ecology the study of interactions among organisms and between organisms and their environment
TRANSCRIPT
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