Transcript 42. Ecology Notes

Ecology
What is Ecology?
• Ecology is the study of interactions among
organisms (biotic factors) and between
organisms and their environment (abiotic
factors).
• Biotic factors- all the living things in the
environment
• Abiotic factors- all the nonliving things in the
environment ex. Temperature, light, water, soil
Levels of Organization
• Species is a group of organisms so similar to one
another that they can breed.
• Population are a group of individuals (of one type of
species) that belong to the same species that interbreed
and live in the same area.
• For example, all foxes living in an area form a
population.
• Another example, all dandelions growing in an area
form another population.
Levels of Organization
• Communities are assemblages of the different populations that
live together in a defined area.
• All the foxes, dandelions, grasshoppers, snakes, hawks, deer, and
skunks living in one area (forest) each form their individual
populations, but together make up a community.
• Ecosystem is a collection of all the organisms that live together in
a particular place as well as their nonliving or physical
environment. Ex. Forest or ocean
Levels of Organization
• Biome is a group of ecosystems that have the
same climate and similar dominant
communities.
• ex. Tropical rainforest, temperate deciduous
forest
• Biosphere contains the combined portions of
the planet in which life exists, including land,
water, and air or atmosphere.
Energy Flow
• Sunlight is the main source of energy for life on
Earth.
• Some types of organisms rely on the energy stored in
inorganic chemical compounds.
• Autotrophs (producers) use energy from the
environment to fuel assembly of simple compounds
into complex organic molecules.
Energy Flow
Autotrophs
• The best know autotrophs are those that harness the
power of the sun through photosynthesis (a.k.a.
plants) They use this energy to convert carbon
dioxide and water into oxygen and glucose.
• The second type of autotrophs use chemical energy
to make carbohydrates. This is performed by several
types of bacteria.
Energy Flow Consumers
• Heterotrophs (consumers) rely on other organisms for their
energy and food.
• Herbivores obtain energy by eating plants.
• Carnivores eat animals.
• Omnivores eat both plants and animals.
•
ex. Humans or bears
• Detritivores feed on the remains of plants,
animals and other dead matter.
ex. earthworms
• Decomposers breaks down organic matter.
fungus
• ex. Fungus or bacteria
• Scavenger- feeds upon dead material
•
ex. vulture
Feeding Relationships
• Energy flow through an ecosystem in one direction, from
the sun or inorganic compounds to autotrophs
(producers) and then to various heterotrophs
(consumers).
• Food Chains are a series of steps in which organisms
transfer energy by eating or being eaten.
• Food webs show the complex interactions within an
ecosystem.
• Each step in a food chain or web is called a trophic level.
Producers make up the first step, consumers make up
the higher levels.
Food Chain
Food Web
Ecological Pyramids
• An ecological pyramid is a diagram that shows the
relationship amounts of energy or matter contained
within each trophic level in a food web or food chain.
• Energy Pyramid only 10% of the energy available
within one trophic level is transferred to organisms
at the next trophic level ( a lot of energy is used for
metabolism of food and is given off as heat as well so
it is not available to pass on to the next energy level
Energy pyramid
Pyramids Continued
• Biomass pyramids show the total amount of living
tissue available at each trophic level. This shows the
amount of tissue available for the next trophic level.
• Numbers pyramid shows the number of species at
each trophic level.
• Because each trophic level harvests only about one
tenth of the energy from the level below, it can
support only about one 10th the amount of living
tissue.
Biomass pyramid
Cycles of Matter
• Unlike the one-way flow of energy, matter is
recycled within and between ecosystems.
• These cycles are the water cycle, Nutrient
Cycle, Carbon Cycle, nitrogen cycle and
phosphorus cycle.