Unit 2 -- Principles of Ecology. Ecology: Scientific study of how organisms and their surrounding environments interact. Abiotic vs. biotic factors – presence/absence of these define levels of organization. Abiotic – nonliving parts of an orgs surrounding environment
Ecology: Scientific study of how organisms and their surrounding environments interact
Ex. Soil, moisture, light, temperature
(though nonliving, abiotic factors are an important part of an organism’s life…)
Ex. Goldfish in a bowl, other goldfish, plants, algae
group of organisms so similar to one another that they can breed and produce FERTILE offspring.
group of organisms of ONE species that interbreed and live in the same area at the same time.
made up of several populations that interact in the same area
collection of ALL the living things that live in a particular place together with their physical environment
group of ecosystems with the same climate and similar dominant communities
Consists of the portion of Earth that supports life. (includes land, water, atmosphere)
(habitats can change dramatically due to natural or man-made effects:
Ex. fire because of lightning or careless campers...
Ex. Earthworms act as decomposers
Interactions in Ecosystemssection 14.1,
Gives structure to a community
Many species can share similar habitats and use some of the same resources…
BUT, when two species use the same resources in the same ways, Competitive exclusion comes in to play:
DEF: when 2 species are competing for the same resources, one species will be better suited to the niche and the other species will be pushed into another niche or become extinct
Ex. NA Gray squirrel vs. Red squirrel in Great Britain
Gray is larger, more aggressive
Natural division of resources based on competitive advantages
Ex. One squirrel eats nuts from top of tree, one squirrel eats nuts from the ground
Divergent evolution (body forms change over time)
Ex. Large teeth for large nuts, small teeth for small nuts
Species that occupy similar niches but live in different geographical regions
Ex. Poison dart frog of SA
Mantella frog of Madagascar
*for tomorrow’s lab, we will deal with the symbiosis considerations….
Symbiosis– relationship where there are close and long-lasting associations between orgs of different species
Types of symbiotic relationships:
Symbiotic relationship where one organism benefits and another organism is harmed.
Ex. Ticks on a dog
-- tick gets food source, dog gets hole in protective skin layer and possible infection
Ex. Tapeworms in intestine
-- tapeworm absorbs nutrients in pre-digested form, host loses weight, and host never gets the nutrition that it needs (malnutrition)
Each section of a tapeworm’s body is called a PROGLOTTID and contains a full set of reproductive organs…
Symbiotic relationship where one species benefits and another is neither harmed nor helped
Ex. Barnacles attached to a whale
-barnacles get a free ride to areas where food is available
Symbiotic relationship where both species involved benefit from the association.
Ex. Ants and acacia trees
– ants get shelter and nectar from plant as food, plants get protection from predators
Ex. sponges attached to crab shell
-- sponges get moved to new area to filter food from water, crab gets portable camouflage