EcologyThe study of interactions among

organisms and between organisms and their environment

Ecology Focus ? How do organisms contribute to the

functioning of the environment as a system?

How is energy captured, stored, and transferred in an ecosystem?

What specific impacts do humans have on the environment?

Abiotic – Nonliving factors of an ecosystem Climate, land conditions, etc.

Biotic Living factors of an ecosystem Plants, animals, fungi, etc

Hierarchy of Life Complexity & levels of organization:

Species / Organism Population Community Ecosystem / Biome Biosphere

Energy Transfer through an Ecosystem

All organisms need energy to carry out their life functions: growth, movement, reproduction, etc.

Energy flows through the TROPHIC Levels of a Food Chain

Sun - primary source of energy to the to the

Producer (autotrophs)– capture sunlight & convert it to a usable form (plant material)

to the heterotrophs

Primary Consumers – feed on producers to the

Secondary Consumers – feed on primary consumers

Energy Flows through each Trophic Level or Step of the Food Chain

Food Web- a more accurate model of the complex network of feeding relationships among the various organisms in an ecosystem

Pyramid Models

Energy Transfer through Trophic Levels is NOT 100% efficient

Pyramid of Energy Transfer

10% Efficient transfer at each level

Biomass organic matter in an ecosystem Gross Primary Productivity

Rate at which producers capture energy

Net Primary Productivity Rate of biomass accumulation into plant

material photosynthesis – respiration in plants

Varies by light, temperature, precipitation, availability of nutrients

Pyramid of Biomass Approximate dry weight of

biomass at each level

Pyramid of Numbers Approximate number of

organisms supported at each level

Ecosystem Recycling

Water, Carbon,and Nitrogen Travel

Through a Biogeochemical Cycle to be recycled and reused

The Law of Conservation of Matter & Energy

Matter and energy are neither created nor destroyed but only

change in form

The Water Cycle

New terms you should know… Precipitation –water vapor converting to

liquid. Ex: Rain, snow, sleet, hail, fog Evaporation – liquid water converting to water

vapor in the atmosphere

Transpiration – releasing of water by plants into the atmosphere

The Carbon Cycle

Decomposition—the release of CO2 from the

breakdown of dead matter

Fossil Fuels—decaying remains of living things containing carbon that after years of heat and pressure that release CO2 when burned

New terms you should know…

The Nitrogen Cycle

Nitrogen fixation—conversion of atmospheric nitrogen by bacteria into a nitrogen containing compound that can be used by plants and animals

Excretion—nitrogen containing animal waste that is absorbed by soil

Decomposition—breakdown of dead organisms which add nitrogen to the soil

Denitrification—conversion of nitrogen trapped in the soil and dead animals back into atmospheric nitrogen

New terms you should know…

The Dynamics of Communities

What is a Community?

A collection of interacting populations

A groups of various species living in the same area at the same time

Communities Need Homeostasis

State of equilibrium

Stable communities require: constant source of usable energy organic and inorganic materials must be

recycled constantly

Symbiosis A close relationship between

two organisms

Examples: Mutualism Commensalisms Parasitism

Mutualism Both organisms benefit

Examples: Butterflies & flowers

food pollination

Commensalisms One organism benefits Other organism is relatively

unaffected

Examples: barnacles attached to whales

Parasitism One organism benefits Other organism is harmed

Examples: fleas and mammals viruses pathogenic bacteria round worm

Predator & Prey One member kills and eats another

One benefits while the other is harmed (in the short term!!!)

But one may adapt to the pressure of predation

Predator & Prey Pattern

Preventing Predation Camouflage Warning color Mimicry

Succession:natural changes in a community over

timeExamples:

increase in:--population

--biomass --productivity

Pioneer Species

First species in new community:

Reproduce Rapidly SmallSurvive harsh conditions

Example: Lichen

Pioneer Forest

Changes Continue Until

Homeostasis is reached: Called Climax Community:

Stable and mature At equilibrium

Climax Community

2 Types of Succession

Type 1: Primary Creating a NEW Community

Example / Causes:Volcanic eruptionsClearing of Glaciers

Primary Succession

Type 2: Secondary Regrowth of a Previous Existing

Community Examples / Causes:

Natural Disastershurricanesforest fires

Human ActivitiesAbandoned farmlandConstruction / real estate

Example: Forest Fire

Yellow-stone National Park

1988: Bunson Peak and the area around it was scorched by the North Fork fire, but has recovered nicely.

1998

Secondary Succession

Secondary Succession

Secondary Succession

Population Patterns

Limiting Factors in a Community

Any biotic or abiotic factor that limits growth of a population

Restrictions on populations: Coexistence of other populations Size / Numbers Reproduction Distribution

Examples of Limiting Factors depletion of resources like food, water &

shelter

appearance of predators, parasites, & disease

natural disasters such as fire, flood, and drought

Carrying Capacity

stabilizing of population growth due to limiting factors

Density-Dependent Factor Limiting factors that depend on or response

to an increase or decrease in population size

Examples: Food Water Shelter predators

Density-Independent Factor Not affected by population size

Have the same affect on the population with many or few members

Examples: Fire Drought

Distribution Patterns Patterns of organisms in a population

Location of each organism in a populations

Types of Distribution Random Clumped Uniform

Random Organisms are located in NO order / pattern

Habitat has abundant resources throughout

Clumped Organisms are grouped together in various locations

Habitat resources are located only is certain areas

Uniformed Organisms are found at roughly equal

distance from each other

Resources equally spread throughout the habitat (typically man-made)

3 Age Structure Diagrams of population patterns over time

Population drastically

increases over time

Examples:

Population do NOT increase or decreasesExamples:

Population drastically decreases over timeExamples:

Organisms and their Environment

Habitat the environment in which an

organism lives or grows

Niche The functional ROLE a species

plays in its community depends on:

WHERE an organism lives AND

WHAT it does & need for survival

Competition two organisms striving for the

same resource

no one obtains 100% of the resources, so they are all negatively affected

2 Results of Competition and Niche Overlap

One species will NOT survive

OR Species must change to reduce

overlap

Competitive Exclusion Principle

Competition for the same limiting resource will eliminate the weaker species

Therefore…. No two organisms can

have 100% identical niches use the same resource, at the same time, in the same place

So, fundamental niche is reduced to realized niche

Fundamental vs.

Realized ???

Fundamental Niche the potential ability of a

species to receive all possible resources

Realized Nichethe resources that the

species actually uses

Example: Warbler Birds

Warbler Bird Example: Fundamental niche –

each warbler bird is capable of inhabiting the whole tree

Realized niche – each bird limits their habitat to a portion of the tree

to: reduce niche overlap reduce competition

Fundamental niche is reduced to realized niche to ensure coexist survival