Ecology: : the study of interactions that the study of interactions that take place between organisms and their take place between organisms and their environmentenvironment

Principles of Ecology

You will describe ecology and the work of ecologists.

You will identify important aspects of an organism’s environment

You will trace the flow of energy and nutrients in the living and nonliving worlds.

Organisms and their Environment

Section Objectives:Section Objectives: Distinguish between the biotic and abiotic Distinguish between the biotic and abiotic

factors in the environmentfactors in the environment Compare the different levels of biological Compare the different levels of biological

organization and living relationships important organization and living relationships important in ecologyin ecology

Explain the difference between a niche and a Explain the difference between a niche and a habitat.habitat.

BiosphereBiosphere

the portion of Earth that the portion of Earth that supports living things.supports living things.

Living things are affected Living things are affected by both the physical or by both the physical or nonliving environment nonliving environment and by other living and by other living things.things.

Abiotic and BAbiotic and Biotic factorsiotic factors

Abiotic factors Abiotic factors ~ The nonliving parts of an organism’s ~ The nonliving parts of an organism’s environmentenvironment

Examples: air currents, temperature, moisture, light, Examples: air currents, temperature, moisture, light, and soil.and soil.

often determine which species survive in a particular often determine which species survive in a particular environmentenvironment

biotic factors biotic factors ~ All the living organisms that inhabit an ~ All the living organisms that inhabit an environment environment

All organisms depend on others directly or indirectly for All organisms depend on others directly or indirectly for food, shelter, reproduction or protectionfood, shelter, reproduction or protection

Levels of OrganizationLevels of Organization

1. Organism~ An An individual living thing individual living thing that is made of cells, that is made of cells, uses energy, uses energy, reproduces, responds, reproduces, responds, grows, and developsgrows, and develops

22. Population ~. Population ~ a group of a group of organisms, all of the organisms, all of the same species, which same species, which interbreed and live in the interbreed and live in the same area at the same same area at the same time; competition occurstime; competition occurs

Levels of Organization IILevels of Organization II

3. Biological community3. Biological community~~made made up of interacting populations up of interacting populations in a certain area at a certain in a certain area at a certain time.time.

~~A change in one population in a A change in one population in a community may cause changes community may cause changes in the other populations.in the other populations.

44. . Ecosystem ~ Populations of Populations of plants and animals that plants and animals that interact with each other in a interact with each other in a given area and with the given area and with the abiotic components of that abiotic components of that area.area.

Organisms in EcosystemsOrganisms in Ecosystems A A habitat habitat is the place where an is the place where an

organism lives out its life.organism lives out its life. ~ ~ Habitats can change due to Habitats can change due to

both natural and human both natural and human causescauses

nicheniche is the role or position a is the role or position a species has in its environmentspecies has in its environment—how it meets its specific —how it meets its specific needs for food and shelter, needs for food and shelter, how and where it survives, and how and where it survives, and where it reproduces in its where it reproduces in its environment.environment. ~~includes all its interactions includes all its interactions

with the biotic and abiotic with the biotic and abiotic parts of its habitat.parts of its habitat.

It is thought that two species It is thought that two species can’t exist for long in the same can’t exist for long in the same community if their niches are community if their niches are the same.the same.

SymbiosisSymbiosis

The relationship in which there is a close and The relationship in which there is a close and permanent association between organisms of permanent association between organisms of different species different species

Three kinds of symbiosis are: Three kinds of symbiosis are: mutualism, mutualism, commensalism, commensalism, andand parasitism. parasitism.

Symbiosis IISymbiosis II

1.Mutualism ~ both both species benefit species benefit

2. Commensalism ~one species benefits one species benefits and the other species is and the other species is neither harmed nor neither harmed nor benefited.benefited.

Symbiosis IIISymbiosis III

3. Parasitism ~ a a member of one species member of one species derives benefit at the derives benefit at the expense of another expense of another species (the host) :species (the host) :usually usually harm but don’t kill hostharm but don’t kill host

PredatorsPredators seek out and eat seek out and eat other organisms.other organisms.

animals that predators eat are animals that predators eat are called called prey.prey.

2.2: Nutrition and Energy Flow Section ObjectivesSection Objectives

• Compare how organisms satisfy their nutritional needs.

• Trace the path of energy and matter in an ecosystem.

How organisms obtain How organisms obtain energyenergy

The ultimate source of The ultimate source of the energy for life is the the energy for life is the sun.sun.

The producers: Autotrophs~ An An organism that uses light organism that uses light energy or energy stored energy or energy stored in chemical compounds in chemical compounds to make energy-rich to make energy-rich compounds (compounds (Plants-Plants-photosynthesisphotosynthesis

How organisms obtain How organisms obtain energy IIenergy II

The consumers: Heterotrophs ~ An An organism that cannot organism that cannot make its own food and make its own food and feeds on other feeds on other organisms organisms

depend on depend on autotrophsautotrophs for for nutrients and energy.nutrients and energy.

Heterotrophs display a variety Heterotrophs display a variety of feeding relationships.of feeding relationships.

Herbivore ~ Herbivore ~ feeds only feeds only on plantson plants

Carnivores ~ Carnivores ~ kill and eat kill and eat only other animals only other animals

Omnivores Omnivores ~eat both ~eat both plants & animals plants & animals

Heterotrophs display a variety Heterotrophs display a variety of feeding relationships.of feeding relationships.

IIII ScavengersScavengers eat animals that eat animals that

have already diedhave already died

DecomposersDecomposers break down the break down the complex compounds of dead complex compounds of dead and decaying plants and and decaying plants and animals into simpler animals into simpler molecules that can be more molecules that can be more easily absorbed. easily absorbed.

Flow of Matter and Flow of Matter and Energy in EcosystemsEnergy in Ecosystems

Food chains: the the stepwise flow of energy stepwise flow of energy and nutrients and nutrients through an through an ecosystem.ecosystem.

from plants (producersfrom plants (producers) ) to herbivores (primary to herbivores (primary

consumers) consumers) to carnivores (secondary to carnivores (secondary

and higher-level and higher-level consumersconsumers

berries → mice → black bear

Trophic levels represent links in the chain

Each organism in a food Each organism in a food chain represents a chain represents a feeding step, or feeding step, or trophic trophic levellevel, in the passage of , in the passage of energy and materials.energy and materials.

Food webs

network of network of interconnecting food interconnecting food chainschains It is a more realistic It is a more realistic

view of the trophic view of the trophic structure of an structure of an ecosystem than a ecosystem than a food chainfood chain

Energy and trophic levels: Ecological pyramids

show how energy flows show how energy flows through an ecosystem.through an ecosystem.

illustrates that the amount illustrates that the amount of available energy of available energy decreases at each decreases at each succeeding trophic level. succeeding trophic level.

The total energy transfer The total energy transfer from one trophic level to from one trophic level to the next is only about ten the next is only about ten percent because organisms percent because organisms fail to capture and eat all fail to capture and eat all the food energy available at the food energy available at the trophic level below the trophic level below them.them.

BiomassBiomass is the total weight is the total weight of living matter at each of living matter at each trophic leveltrophic level