Energy Flow in an Ecosystem

What is an Ecosystem? An ecological system

consists of a living community and all of the physical aspects of its habitat

physical factors are known as abiotic factors and can include:▪ light, temperature, precipitation, soil type,

water availability, soil and water pH, etc the members of the living community are

known as the biotic factors in an ecosystem include organism like animals, plants,

mushrooms, and bacteria

Ecosystems and Energy

Ecosystems rely on energy -The amount of energy available

in an ecosystem determines how many organisms can live in that ecosystem

Energy Source

How does energy enter an ecosystem?

- Sunlight is the primary source of energy for most ecosystems on earth

No sun = No energy No Energy = No Life

No Life = BUMMER!

Biotic Factors – the Living Part of the Ecosystem

Divided into Trophic (feeding) levels. Primary producers/autotrophs Primary consumers/herbivores-plant

eaters Secondary consumers/carnivores –meat

eaters Tertiary consumers/carnivores Detritivores/decomposers- vital part of

the ecosystem. They recycle abiotic materials from dead organisms – without them, life would stop.

- they play a role in nutrient cycling

What are Primary Producers?

Primary producers are the first producers of energy rich compounds that are later used by organisms

Autotrophs: “self feeders”, organisms that can capture energy from nonliving sources and convert it into forms that living cells can use

Example: plants obtain energy from sunlight and turns it into nutrients that can be eaten and used for energy by animals such as a caterpillar

Energy Enters an Ecosytem

Sunlight needs to be converted to be used in an ecosystem.

Who converts the sunlight? - plants, algae, some bacteria - organisms that convert the energy

from sunlight into a useable form are known as producers

- How do they do convert the energy? Photosynthesis

Photosynthesis

Why is it important? traps the sun’s energy and stores it in a

sugar called glucose. The stored energy is used by living

things

Photosynthesis Equation

6 CO2 + 6 H2O + Energy C6H12O6

+ 6 O2Carbon Water Sunlight

Glucose OxygenDioxide

Who uses Energy?

Who uses the energy trapped by producers? All living things use the energy

trapped by producers producers use this energy themselves Other living things, called consumers

eat producers for their energy

Life without light

Chemosynthesis: chemical energy is used to produce carbohydrates

Primary producers like bacteria harness chemical energy from inorganic molecules such as hydrogen sulfide

(hydrogen sulfide-bacterial breakdown of organic matter in the absence of oxygen)

Consumers

Herbivore- plant eaterCarnivore- animal eaterOmnivore- eats both plants and

animalsDecomposers- decay, chemical

breakdown of organic matter Scavengers- animals that consume

the carcasses of other animals that have been killed

Detritivores- digest decomposers

Energy Pyramid

Primary Consumers

Producers

Detritus Feeders

Producers

Primary Consumers

Secondary Consumers

Tertiary Consumers

Decomposers

Energy Pyramid

Food Chains

Food Chain – the path of

energy through the trophic levels of an ecosystem

- all food chains begin

with a producer

Food Web = a series of multiple interconnected food

chains. in most ecosystems,

energy doesn’t follow a simple

path many consumers eat at

different trophic levels food webs are

representation of the complex relationships

between organisms in an

ecosystem

Food Web

Vocabulary Review

Biomagnification – the concentration of toxins as they move through a food chain.

Ecological succession – changes in the composition of species found in a community over time

Ecosystem – a community interacting with its environment through a one-way flow of energy and the cycling of materials

Ecosystem stability – the ability of an ecosystem to return to a state of equilibrium following a disturbance

Vocabulary Review

Ecological pyramids: models that show the relative amount of energy or matter contained within each trophic level

Symbiosis – an ecological interaction between two organisms

Trophic level – position that organism(s) occupy in a food web, which is defined by its relationship to the primary energy source

Pioneer species – first species to populate an area during succession

Vocabulary- review

Ecological succession: a series of more or less predictable evens that occur in a community over time

Primary succession: begins in areas that have no remnants of an older community

Secondary succession: parts of old community survive, and can regrow rapidly

Ecological Pyramid

90% of the energy available is lost as energy is transferred to the next trophic level - the energy is lost as heat Only 10% is of passed on to the next level

100,000 J of sunlight

100 J Rats

10 J Snakes

1,000 J Grasshoppers

10,000 J wheat

Ecological Pyramid of energy

Pyramids of energy show the relative amount of energy available at each trophic level of a food chain or food web

Only 10% of energy is transferred to the next level

Biomass

Is the total amount of matter in the form of living tissue within a given trophic level

The amount of biomass a given trophic level can support is determined by the amount of energy available

Pyramid of Biomass

A pyramid of biomass is a model that illustrates the relative amount of living organic matter available at each trophic level in an ecosystem.

Trophic Level: Producers

Autotrophs (producers) ▪ Algae▪ Phytoplankton▪ Plants▪ Cyanobacteria▪ Mosses▪ Some protozoa

Trophic Level: Consumers

Heterotrophs (consumers) ▪ Primary▪ Secondary▪ Tertiary▪ Herbivores▪ Carnivores▪ Omnivores

Trophic Level: Decomposers

Decomposers ▪ Fungi▪ Protists▪ Bacteria

Trophic Level: Detritivors Detritivores (detrivores)

▪ Millipedes▪ Wood lice▪ Types of earthworms

Discussion

What happens to the biomass and numbers as we move up trophic levels?

How does energy move through an ecosystem?

What amount of energy is available to each trophic level?