1. What Shapes an Ecosystem?

2. What Shapes an Ecosystem?
Biotic Factors – living/biological influences on organisms within an ecosystem.
Examples?
Abiotic Factors – physical/non-living influences on organisms within an ecosystem.
*Together, biotic and abiotic factors determine the survival and growth of an organism and the productivity of the ecosystem in which the organism lives = habitat (= home of organism; its “address”)

3. Abiotic and Biotic Factors
Abiotic Factors
Biotic Factors
ECOSYSTEM

4. Abiotic and Biotic Factors
Abiotic Factors
Biotic Factors
ECOSYSTEM

5. Abiotic Factors of the Biosphere: Energy Source
Not all areas on Earth receive the same amount of light energy
In aquatic enviroments, light cannot reach far down, so photosynthesis tends to occur near the surface of the water

6. Abiotic Factors of the Biosphere: Temperature
Temperature affects metabolism.
Few organisms can maintain a sufficiently active metabolism at temperatures close to 0ºC.
Temperatures above 45ºC destroy the enzymes of most organisms.
Most organisms function best within a specific range of environmental temperatures.

7. Abiotic Factors of the Biosphere: Water
Water is essential to all life.
For terrestrial organisms, the main water problem is drying out.
Aquatic organisms
are surrounded by water and
face problems of water balance if their own solute concentration does not match that of their surroundings.

8. Abiotic Factors of the Biosphere: Inorganic Nutrients
The distribution and abundance of plants are often determined by the
availability of inorganic nutrients such as nitrogen and phosphorus and
the structure, pH, and nutrient content of the soil.
In many aquatic ecosystems, the growth of algae and photosynthetic bacteria is often limited by levels of
nitrogen and
phosphorus.

9. Abiotic Factors of the Biosphere: Other Factors
Aquatic but not terrestrial ecosystems are more limited by
the levels of dissolved oxygen,
salinity,
currents, and
tides.
Terrestrial but not aquatic ecosystems are more limited by
wind,
storms, or
fire.

10. Biotic vs. Abiotic

11. Biotic vs. Abiotic

12. Biotic vs. Abiotic

13. Biotic vs. Abiotic

14. Adjusting to Environmental Variability
The abiotic factors in a habitat may vary
from year to year,
seasonally, or
over the course of a day.
For example: Birds may adjust to cold by
migrating to warmer regions (a behavioral response),
growing heavier feathers (an anatomical response), or
fluffing up their feathers to trap more heat (a physiological response).

15. Adjusting to Environmental Variability: Physiological
Acclimation is
gradual, reversible, and
a physiological adjustment to an environmental change.
The ability to acclimate is generally related to the range of environmental conditions a species naturally experiences.
Among vertebrates,
birds and mammals can tolerate the greatest temperature extremes because they are endotherms, while
ectothermic reptiles can only tolerate a more limited range of temperatures.

16. Adjusting to Environmental Variability: Anatomical
Many organisms respond to environmental challenges with some type of change in
body shape and
structure.
Anatomical responses are not reversible – growth and development is limited – trees grow smaller in very windy enviroments

17. Adjusting to Environmental Variability: Behavioral
In contrast to plants, most animals can respond to an unfavorable change in the environment by moving to a new location.
Ectotherms may shuttle between sun and shade.
Migratory birds travel great distances in response to changing seasons.
Humans have an especially rich range of behavioral responses.

18. The Niche Niche = the ROLE of an organism in its habitat
What is the organism’s job?
What does the organism do for its environment?
The niche is the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions – use of biotic and abiotic resources
place in food web, range of temperatures needed to survive, food, physical conditions necessary for survival, reproduction, etc.

19. Warblers and Their Niches
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
Spruce tree

20. Competitive Exclusion Principle
Competitive Exclusion Principle - no two species can share the exact niche in the same habitat at the same time…Why? One will become extinct.

21. Separate cultures Combined cultures 2 4 6 8 10 12 14 16 P. aurelia
Relative population density
Combined
cultures 2 4 6 8 10 12 14 16
P. aurelia
P. caudatum

22. Community Interactions - Interspecific
Interspecific interactions are interactions between species.
Powerfully affect an ecosystem
Four important types of interactions
Competition
Predation
Herbivory
Symbiosis

23. Competition
Competition – organisms compete for resources (food, water, shelter, etc)

24. Predation
Predation – one organism (predator) captures and feeds on another (prey)

25. Predation
Numerous adaptations for predator avoidance have evolved in prey populations through natural selection.
Cryptic coloration is
camouflage and
a way for prey to hide from predators.
A warning coloration is
a brightly colored pattern and
a way to warn predators that an animal has an effective chemical defense.

26. Predation Non-venomous scarlett king snake
Venomous eastern coral snake

27. Herbivory
Herbivory is the consumption of plant parts or algae by an animal.
Plants have evolved numerous defenses against herbivory, including
spines,
thorns, and
chemical toxins.

28. Symbiosis Symbiosis – two species live closely together
Three major types of symbiosis
Mutualism
Commensalism
Parasitism

29. Symbiosis - Mutualism Host Symbiont
Example: flower & bee – both organisms benefit from each other
Other examples?

30. Mutualism Examples

31. Symbiosis - Commensalism
Host Symbiont
Example: barnacle and whale – one organism benefits, the other is not hurt nor harmed
Other examples?

32. Commensalism Examples

33. Symbiosis - Parasitism
Host Symbiont
Example: tapeworm and human – one organism benefits while the other is harmed
Other examples?

34. Parasitism Examples

35. Ecological Succession
Ecological Succession – series of predictable changes that occurs in a community over time
*Ecosystems are constantly changing in response to natural and human disturbances. As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community.

36. Primary Succession
Bare rock to plant community – like on a volcanic island
First species to populate are called pioneer species (usually lichens)
No soil – have to make it by breaking down rocks first

37. Primary Succession

38. Secondary Succession
Soil to climax community (stable, mature community)
Wildfires, farms, marine environments
Soil already there