Unit 2 -- Principles of Ecology

1
Unit 2 -- Principles of Ecology

• Ecology Scientific study of how organisms and
  their surrounding environments interact

2
Abiotic vs. biotic factors presence/absence of
these define levels of organization

• Abiotic nonliving parts of an orgs surrounding
  environment
• Ex. Soil, moisture, light, temperature
• (though nonliving, abiotic factors are an
  important part of an organisms life)
• Biotic all of the living organisms that live in
  a particular area under consideration.
• Ex. Goldfish in a bowl, other goldfish,
  plants, algae

3
Levels of Organization

• Individual organism Ex. One frog
• Species Ex. Bullfrogs
• group of organisms so similar to one another
  that they can breed and produce FERTILE
  offspring.
• Population Ex. Bullfrogs in a pond
• group of organisms of ONE species that
  interbreed and live in the same area at the
  same time.
• Community Ex. Bullfrogs, fish, insects, algae in
  that pond
• made up of several populations that interact in
  the same area
• Ecosystem Ex. Pond ecosystem
• collection of ALL the living things that live in
  a particular place together with their physical
  environment
• Biome Ex. Tropical rainforest
• group of ecosystems with the same climate and
  similar dominant communities
• Biosphere Ex. Earth and atmosphere above it
• Consists of the portion of Earth that supports
  life. (includes land, water, atmosphere)

4
Organisms in Ecosystems

• Habitat place where an org lives its
  day- to-day life.
• (habitats can change dramatically due to
  natural or man-made effects
• Ex. fire because of lightning or careless
  campers...
• Niche the role and position a species occupies
  in its habitat or location. HOW it lives in the
  habitatThis includes all of the orgs
  interactions with the living and nonliving parts
  of the habitat.
• Ex. Earthworms act as decomposers

5
Chapter 14 --

• Interactions in Ecosystems section 14.1,
• pages 426-434

6
Resource Availability and competitive exclusion

• 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

7
Other outcomes of competitive exclusion.

• Niche partitioning
• Natural division of resources based on
  competitive advantages
• Ex. One squirrel eats nuts from top of tree, one
  squirrel eats nuts from the ground
• Evolutionary response
• Divergent evolution (body forms change over time)
• Ex. Large teeth for large nuts, small teeth for
  small nuts

8
What happens in different communities

• Ecological equivalents
• Species that occupy similar niches but live in
  different geographical regions
• Ex. Poison dart frog of SA
• and
• Mantella frog of Madagascar

9
Community Interactions

• Competition
• Predation
• Symbiosis
• for tomorrows lab, we will deal with the
  symbiosis considerations.

10
Living Together species interactions

• Symbiosis relationship where there are close
  and long-lasting associations between orgs of
  different species
• Types of symbiotic relationships
• a. parasitism
• b. commensalism
• c. mutualism

11
Parasitism

• 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)

12
Each section of a tapeworms body is called a
PROGLOTTID and contains a full set of
reproductive organs
13
Commensalism

• 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

14
(No Transcript)
15
Mutualism

• 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

16
(No Transcript)
17
(No Transcript)