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Ecology
Introduction to Ecology
• Ecology is the study of organisms and their interactions with their environment.
• The environment includes 2 types of factors:– Biotic factors – the living parts of the environment• Plants, animals, bacteria, fungi, protists
– Abiotic factors – the nonliving parts of the environment• Water, oxygen, light, temperature, etc.
Levels of Organizationorganism
population
community
ecosystem
biome
biosphere
The Importance of Abiotic Factors• Not every organism can live everywhere on Earth• Abiotic factors determine which organisms can survive
where:– Temperature – effect on body temperature– Water – too much/not enough water– Light – availability for photosynthetic organisms– Wind – amplifies effects of temperature– Rocks/Soil – which organisms can live with/on them, based on
pH and mineral composition– Periodic Disturbances – catastrophes, such as tornadoes, fires,
tsunamis, etc.
Biomes
• A group of ecosystems that have similar climates and communities
• Aquatic (dominant)• Terrestrial– Tundra, Taiga, Tropical Forest, Savanna, Chaparral,
Desert, Temperate Grassland, Temperate Deciduous Forest
Interactions between organisms and their environment limit the distribution of species
What did you eat for dinner last night?
Food Chain• A linear relationship that shows
who eats whom in an ecosystem.
Food Web• A network of feeding interactions
in an ecosystem
Trophic Level• Each step in a food chain or
food web.
Ecological Pyramids• Show the relative amount of
energy or mater in each trophic level
Pyramid of Energy• Only 10% of the energy at one trophic
level is transferred to the next level.
Pyramid of Numbers
Pyramid of Biomass• The total amount of living tissue
in a trophic level
10% Rule• Only 10% of the energy at one
trophic level is transferred to the next trophic level. Only 10% of the energy is used
to build Biomass (what will be eaten)
Energy Flows Matter Cycles
• 10% Rule because Energy is lost from an Ecosystem
(heat, life processes)• Nutrients (matter) NOT lost - Recycled
Within a community, matter moves through the food chain.
How do living organisms interact?
Niche – my place in the World
1. What do I eat? How do I collect my food? Where do I collect my food?When do I collect my food?
2. Where do I live? - Habitat
3. Where and how do I raise my young?
4. Do I sleep, how long, when, where?
5. Do I like it cold or warm; humid or dry, land or water?
Niche – My place in the Ecosystem
How I live, not simply where I live
How I contribute to the energy flow in my ecosystem
My Niche – Your Niche
Competitive Exclusion
Elimination of a competing species: Species using resources more efficiently will eliminate the other
How can we peacefully co-exist
My Niche and Your Niche do not overlap too much
No two species can occupyThe SAME Niche!
Dividing Resources Among Species:
Warbler species - all five species feed on insects in the same trees at the same times as each other –Fundamental Niche is the same.
They do not have overlapping Niches - they occupy different parts of the tree!
Realized Niche
Cape May Warblers can feed on insects all over a Spruce Tree, but they stay mainly at the top. Remaining portions of the Spruce are divided among its potential competitors – Realized Niche is different for the 5 species of Warbler!
2. Keystone Species
• Changes in the population of a single species can cause dramatic changes in the community structure.• Remember the WOLVES in Yellowstone Park
Symbiosis- a relationship in which two species live closely together
1. Mutualism- relationship in which both species benefit ex. Pollinationmutual benefit
2. Parasitism- one individual lives inside or on a host and harms it
3. Commensalism- one species benefits and the other is not affected
Mimicry- a harmless species resembles a poisonous or distasteful species
How can we peacefully co-exist
My more resourceful competitor will not eliminate me - I have a predator on my side.
Predation can keep the number of a species low so that competition is reduced.
Result: Increased Biodiversity
Why is an Ecosystem with greater Biodiversity more stable than one with fewer species?
How do we interact with our Environment?
Grade earned: F
• The variety of organisms in a given area• One of Earth’s greatest natural
resources!• The more biodiversity, the more
healthy, complex and stable an ecosystem is.
Biodiversity
The ability of a community to respond to changes in its environment (its “resilience”) is directly related to its genetic diversity.
Populations and Communities with the least genetic diversity are most at risk for extinction in an ecosystem.
Why? Can’t adapt to changes in the environment.
• Succession- the gradual, sequential growth of a species in an area
Nature increases diversity through
• Occurs in an area where there was no previous life• Examples: Bare rock, island, sand dune• Pioneer Species-first to colonize
1. Primary Succession
• Follows after disruption of an area• Occurs faster than primary succession• Examples: Fire, Flood, Volcanoes, Humans
2. Secondary Succession
• Diversity Index = # of Species # of organisms• The closer to 1 the diversity index is,
the more diverse and healthy the habitat
How do we measure biodiversity?
• The total area of functioning land and water ecosystems needed both to provide the resources an individual or population uses and to absorb and make harmless the wastes that individual or population generates
Ecological Footprints
Human Impact has contributed to the extinction of many species.
Human activity impacts ecosystems locally, regionally, and globally.Habitat Destruction is a major human impact.
What do you think Your House was build on?
Homework Assignment: • Go to http://
www.earthday.org/footprint-calculator and determine your personal ecological footprint.
• Print out the last page showing results.
Ecological Footprint
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