1. Chapter 5 Biodiversity, Species Interactions, and Population Control

2. Species Interact in Five Major Ways
Interspecific Competition
Predation
Parasitism
Mutualism
Commensalism

3. Parisitism (host)

4. tick
tapeworm
Cordyceps (fungus) … “bite & die”

5. Mutualism:
Clownfish with
Sea Anemone
Livestock with tickbird

6. Mutualism (cont’d)
Egyptian Plover
Cleaning crocodile’s teeth

7. Mutualism (cont’d)
Remora fish and shark

8. Commensalism: + doesn’t care

9. Science Focus: Threats to Kelp Forests
Kelp forests: biologically diverse marine habitat
Major threats to kelp forests
Sea urchins
Pollution from water run-off
Global warming

10. Purple Sea Urchin
Figure 5.A: This purple sea urchin inhabits the coastal waters of the U.S. state of California.
Fig. 5-A, p. 108

11. Populations Can Grow, Shrink, or Remain Stable (1)
Population size governed by
Births
Deaths
Immigration
Emigration
Population change =
(births + immigration) – (deaths + emigration)

12. No Population Can Grow Indefinitely: J-Curves and S-Curves (1)
Size of populations controlled by limiting factors:
Light
Water
Space
Nutrients
Exposure to too many competitors, predators or infectious diseases

13. No Population Can Grow Indefinitely: J-Curves and S-Curves (2)
Environmental resistance
All factors that act to limit the growth of a population
Carrying capacity (K)
Maximum population a given habitat can sustain

14. Some Ecosystems Start from Scratch: Primary Succession
No soil in a terrestrial system
No bottom sediment in an aquatic system
Takes hundreds to thousands of years
Need to build up soils/sediments to provide necessary nutrients

15. Primary Ecological Succession
Figure 5.19: Primary ecological succession: Over almost a thousand years, these plant communities developed, starting on bare rock exposed by a retreating glacier on Isle Royal, Michigan (USA) in northern Lake Superior. The details of this process vary from one site to another. Question: What are two ways in which lichens, mosses, and plants might get started growing on bare rock?
Fig. 5-19, p. 119

16. Some Ecosystems Do Not Have to Start from Scratch: Secondary Succession (1)
Some soil remains in a terrestrial system
Some bottom sediment remains in an aquatic system
Ecosystem has been
Disturbed
Removed
Destroyed

17. Natural Ecological Restoration of Disturbed Land
Figure 5.20: Natural ecological restoration of disturbed land: This diagram shows the undisturbed secondary ecological succession of plant communities on an abandoned farm field in the U.S. state of North Carolina. It took 150–200 years after the farmland was abandoned for the area to become covered with a mature oak and hickory forest. A new disturbance such as deforestation or fire would create conditions favoring pioneer species such as annual weeds. In the absence of new disturbances, secondary succession would recur over time, but not necessarily in the same sequence shown here. See an animation based on this figure at CengageNOW. Questions: Do you think the annual weeds (left) would continue to thrive in the mature forest (right)? Why or why not?
Fig. 5-20, p. 120

18. Some Ecosystems Do Not Have to Start from Scratch: Secondary Succession (2)
Primary and secondary succession
Tend to increase biodiversity
Increase species richness and interactions among species
Primary and secondary succession can be interrupted by
Fires
Hurricanes
Clear-cutting of forests
Plowing of grasslands
Invasion by nonnative species