeps into soil into ground water (if deep enough)/to plants the roots, and cycle begins again.
nutrients
all chemical substances that an organism need to survive.
Food provides energy and nutrients (sustain life).
Nutrients are the body's chemical "building blocks".
nutrient cycles
Every living organism needs nutrients to build tissues and carry out essential life functions. Like water, nutrients are passed between organisms and the environment through biogeochemical cycles.
Producers obtain nutrients in simple inorganic forms consumers by other organisms.
Carbon cycle, nitrogen cycle, and phosphorus cycle are very important.
Oxygen participates in each by combining these elements and cycling with them during various parts of the journey.
Carbon cycle
Carbon plays many roles and is the key ingredient in living tissues.
4 main types of processes move carbon through its cycle: biological , geochemical, mixed biochemical, human activities.
biological process
Photosynthesis, respiration, decomposition.
Take up and release carbon and oxygen.
Geochemical processes
Corrosion, Volcanic activity.
Releases carbon dioxide to atmosphere and oceans.
Mixed biochemical processes
Burial and decomposition of dead organisms, conversion under pressure intro coal a petroleum - fossil fuels.
Store carbon underground.
Human activities
Mining, cutting and burning of forests, burning fossil fuels.
Release carbon dioxide into the atmosphere.
Nitrogen Cycle
all organisms require nitrogen to make amino acids to build proteins.
Nitrogen gas makes up 78% of the Earth's atmosphere. Nitrogen gas is the most abundant form of nitrogen.
Exists in several forms in the ocean.
Human activity adds to the biosphere in form of nitrate - a major component in plant fertilizers.
nitrogen fixation
process by which certain types of bacteria - which live in soil and on the roots of plants and legumes - convert nitrogen gas into ammonia.
Other bacteria in soil converts ammonia into nitrates and nitrites.
With the products available, it allows producers to make proteins, consumers eat and reuse nitrogen to make their own proteins.
denitrification
process by which certain soil bacteria converts nitrates into nitrogen gas.
When organisms die, decomposers return nitrogen to soil as ammonia, which is taken up again by producers.
Denitrification releases nitrogen into the atmosphere.
Phosphorus Cycle
Phosphorus is ssential to living organisms - forms part of life-sustaining molecules - DNA and RNA.
Phosphorus is not common in the biosphere - does not enter the atmosphere - remaining mostly on land (rocks, soil, minerals, ocean sediments) and exists in the form of inorganic phosphate. As the inorganic phosphate wears down, phosphate is gradually released.
Primary productivity (of an ecosystem)
Rate at which organic matter is created by producers.
Its controlling factor: the amount of available nutrients.
Limiting nutrient
single nutrient that is scarce or cycles slowly and limits and ecosystem.
Fertilizers boost productivity. The open-ocean is nutrient poor compared to land.
Algal bloom
Result of runoff from heavily-fertilized fields that causes an immediate increase in the amount of algae and other producers.
More nutrients available allows the producers to grow and reproduce more quickly. It can disrupt the equilibrium of an ecosystem.