1. ECOSYSTEMS AND COMMUNITIES
Ecology
ECOSYSTEMS AND COMMUNITIES

2. Standard
The following standards will be addressed:
B-6.1
B-6.2

3. Objectives
Differentiate between a habitat and niche.
Differentiate between competitive exclusion and ecological equivalents.

4. KEY CONCEPT Every organism has a habitat and a niche.

5. A habitat differs from a niche.
A habitat is all aspects of the area in which an organism lives.
biotic factors
abiotic factors
An ecological niche includes all of the factors that a species needs to survive, stay healthy, and reproduce.
food
abiotic conditions
behavior

6. Resource availability gives structure to a community.
Species can share habitats and resources.
Competition occurs when two species use resources in the same way.
Competitive exclusion keeps two species from occupying the same niche.
One species will “win” while the other “looses”

7. Competitive exclusion has different outcomes.
One species is better suited to the niche and the other will either be pushed out or become extinct.
The niche will be divided.
The two species will further diverge.
This can lead to a new species, called speciation.

8. Ecological equivalents are species that occupy similar niches but live in different geographical regions.
Madagascar
South America

9. Objectives
Compare and Contrast interspecific and intraspecific competition.
Describe three types of symbiosis.
14. 2 notes

10. Standard
The following standards will be addressed:
B-6.1

11. KEY CONCEPT Organisms interact as individuals and as populations.

12. Community Interactions
Some species enhance their chance of survival by forming relationships with other species.
Types:
1) Competition
2) Predation
3) Symbiotic Relationships

13. Competition and predation are two important ways in which organisms interact.
Competition occurs when two organisms fight for the same limited resource.
Intraspecific competition
Interspecific competition

14. Competition
Interspecific competition occurs when organisms of different species attempt to use an ecological resource in the same place at the same time.
Intraspecific competion
is when organisms of
the same species
attempt to use a
resource at the same
time.

15. Adaptations to Avoid Competition
Reduce niche size
Natural selection among organisms
Character displacement
Example: Finches on Galapagos Islands all eat the seeds from the small variety of plants on the islands, but the bird’s beak size determines the size of the seed that it can eat. This allows others to eat the seeds as well, just of different sizes.
Immigration and Emigration of organisms
Resource partitioning
Using only a part of a resource; sharing

16. Predation occurs when one organism captures and eats another.

17. Adaptations to Avoid Predation
Animal Adaptations
Some organisms flee when a predator arrives.
Some use mimicry or camouflage.
Some use deceptive markings such as fake eyes.
Some produce toxins.
Plant Adaptations
Plants cannot run away from predators.
Some have sharp thorns, spines, sticky hairs, and tough leaves.
Some have chemical defenses which are poisonous to predators.

18. Community Interactions
A symbiotic relationship is one in which two organisms live together (symbiosis)
There are 3 types of symbiotic relationships:
Mutualism
Commensalism
Parasitism

19. There are three major types of symbiotic relationships.
Mutualism: both organisms benefit

20. There are three major types of symbiotic relationships.
Commensalism: one organism benefits, the other is unharmed
Human Our eyelashes are home to tiny mites
that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle.
Demodicids Eyelash mites find all they need to survive in the tiny follicles
of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. +
Organism benefits Ø
Organism is not affected
Commensalism

21. There are three major types of symbiotic relationships.
Parasitism: one organism benefits, the other is harmed
Organism benefits _
Organism is not affected
Hornworm caterpillar
The host hornworm will eventually die as its organs are consumed
by wasp larvae.
Braconid wasp
Braconid larvae feed on their host and release themselves shortly before reaching
the pupae stage of development.
Parasitism +

22. There are three major types of symbiotic relationships.
Parasitism meet their needs as ectoparasites (such as leeches) and endoparasites (such as hookworms)