Flashcards in Ecosystem Ecology Deck (117):
the unit composed of all the living things in a single place at a given time, in addition to, the important non-living components of the system.
encompasses all aspects of a biological community, in addition to factors such as rates of CO2 uptake, rates of nitrogen fixation from the atmosphere, precipitation, seasonal flooding and its effects on nutrients, etc.
the largest and most encompassing ecosystem we know-it encompasses all the plants and animals on Earth.
Like communities, small ecosystems are “stacked” within larger ones, and the boundaries are sometimes diffuse.
Much of this discipline concerns itself with the flow of energy and biomass.
These two things are common to all biological communities
Nutrient Cycling and Energy Flow
The complex matrix of interactions among members of a community expends energy, as well as passing it from one member to the next through...
Likewise, biomass is constantly recycled through these 4 things
Production, Predation, Herbivory, and Decomposition
The ultimate energy source for almost every ecosystem on earth.
These are a partial exception-(they rely on geothermal energy, but still depend upon oxygen fixed by photosynthetic organisms).
Hydrothermal Vent Communities
Energy enters ecosystems via this process
Photosynthesis (or, in a few exotic excosystems, chemosynthesis).
Organisms that bring energy into an ecosystem are called
Include green plants, algae, cyanobacteria, etc..anything that can make its own energy from nonliving components of the environment.
All metabolic processes consume energy in some way, and in each reaction, much of it is effectively “wasted”…
Why are humans homeothermic? (Why do we generate our own heat?)
The wasted heat from metabolic processes, mostly as molecular motion, warms our bodies.
Ultimately, all biological energy radiates into the environment as
a by-product of respiration
Much energy is lost every time it passes from one trophic level to the next
Does energy recycle on Earth?
No, it is continually replenished from the sun
Recycles through ecosystems
Atoms of every biologically important element constantly recycle through ecosystems, into the abiotic component of the biosphere, and back into living systems.
How are elements passed from one organism to another?
OR they are taken from the environment
Process that causes nonliving elements to have the potential to re-enter the atmosphere again
The path an element takes as it moves from abiotic systems through producers, consumers, and decomposers and back again
Biogeochemical Cyclye (life-Earth-chemical)
a schematic diagram that describes the trophic interactions in a community and documents energy flow
also a trophic interaction that uses up the energy left over in dead bodies of organisms.
one path through a food web, from bottom to top.
Because energy is lost at each step, food chains have a limited number of links.
defined as the weight of living matter (usually measured in dry weight per unit area).
a figure that quantifies the relative amounts of living biomass found at each trophic level.
Pyramid of Biomass
In most ecosystems, the amount of biomass found in each trophic level increases or decreases progressively as one moves from the bottom to the top of the food chain?
The most important producers vary from ecosystem to ecosystem.
In cold-water marine systems, for instance, it may be a mixture of photosynthetic haplophytes, diatoms, and dinoflagellates.
Producers vary from ecosystem to ecosystem
Northern coniferous forests typically have a few dominant species of trees, such a pine, spruce, hemlock, cedar.
Tropical rain forests may support hundreds of species of trees.
Producers vary from ecosystem to ecosystem
Producer from ancient ecosystem that is a horsetail which formed colossal forests
Producer from ancient ecosystem which is a seed fern that covered vast continents
Producer from an ancient ecosystem that is an enigmatic seed ferm or gymnosperm that dominated during the breakup of Pangea
Producers- Spirulinia sp.,
Sea kelp, Ancient trees
Examples of producers
Primary consumers eat..
Do they possess more or less biomass than producers?
In most ecosystems only a small amount of producer biomass is eaten (plants have evolved numerous mechanisms to protect tissues from consumption)
Why does a loss of biomass occur between trophic levels?
Digestive inefficiences and the return of CO2 to the atmosphere via cellular respiration
Assimilation efficiencies for most terrestrial herbivores range from
These consume primary consumers.
These consume secondary consumers
Who has higher assimilation efficiences, carnivores or herbivores?
Carnivores (50-90 percent)
So why does only a small amount of assimilated energy become biomass in carnivores?
Used towards metabolic energy needs of body maintenance, growth, reproduction, and locomotion
Ankylosaur, pipevine swallow tail, and barrel cactai adapt to avoid participating in trophic transfer
How many levels do food chains have typically?
Four or five
Less biomass occurs at higher trophic levels because
There is less energy available to consumers
an organism that exists on the top of several or all food chains in the ecosystem
may feed at various trophic levels, but ultimately, nothing (except parasites) eats them
They are a reflection of the ecosystem as a whole-low productivity environments support fewer and less-impressive apex predators
For instance, fossil localities in arid environments do not have Tyrannosaurus rex fossils. We can infer that abundant hervivores, and extensive vegetation, were necessary to support populations of this species.
YEA! some examples:
are organisms that eat dead organic matter
eat the dead bodies of living things, such as carrion, leaf litter, etc
are animals that eat dead animals. Most apex predators also do this
microscopic organisms that break down organic compounds into nonliving, inorganic precursors.
organisms that feed on dead organic matter, this term is usually applied to fungi or bacteria, but there are plant ones as well
the amount of biomass produced through photosynthesis per unit area and time by producers.
It is usually expressed in units of energy (e.g., joules /m2 day) or in units of dry organic matter (e.g., kg /m2 year).
Globally, primary production amounts to how much dry plant biomass per year.?
243 billion metric tons
The total energy fixed by plants in a community through photosynthesis is referred to as
Gross Primary Productivity (GPP)
Most gross primary productivity is used via respiration by the producers themselves.
