Ecology
12.1
Learning Targets
• I can identify ways that organisms interact
with other organisms and non-living things
• I can describe feeding relationships among
organisms in a community
• I can explain how energy flows through
ecosystems
• I can identify materials that cycle through
ecosystems
Ecosystems
Ecosystems
Living Things
Populations
Communities
Non-living Things
Energy
Materials
How do Organisms interact?
• All organisms interact with one another and nonliving things in their environment
• Ecology is the study of the interactions among
living things and non-living things in their
environment
• Examples:
• 1. Animals interact with the air when they inhale oxygen and
exhale carbon dioxide
• 2. Animals interact with plants when they eat fruit or vegetables
Levels of Organization
Biosphere
Ecosystem
Community
Population
Organism
Levels of Interaction
• Life on Earth is organized into levels
• The higher the level, the more interactions there are
• To interact means to act upon or influence something
• ORGANISM
• The lowest level of organization is the individual
organism
• The place where an organism lives is called its habitat
• Each organism is adapted to live in its habitat
Population
• A group of organisms of the same species that
live in the same area form a population
• The individual members of a population interact
with one another
• Examples of interactions: Mating and competing
for food, water and space
Community
• Populations of different species that live in the
same area make up a community
• Bears, rabbits, pine trees and grass are different
populations of organisms, but may live together
in the same forest community
• Populations in a community interact with one
another in many ways
Ecosystem
• All the interactions among populations of a
community and the non-living things in their
environment make up an ecosystem
• Ecosystems occur on land, in water, and in the air
• As the community (living and non-living) of an
ecosystem interacts, they may cause changes to
the community
Changes in an Ecosystem
• Changes in the community may result in a
completely different type of community
• These changes over long periods of time are known
as succession
• Eventually, a community reaches a point at which it
changes little over time
• A community that is stable is called a climax
community
Effects of Pollution on
Ecosystems
• Pollution is anything added to the environment
that is harmful to living organisms
• Pollution is most often caused by human activity
• Activities that cause pollution:
• -burning coal, oil, gas
-acid rain (sulfur)
• -construction
-fertilizers
• -chemicals dumped by factories
Biomes
• Some ecosystems are found over large
geographic areas
• These are called Biomes
• Different biomes are found in different climates
(temperature, sunlight, rainfall)
• Examples of biomes: desert, rain forest, tundra,
grassland, forest
The Biosphere
• The highest level of organization is the Biosphere
• All the biomes on Earth together form the
biosphere
• The biosphere includes all organisms living on
Earth’s surface, in the water, underground and
in the air
• The biosphere also includes non-living things,
such as water, minerals and air
Vocabulary
• Ecology
• Habitat
• Climax Community
• Biome
• Self-Check Questions 1-5 pg. 267
• COMPLETE SENTENCES
Food Chains and
Food Webs
12.2
Food Chains vs. Food Webs
• Plant
Small Fish
Larger Fish
• This feeding order is called a Food Chain
• Almost all food chains begin with plants
Bird
• All the food chains in a community that are linked to
each other are called Food Webs
• Most organisms eat a variety of food sources
• Food chains are linked to one another at certain points
• Together, the food chains form food webs (pg. 272)
Producers
• Organisms that make their own food
• Every food chain begins with a producer
• Most producers use the energy of sunlight to
make food by the process of photosynthesis
Consumers
• Organisms that feed on or eat other organisms
are consumers
• All animals and fungi and some bacteria are
consumers
• Consumers can be:
• Herbivores – plant eating only
• Carnivores – meat eating only
• Omnivores – plant and meat eating
Feeding Order of Consumers
• First-order consumers eat plants (ex. rabbit)
• Second-order consumers eat animals that eat
plants (ex. snake eats rabbit)
• Third-order consumer eats animals that eat
animals (ex. hawk eats snake)
Pyramid of Numbers
• The pyramid is organized in order of consumers
and producers
• It begins with a producer at the bottom (grass)
• The highest level of consumer is at the top
• The size of the population decreases at each
higher level of a food chain (pg. 271)
Decomposers
• Decomposers continue the food chain by feeding
on a dead organism
• Decomposers feed on dead organisms at every
level of the pyramid (both producer and
consumer)
• Decomposers get food by breaking down
complex chemicals in dead organisms into simple
chemicals
• The chemicals become part of the soil and plants
take in these chemicals to help them grow
Vocabulary
• Consumer
• Producer
• Food Chain
• Food Web
• Self-Check Questions 1-5 pg. 273
• COMPLETE SENTENCES
How does Energy
flow through
Ecosystems?
12.3
How does Energy flow through
Ecosystems?
•
•
•
•
Plants use energy from the sun to make food
You get energy from the food you eat
Energy is the ability to do work
Energy comes in many forms
• Light and heat from the sun
• Electricity
• Batteries store chemical energy
• A moving bicycle has mechanical energy
• All living organisms need energy to live
Energy in Food
• Plants make their own food through photosynthesis
• Photosynthesis creates energy that the plant stores
in sugar molecules
• When the plant needs energy, to grow or reproduce,
it releases the stored energy
• When you eat potatoes, asparagus, or other plant
parts, you are taking in the plants’ stored energy
Flow of Energy Through Food
Chains
• The flow of energy in a food chain begins with the
producer, such as grass or other plants
• The energy stored in plants is passed on to the organisms
that eat the plants
• These first-order consumers use some of the food energy
and lose some energy in the form of heat
• The rest is stored as chemical energy in the first-order
consumer
Energy Pyramid
• The energy stored in first-consumers is passed on to
second-order consumers and so on
• The most energy is available to the producers; it comes
directly from the sun
• The amount of available energy decreases at each higher
level of a food chain (pg. 277)
• This is due to the consumers using energy for their own
needs and losing some energy in the form of heat
Importance of Sun
• Without the sun, there would be no life on Earth
• All plants and animals and most other organisms depend
on energy from the sun
• Energy flows from the sun to producers (plants)
• Some of that stored energy flows to consumers while
some is lost to the environment (heat)
• The sun continuously replaces lost energy
Vocabulary
• Energy Pyramid
• Self Check Questions 1-5 pg. 278
• COMPLETE SENTENCES
How do Materials
cycle through
Ecosystems?
12.4
Materials
• If a material exists naturally in the Earth, its
supply can eventually run out if over used
• Materials must be recycled and used again
• Some chemicals important for life are:
• Water
• Carbon
Oxygen
Nitrogen
The Water Cycle