1. Unit 9 - Ecology

2. B-6.1 Explain how the interrelationships among organisms (including predation, competition, parasitism, mutualism, and commensalism) generate stability within ecosystems.
Summarize how a stable ecosystem is obtained
Identify/illustrate roles of various organisms in an ecosystem (predator, prey, parasite, host) using pictures, diagrams, or words
Interpret a graph of predator/prey numbers over time
Explain how the numbers of various organisms fluctuate in an ecosystem to maintain stability
Exemplify biological relationships
Explain how a significant change in the numbers of a particular organism will affect the stability of the ecosystem
Classify a symbiotic relationship as mutualism, parasitism or commensalism
Summarize each of the types of biological relationships
Compare how various types of biological relationships affect the organisms involved

3. Ecology
Scientific Study of interactions among organisms and how they interact with their environment

4. Levels of Organization

5. Levels of Organization
Species – group of organisms similar to one another
Can breed & produce fertile offspring
Organism: one individual member of this species
Populations – groups of individuals belonging to the same species, live in the same area

6. Levels of Organization
Community – different populations living together in a defined area
Includes many species (all biotic)
Ecosystem – collection of all organisms living in a particular place together
Community and the factors that affect them
Biotic and abiotic factors

7. Levels of Organization
Biome – group of ecosystems
having the same climate & similar dominant communities
Biosphere - the portion of the earth
that supports life
- composed of living and non-living things

8. Biotic factors All living components of an ecosystem Examples:
Bacteria
Fungi
Plants
Animals

9. Abiotic factors Chemical or physical Examples: Water Nitrogen Oxygen
(non-living factors)
Chemical or physical
Examples:
Water
Nitrogen
Oxygen
Salinity (salt) pH
Soil nutrients & composition
Temperature
Amount of sunlight
Precipitation

10. In a stable ecosystem:
Population #’s of each organism fluctuate at a predictable rate
2. Supply of resources in physical environment fluctuates at a predictable rate
3. Energy flows through ecosystem at a fairly constant rate over time
Constant interaction within an ecosystem generates stability

11. Community Interactions
Predation
Predator
Prey
Competition
Niche
Symbiotic relationships
Parasitism
Mutualism
Commensalism

12. Predation Interaction between species
One species (predator) eats the other (prey)
Helps regulate population within ecosystem
Causes stability

13. Predation Fluctuations in predator-prey populations are predictable
At some point, prey population grows so numerous that they are easy to find

14. As prey population increases, predator population increases
As predator population increases, prey population decreases

15. Competition Relationship that occurs when 2
or more organisms need the same resources at the same time
Can be same or different species
Usually with organisms sharing the
same niche

16. Competition - niche Niche: role of an organism in its environment
Includes:
Type of food it eats
How it obtains its food
How it interacts with other organisms
2 species with identical ecological niches cannot coexist in the same habitat

17. Competition - results
decrease in the population of a species less adapted to compete for resource

18. Symbiotic Relationships
Exists between organisms of 2 different species that live together in direct contact
If a population of symbiotic organisms becomes unbalanced, all organisms fluctuate
3 types:
Parasitism
Mutualism
Commensalism

19. Parasitism
One organism (parasite) benefits at the expense of the other (host)
Parasite does not kill the host

20. Parasitism Some parasites live within the host Examples: Tape worms
Heartworms
Bacteria

21. Parasitism Some parasites feed on the external surface of a host
Examples:
Aphids
Fleas
Mistletoe

22. Parasitism Survival of parasite-host populations:
Neither has a devastating effect on the other
Death of parasite-host populations:
Devastating to both parasite & host
It’s important that the host survive & thrive long enough for the parasite to reproduce & spread

23. Mutualism Both organisms benefit
2 organisms work closely together to help each other survive
Example:
Bacteria: can digest wood, live within digestive tracts of termites
Plant roots: provide food for fungi that break down nutrients the plant needs
Clownfish and sea anemone
Insect and flower

25. Commensalism
One organism benefits & the other organism is not affected (not helped or harmed)
Examples:
Barnacles: attach to whales, dispersed to different environments where they obtain food & reproduce
Burdock seeds: attach to organisms & carried to locations where they can germinate
Bird nesting in tree