Ecology Notes – Part 1:Principles of Ecology

Ecology - The study of the interactions of organisms with one another and their physical environment

The multiple levels of biological systems

The multiple levels of biological systems

organism – an individual living thingex) a black bat

population – all of the individuals of a species that live in the same area

ex) the black bats

The multiple levels ofbiological systems

Community – a group of different species that live together in one areaex) the black bats, worms, moss, mushrooms, bacteria, and beetles living in the cave

Habitat – place where an organism usually livesex) a cave is a habitat for a black bat

The multiple levels ofbiological systems

ecosystem – the different species (community) plus the environment (soil, water, weather); biotic factors + abiotic factors

ex) soil in the bottom of the cave, light entering the cave, temperature in the cave, humidity in the cave, plus the community

biome – major regional or global community of organisms characterized by the climate conditions and the plant communities that thrive there

Vocabulary Quizmatch the phrase to the correct word

• community• ecosystem• population• organism• biome• habitat

1. fish, snails, & plants that live in a stream

2. a large group of zebras3. tropical rainforest4. rocks, water, mice,

deer, oak trees5. one mockingbird

Biotic & Abiotic Factors

biotic factors – are organisms in a habitat

ex) animals, plants, fungi, protists, bacteria

abiotic factors – are the physical aspects of a habitat” ex) wind, water, rocks, sunlight, shade, etc.

What abiotic factors do you see here?What biotic factors do you see?

Ecosystems are complex. Changes to the biotic OR abiotic factors in an ecosystem affect all species. biodiversity – the assortment or

variety of living things in an ecosystem

biodiversity is threatened by human activity– pollution– global warming– habitat destruction

Biotic and Abiotic Factors keystone species – a species that

has an unusually large effect on its ecosystem

ex) sea otter – has a tremendous effect on the ecosystem it is a part of

sea otters eat sea urchins, which keeps the sea urchin

population under control

Biotic and Abiotic Factorskeystone species continued when the sea otter population

is over-hunted, there are not enough otters to eat the sea urchins

the sea urchins, in turn, eat too much kelp (an aquatic plant, like seaweed) from kelp beds and the kelp population declines

without kelp beds, fish have no place to lay their eggs, so the fish population declines; when hunters stop hunting the sea otter population, the urchin populations decrease and the kelp beds and fish populations go back to normal

Food Chains and Food Webs

Producers provide energy for other organisms in an ecosystem

producer – organism that obtains energy from nonliving resources; organism that makes its own food basis for ecosystem’s energy most rely on sunlight

almost all producers obtain energy from sunlight most producers use sunlight as their energy source photosynthesis – 2-stage process that green plants and

algae use to produce energy

6CO2 + 6H2O C6H12O6 + 6O2

(SUNLIGHT)

Food Chains and Food Webs

autotroph – another word for producer; word parts: self feeder

consumer – organism that gets its energy by eating other living or once-living resources, such as plants and animals; connected to producers through energy, which ultimately comes from the sun

heterotroph – another word for consumer; word parts: different feeder

Label the organisms below as producer, autotroph, consumer, heterotroph (use all words that apply)

Food Chains and Food Webs

producer,autotroph

consumer,heterotroph

consumer,heterotroph

producer,autotroph

Types of Consumers herbivores – organisms that eat only plants; ex) rabbit carnivores – organisms that eat only animals;

ex) snake omnivores – organisms that eat both plants and

animals; ex) chicken (eats seeds and insects) detritivores – organisms that eat dead, organic matter;

ex) millipede decomposers – organisms that break down organic

matter into simpler compounds; ex) fungi and bacteria responsible for the last step in every food chain,

returning nutrients to the environment receive energy from every other level

A food chain is a model that shows a sequence of feeding relationships

***Energy FLOWS through ecosystems***• food chain – sequence that links species by

their feeding relationships• note that the arrows that

link one organism to another show the direction that energy is flowing; energy flows from the organism being eaten to the organism doing the eating

Draw the arrows to complete the food chain below:

Hawk

Trophic Levels• trophic levels – levels of nourishment in a food

chain; ex) producer herbivore carnivore represents a food chain with 3 trophic levels

• energy flows up the food chain from the lowest trophic level to the highest– producer – autotrophs – level 1

– primary consumer (1̊% ) – herbivores & omnivores – level 2

– secondary consumer ( 2̊% ) – carnivores & omnivore – level 3

– tertiary consumer (3̊% ) – carnivores that eat carnivores, and some omnivores – level 4

Trophic Levels

secondaryconsumers

tertiaryconsumers

primaryconsumers

producers

A food web shows a complex network of feeding

relationships

• food web – model that shows the complex network of feeding relationships and the flow of energy within and sometimes beyond an ecosystem─ at each link, some energy

is stored in the organism and some energy is dissipated (lost) to the environment

─ stability depends on the base – the producers (plants, algae, phytoplankton, some bacteria)

marine food webs show multiple

trophic levels and food chains

Don’t forget about the online textbook resources like “Build a Food Web”

Pyramid Models

• An energy pyramid shows the distribution of energy among trophic levels– energy in ecosystems

comes from sunlight– energy flows UP the food

chain from producer to consumer

– some energy is lost from the ecosystem, mostly as heat

– each level of a food chain contains less useful energy than the level below it

Pyramid Models

10%

10%

10%

Loss of Available Energy

• biomass – measure of the total dry mass of organisms in a given area

– incorporated into the body of a consumer

– up to 90% of the energy stored in the eaten organism may be lost as heat (energy)

Energy Pyramids– the longer a food chain, the more energy lost

• energy pyramid – diagram that compares energy used by producers, primary consumers, and other trophic levels– illustrates how available energy is distributed

among trophic levels in an ecosystem– energy is measured in kilocalories (kcal)

Label the correct amount of energy at each trophic level:

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End of Part 1