Principles of Ecology

Crash Course on Ecology

Ecology: the study of how organisms interact with the living and _non-living_ things that surround them

Biotic- _living_ parts of the ecosystem

ex. bacteria, plants and animals

Abiotic- non-living parts of the environment

ex. soil, water, physical space and energy

Biosphere: all of the Earth's ecosystems from the bottom of the ocean to many miles up in the sky

Habitat: a _location_ where a particular organisms lives

ex. field, forests, streams, etc.

Niche: the _role_ that each species plays in the ecosystem

Only one animal can fill a niche at any point in time.


Types of Feeding Relationships

  • Autotroph- (producers) make their own food by _photosynthesis_ (plants)
  • Heterotroph- (consumers) must eat something to survive
    • Herbivores- eat _plants_
    • Carnivores- eat animals
    • Omnivores- eat _both_ plants and animals
      • Decomposers- break organisms down and return nutrients to the soil. They are the _recyclers_ in the ecosystem.
      • Scavengers- eat dead organisms that they did not _kill_ themselves.
      • Parasites- live off of another organism (host) and do not kill them usually.


Food chain: a series of organisms showing who eats what! Long chains begin with producers/autotrophs, followed by herbivores, then carnivores and ending with decomposers.

  • Arrows always go the direction of energy flow!

Food web: the complex _web_ of food interrelationships between plants and animals in the ecosystem. It is like interlocking food chains! Why is a food web more accurate than a food chain?

The SUN is the primary source of life energy on Earth.       

The Energy Pyramid  

Trophic levels form an Energy Pyramid
            Level 1: Autotroph/Producers= Plants
            Level 2: Herbivore
            Level 3: Carnivore

The biomass of each level of the energy pyramid is _90_% less than the one below it! Only _10_% of useable energy is transferred up to the next trophic level because so much is lost.


      1. Some of the food source many be _inedible_ or indigestible. (In which case decomposers would extract the last bit of energy from the dead organism)
      2. Energy may be expended catching the _prey_
      3. Energy is degraded through normal _metabolic_ processes

        A self sustaining ecosystem requires:

        1. A constant source of energy (the _sun_!)
        2. A process to capture and store sunlight (_photosynthesis by producers_)
        3. A way to recycle elements back into the ecosystem (decomposers)

        Matter is constantly recycled through the ecosystem by decomposers such as _bacteria, insects_ and fungi. This is called Decomposition. The raw material formed by the break down of wastes and dead bodies of organisms is recycled and reused by _decomposers_.


Wildlife Survival


Ecology of Populations:

  • the study of how populations interact with their environment

Biodiversity: is a measure of the _number_ of different species in an ecosystem. The more biodiverse an area, the more _stable_ it is.

ex. An insect eating a monoculture of corn versus an organic farm with _variety_ of different plants.

Population: a group of individuals of the _same_ species

Communities: two or more populations of _different_ species in the same area

Abundance is the number of _the same species_ in a population and Diversity is the number of _different_species in a community.

  • As you go farther North, the abundance of wildlife _increases_ while the biodiversity _decreases_
Population Growth
  • Biotic Potential- _maximum_ growth rate of a population given unlimited resources in the environment.
    • A female human can have up to _20_ children!!
  • Competition: the struggle for resources among organisms

Carrying Capacity- _maximum_ number of individuals a given environment can support

Limiting factor: the living and non-living things in the environment that limit population size

  • Know the major the limiting factors (any resource that is in short supply) that could influence the population size of a species. It could be biotic or abiotic
    • Examples: space, _temperature_, water (abiotic) or preditors and food (biotic).
  • Competition is the struggle for resources among organisms

Population curves

  • J-curve- unrestricted, _population_ growth. This spells trouble for the environment and the ultimate health of the population because of course nothing can grow forever.
    • Have you seen human population growth curve? It looks exactly like a _S_-curve!!!!
  • S-curve- arithmetic growth. The growth rate is _slower_ as the size of the population approaches the carrying capacity and the population eventually becomes _stable_.
  • Predator Prey Oscillation Curve. The growth curves oscillate slightly out of synch.


Relationships and Biodiversity State Lab


Symbiosis- a relationship between two or more species

Mutualism- both members of the partnership _benefit_. 

Commensalism- one organisms clearly _benefits_ and the other is neither benefited nor harmed.

Rhinosaurus and cattle egrets
Shark and remora
Oak trees and Spanish moss

Parasitism- the parasite benefits at the expense of the _host_.

Tropical Round worms and Ms. Law

Neutralism- _neither_ party benefits or is harmed

Bison and Sunday School Teacher



Ecological Succession

Crash Course on Ecological Succession

Ecological succession is the process by which organisms occupy a site and gradually change it after many years causing the habitats to become more complex.

