Transcript Document

Food Relationships
Food web
• describes the eating relationships between
species within an ecosystem or a particular
living place.
• Many types of food chains or webs are
applicable depending on habitat or
environmental factors.
Food web
Trophic Levels
• describes the position that an organism
occupies in a food chain
• what an organism eats, and what eats the
organism.
Producers
• An autotroph is an organism that produces
complex organic compounds from simple
inorganic molecules
• using energy from light (by photosynthesis)
• plants & algae
• or inorganic chemical reactions (by
chemosynthesis)
• Bacteria in hydrothermal vents
Consumer
• A Heterotroph is an organism that uses
organic substrates to get its chemical energy
for its life cycle.
• This contrasts with autotrophs such as plants
which are able to directly use sources of
energy such as light to produce organic
substrates from inorganic carbon dioxide.
• Animals, Fungus eat other things
Consumers
Herbivores
• Herbivory is a form of predation in which an
organism, known as a herbivore, consumes
principally autotrophs
• such as plants, algae and photosynthesizing
bacteria.
• Herbivory is generally restricted to animals
eating plants.
• Organisms that feed on autotrophs are
known as primary consumers.
Herbivore
Carnivore
• A carnivore means meat eater
• An animal that derives its energy and nutrient
requirements from a diet consisting mainly or
exclusively of vertebrate and/or invertebrate
animal tissue, whether through predation or
scavenging
• A carnivore that sits at the top of the
foodchain is an apex predator.
Carnivores
omnivore
• Omnivores are species that eat both plants and animals as
their primary food source.
• They are opportunistic, general feeders not specifically adapted
to eat and digest either meat or plant material exclusively
• Crows are another example of an omnivore that many people see
every day
• There are reported cases of herbivores eating meat matter as
well as examples of carnivores eating plants, the classification
refers to the adaptations and main food source of the species in
general so these exceptions do not make either individual
animals nor the species as a whole omnivores.
detritivore
detrivore
• Detritivores are heterotrophs that obtain nutrients by
consuming detritus
• decomposing organic matter)
• They contribute to decomposition and the nutrient cycles.
• Detritivores are an important aspect of many ecosystems.
• They can live on any soil with an organic component, and even
live in marine ecosystems where they are termed
interchangeably with bottom feeders.
• Typical detritivorous animals include millipedes, woodlice, dung
flies, many terrestrial worms, burying beetles, some sedentary
polychaetes such as amphitrite, terebellids and fiddler crabs.
primary vs secondary vs
tertiary
• Primary Consumer - organism which gets its food from plants
(rabbit, squirrel, deer, mouse, honey bee, aphid, grasshopper,
tadpole, duck, black bear, mosquito, humpback whale, other
animals at times).
Secondary Consumer - organism which gets its food mainly
by eating primary consumers, but can also be prey itself.
(weasel, shrew, mole, merganser, snake, spider, frog, most fish,
other animals at times).
• Tertiary Consumer - organism which gets its food mainly by
eating other consumers, but rarely becomes prey itself. (hawk,
wolf, shark, fox, dragonfly, orca, human). APEX PREDATOR
Decomposer
• Decomposers and scavengers break down dead
plants and animals.
• They also break down the waste (poop) of other
organisms.
• Decomposers are very important for any ecosystem.
• If they weren't in the ecosystem, the plants would
not get essential nutrients, and dead matter and
waste would pile up.
• There are two kinds of decomposers, scavengers and
decomposers.
decomposers
biomass pyramid
• pyramid of biomass is a diagram of
different trophic levels in an ecosystem
• usually plotted as dry matter per unit area or
volume.
• Typically this gives a gradually sloping
pyramid, except where the sizes of organisms
vary dramatically from one trophic level to
another.
Biomass pyramid
Energy and Nutrients
• pyramid of energy is a diagram of the rates of flow
of energy through the different trophic levels of an
ecosystem.
• Each bar of the pyramid represents the amount of
energy per unit area or volume which flows through
that trophic level in a given time period.
• The pyramid reflects the rates of photosynthesis,
respiration, etc.
• pyramid of numbers is a diagram of the numbers
of individual organisms present at each trophic level
of an ecosystem.
Energy Pyramid
Energy Flow
• Energy flows in a one way direction
• At each level of the food chain, about 90% of the energy is lost
in the form of heat.
• The total energy passed from one level to the next is only about
one-tenth of the energy received from the previous organism.
• Therefore, as you move up the food chain, there is less energy
available.
• Animals located at the top of the food chain need a lot more
food to meet their energy needs.
• NOTE!! Each organism in the food chain is only transfering onetenth of its energy to the next organism.
Nutrient Cycling
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Energy does NOT cycle through an ecosystem, chemicals (Nutrients)
do.
Nutrients cycle through the organisms, the atmosphere, the oceans,
and rocks.
Since these chemicals cycle through both the biological and the
geological world, we call the cycles biogeochemical cycles.
Each chemical has its own unique cycle, but all of the cycles do have
some things in common.
Reservoirs are those parts of the cycle where the chemical is held in
large quantities for long periods of time.
The energy for transportation of chemicals is provided either by the
sun or by the heat released from the mantle and core of the Earth.
Sand County Almanac/Aldo
Leopold
• Aldo Leopold died in 1948 without seeing his book in print, but
when A Sand County Almanac was published in 1949 it spoke
his voice clearly and plainly, and has had a profound effect on
its readers ever since
• A Sand County Almanac is built around three main ideas:
• Land is a community of living things. This idea argues for the study
of ecology.
• Land is to be loved and respected. This idea argues for
conservation ethics.
• Land yields a harvest of culture. Leopold calls this "a fact long
known, but forgotten recently."