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STUDY GUIDE: ECOLOGY
ECOLOGY: Study of relationships between living things & their environment.
Ecosystem: All the living (biotic) & nonliving (abiotic) things that surrounds a living thing.
Biotic Examples: living (lion, tigers, bears, trees, venus flytrap, flowers, bacteria, yeast, amoebas)
Abiotic Examples: non-living (Rocks, soil, water currents, air (climate), sand, dirt, ice (glaciers), fossils, buildings, roads)
LEVELS OF ORGANIZATION IN THE ENVIRONMENT:
Organism: One living thing. (Ex.--1 zebra.)
Population: A group of similar life forms in an area. (Ex- Herd of zebras.)
Community: Groups of populations that interact with each other. (Ex.zebras, trees, lions, rabbits, grass)
Ecosystem: Communities & their abiotic surroundings. (Desert: owls, rain, cacti, scorpions, sunlight)
Biosphere: All the earth's ecosystems. All life, as well as, the earth itself and the atmosphere.
RELATIONSHIPS:
Producer: Green plants and phytoplankton. (Use the sun's energy to make food for themselves & others)
Consumers: All creatures that muste eat other creatures to get the energy they need to live.
Types of consumers include:
Herbivores: Eat producers ; mostly plant materials. Ex.--Cows, horses, gerbils, ducks, brontosaurus, etc
Carnivores: Eat other consumers ; mostly meat of animals. Ex.--Lions, tigers, beagles, hawks, centipede, etc
Omnivores: Eat plants & animals. Ex.--Bears, humans, chimps, raccoon, opossum, etc...
Detritovores: Eat dead animals & plants. Ex.--Flies, maggots, vulture, hyaena, bald eagle.
Decomposers: Microscopic organisms that break down the living matter of dead creatures into nonliving soil,
which helps recycle nutrients. Ex. Bacteria, fungi (mushrooms, yeast, & molds).
INTERACTIONS:
Predation: One organism kills and eats another to obtain the energy & nutrients it needs.
Predator: The one that kills and eats the other.
Prey: The one that is eaten.
(lynx, bears, hawks, spiders, Venus flytrap, pitcher plant)
(rabbits, worms, snakes, mice, insects)
Competition: species attempt to use the same limited resource (same food, water, shelter, etc.).
A. Lion, hyena, & vulture competing for same carcass.
B. Different bird species competing for same nesting space.
Symbiosis: Relationship between 2 different kinds of organisms that live together in some way.
1. Mutualism: both creatures benefit.
Ex- A. Ants and aphids (ants get honey dew from aphids, aphids get protection.)
B. Rhino & Tick Bird (Rhino gets rid of ticks & fleas , Tick Bird gets free food.)
2. Commensalism: one creature is helped, the other is neither helped nor hurt.
Ex- A. Shark & Remora fish (Shark not helped nor hurt, Remora gets free food, rides, and protection.)
B. Barnacles & Whale (Barnacle gets free ride & food, whale not affected.)
C. Orchid atop Palm Tree: (Orchid gets to live nearer to sunlight, tree not affected.)
3. Parasitism: one creature is helped, the other is harmed.
Host is the creature the parasite lives on. Parasite is the creature harming the other.
Ex- Parasites: Leech, Tick, Flea, Tapeworm, Liver Fluke, Malaria, Lamprey Eel, Mistletoe
SUCCESSION is a series of changes that take place in a communitiy as it gets older
Climax Community: The last or final stage of succession in a community. “Old growth” high biodiversity
Ex. 1000 year old desert or 5000 year old pine forest
Primary Succession: Succession that occurs on an area that never had life on it before. Starts with bare rock
Ex. volcanic action or melting of glaciers
Pioneer Plants: the 1st plants that live in an area after a disturbance.
During primary succession: Lichens are common pioneer plants on rock.
During secondary succession: mosses, grasses, and weeds
Lichen: 2 creatures that live together and help each other (mutualism). A fungus provides a home and absorbs minerals
and water from the rock. An algae lives inside the fungus and makes food via photosynthesis.
Secondary Succession: the community is changed after a disturbance. Soil already exists
Ex. fires, floods, earthquakes, landslides, farming, logging, road building, and home or building construction.
POPULATION CHANGE
Population density: the number of organisms living per unit area. Patterns can be clumped, uniform or random.
Pop. = # of organisms divided by the area
(Ex. 18 penguins / 6 square feet = 3 penguins/ft2)
Logistic Growth Model: S-shaped. Fast growth in middle part,
constant when reaches carrying capacity.
Carrying Capacity: maximum number of individuals the habitat
can support ( before equilibrium)
Exponential Growth Model: grows very fast infinitely (population crash
when the resources are exhausted. It is J- shaped.
Human population Growth – Overall = exponential.
In most of developed world population is either slowly growing (USA) or decreasing (Italy) but increasing very fast in
most of the less developed world (Afganistan).
The age structure figures help us understand population growth.
Fast growing population the base is broad and narrows to a point (pyramid)
(less developed country - Afganistan).
Stable population has base and middle part equal; and
(Developed country = USA)
Declining population has narrow base than middle.
(Limited Resources = Italy)