Subtracting respiration from gross primary production gives
Net Primary Productivity (NPP)
represents the rate of production of biomass that is available for consumption (herbivory) by heterotrophic organisms (bacteria, fungi, and animals). It is also easier to measure, because it tends to accumulate over time.
Net Primary Productivity (NPP)
Globally, patterns of primary productivity vary both spatially and temporally
The least productive ecosystems are limited by heat energy, nutrients and water like the deserts and the polar tundra.
The most productive ecosystems have high temperatures, plenty of water and lots of available soil nitrogen.
Productivity is high in areas of
Oceanic producers include
Diatoms, dinoflagellates crptomonads, and other algae that require nutrients
Each biologically important element has a
the path of an element from one organism to another, and from organisms into the nonliving part of the biosphere and back
Another way to refer to a nutrient cycle that reflects the fact that chemicals are cycled between biological organisms, and between organisms and the geologic (physical) environment.
The non-living forms of carbon, hydrogen, oxygen, and nitrogen form huge ones of these in the physical environment
For example, how much of the atmosphere does Nitrogen (N2) make up?
A supply of a biologically meaningful element that is not easily obtainable by living organisms.
Elements can have multiple of them
This biogeochemical cycle has reservoirs in the ocean, also in freshwater lakes and underground aquifers
Driven by energy transfer from the sun, evaporation over oceans and rainfall over oceans and continental interiors
This biogeochemical cycle element has reservoirs in the atmosphere, also in fossil deposits, soil, marine sediments
Driven by plate tectonics and biological processes
Biogeochemical cycle that has reservoirs in the atmosphere, driven by lightning and vulcanism, also by activities of nitrogen fixing microbes and dentrifying microbes
Biogeochemical cycle that has reservoirs of rocks and minerals, driven by erosion but also by the mass movement and decomposition of animals like salmon
Makes up the bulk of most living things-it is the primary constituent of biomass, but is relatively scarce in the nonliving part of the Eart
Exists in non-living environment as carbon dioxide, dissolved carbon dioxide (HCO3, etc) in the ocean, and it carbonates the Earth's crusts
Furthermore, is locked in fossil deposits and embedded in the ocean floor as deposits of methane anhydride
While carbon makes up less than 1% of the atmosphere, it is very important in the biosphere.
means capture and conversion to a biologically useful form.
Eg., water does not need to be “fixed”, neither does sodium, but carbon and nitrogen do.
This molecule is fixed by plants during photosynthesis
CO2,. once fixed during photosynthesis, is converted into these molecules by combining it with water.
Once fixed, how does CO2 pass through the food chain? Up or Down? How?
Up, through herbivory and predation
Most organisms, including plants, do this process which liberates carbon back into the atmosphere and provides energy to the organism
After respiration, CO2 enters the atmosphere. If not eaten and respired, or decomposed, what might happen to organic carbon?
My become buried and enter a carbon reservoir in the soil and ultimately fossilize
This element can return to the atmosphere if plant material is burned, naturally or through human activities
Ancient plant and animal material with carbon was fixed and turned into this which returns carbon to the atmosphere when burned
This element can also be recycled back into the atmosphere through volcanic activity
When a tectonic plate goes underneath a continent, superheated oceanic material upgasses through geological vents and reenters the atmosphere
Why does CO2 have a crucial role in the climate of earth in terms of light properties?
1. It is quite transparent to light at visible wavelengths
2. It is relatively opaque to infrared light
Gasses with the CO2 light properties that tend to trap heat and force a higher equilibrium vapor pressure
Most important greenhouse gas because it occurs at higher concentrations
Low global temperatures
High global temperatures
In the Miocene, 15 million years ago, a sudden increase in CO2 caused
a sudden warming of the climate
What does evidence show is the cause of increased CO2 concentrations over the last 150 years?
Burning of fossil fuels and deforestation
When was fossilized carbon fossilized?
During the Carboniferous period, 300 million years ago
Why is the surface temperature of Venus so hot?
The Greenhouse Effect
What does this suggest about Venus' climate in the past?
Venus had a much more earthlike climate, but its oceans evaporated
Three changes we might already be seeing in our world
Sea Ice melting
Local changes in climate
Possible acidification of the Oceans
One of the most common elements that form biological molecules.
It is a major component of amino acids, also a primary constituent of nucleic acids.
What makes N2 a very stable molecule and biologically inert?
The triple bond
A large amount of energy is required to break this bond
N2 (triple bond)
Lightning is responsible for converting the molecule in the atmosphere into forms that organisms can use
The process of converting atmospheric nitrogen into forms that organisms can use is called
Some free-living soil bacteria as well as some blue-green bacteria in the genera Anabaena and Nostoc have the ability to convert nitrogen into ammonia, including...
Nitrogen is also fixed by symbiotic bacteria that live in and among the root cells of several types of plants, including this plants which have root nodules
Legume plants (beans, peanuts, peas)
Other plants, have nitrogen fixing cyanobacteria like the..
Decomposed compounds of nitrogen become...
Ammonia, Nitrates, Nitrite
The process that nitrogen in organisms is converted to ammonia, nitrates, and nitrite is
These convert nitrites and nitrates in the soil to N2O and N2, which returns to the reservoir in the atmosphere.
The process which completes the nitrogen cycle, is
is one of the most important processes to living organisms on Earth.
Has evaporated into the atmosphere condenses and falls as precipitation
precipitation will either run off as surface water and collect as streams or rivers, or it can seep into the ground and collect in huge underground rock formations called
The water eventually flows from lakes or streams down into the oceans, where it can reside for long periods of time, or get evaporated back up into the atmosphere as water vapor, which collects as
A portion of the groundwater is taken up by plants and used for solute transport, metabolism, and structural support-it is continuously lost to the atmosphere by