Primary Succession- occurs when a community begins to develop on a site previously _unoccupied_ by living organisms such as an island or new volcanic flow

    Pioneer species- in primary succession, the species that _first_ colonizes the new area
    -often microbes, mosses and lichens   

    A typical primary ecological succession in NY is:

    Lichen and _Moss_- Grasses- Shrubs- Small Trees- Hardwood Trees

Secondary Succession- occurs when an _established_ community is disrupted and a new one subsequently _grows_ at the site.

Disruption may be caused by natural catastrophe or human activity

Aquatic Succession- succession taking place in a body of _body_

Typically a pond will develop by:

Pond (plants and animals die over time)- Sediment builds- Pond gets shallow-Swamp develops-_Open_ Field-Forest



Ecology Part 2

HUMAN IMPACT on the Environment (Spoiler alert- its not good)

Crash Course on Human Impact on the Environment

Material Cycles:

1. Carbon/ ________ Cycle (Photosynthesis/ Respiration)
2. Water Cycle (Evaporation, Transpiration, Condensation, ___________)
3. Nitrogen Cycle (____, nitrogen fixing bacteria, plants, animals, waste)

Biodiversity is a measurement of the degree to which species vary within an ecosystem.

The more species present in an ecosystem the _______ the biodiversity.
** As biodiversity increases, the stability of an ecosystem __________.

How man has affected biodiversity

1. Cutting down _______ (for wood)
2. Monoculture: Planting all of the _______ crop in an area (loss of biodiversity)
3. Removed vegetation for houses, parking lots, roads, etc.
4. Killed organisms and destroyed the food ______ (because all organisms are linked to
one another in one way or another)

Renewable Resources - resources that can _________ themselves if not abused (ex. planting of trees)

Nonrenewable Resources - resources that take a ______ time to replace or form (like coal, oil)

The Solution: Preserving our resources:

1. Reduce - cut ________ on the amount used (smaller packaging)
2. Reuse - use it for ___________ application (old water jugs as raft float)
3. Recycle - can be used to make the product again (like glass _________)

Human Activities and the Loss of Diversity: (This can create endangered species as well)


1. Habitat Destruction- destroying the natural environment through cutting down _________, etc.
2. Invasive species from _________ habitat- example: purple loosestrife; zebra mussels; dandelions
3. Pollution- a harmful change in the __________ make up of the air, soil and water.
4. Population- the incredible population _________ of humans has stressed the Earth's health
5. Over harvesting- the depletion (Endangerment) or loss (Extinction) of a species by over ________.

Impact of technology and industrialization:

1. Industrialization- increases pollution of air and water- uses more energy, water, fossil and nuclear fuels.
2. Water pollution- from human and livestock _________, wastes from homes and factories
3. Toxic wastes- DDT, spent nuclear fuel, mercury
4. Thermal pollution- heat pollution such as from ________ power plants
5. Air pollution- burning fossil fuels is very polluting to the air- it creates both _______ Rain and Global _________.

Acid Rain- Sulfur and nitrogen from factories and car _________ combine with water vapor to form rain with a low pH (acidic). Acid rain kills trees, aquatic animals and destroys historical artifacts.

pH scale: 14 ----- basic ----- 7 ----- acid ----- 0

Global Warming - an increase in the earth’s temperature is caused by an increase the amounts of ______ in the atmosphere. Burning fossil fuels for energy emits carbon dioxide. This is causing glaciers to melt, sea levels to ______, species extinction and massive changes in weather patterns (storm are more massive and droughts more severe).

Ozone Depletion- a hole in ozone layer in the stratosphere is caused by use of _______'s. **Ozone acts as a sun block for all organisms on the earth!!! UV light causes _____ cancer and cataracts.


Some Positive Influences of Humans on the Ecosystem (we all can make a difference)

  • Sustaining endangered species by using habitat protection methods such as wildlife ______ and national parks. (Keep some of your property wild!)
  • Passing wildlife management laws such as hunting restrictions. (Don't eat ______ that are unsustainably harvested)
  • Adding ______ to Adirondack lakes in an effort to neutralize their acid pollution so the original living things in these lakes can be reintroduced. (Or car pool so you don't create as much acid rain).
  • Design new products which meet basic needs without generating _______. (Buy from Green Businesses)
  • Inspection of all materials before entering the country to prevent pest introduction. (Pull ________ weeds)
  • Increased use of biodegradable packaging materials which will _________ quickly to the environment. (When considering a new purchase first: reduce, reuse, recycle)
  • Use fuels which contain less pollutants such as low sulfur coal. (Or insert _______ panels on your home!)
  • Remove pollutants before they enter the air by using such devices as catalytic converters. (Don't smoke or burn ________)