Download - Day 22 december 2 chapter 15
Day 22 December 2 Chapter 15
Dr. Amy B HollingsworthThe University of Akron
Fall 2014
15.9 Interacting species evolve together.
Natural Selection Causes organisms to become better adapted
to their environment
Does not distinguish between biotic and abiotic resources as selective forces
15.10. Each species’ role in a community is defined by its niche.
More than just a place for living, a niche is a complete way of living.
“You can’t always get what you want.”
Fundamental niche• the full range of environmental conditions under
which a species can live
Realized niche• where and how a species is actually living
15.11 Competition can be hard to see, but it still influences community structure.
Why is competition hard to see in nature?
The “ghost of competition past”
15.12 Predation produces adaptation in both predators and their prey.
Predation
One of the most important forces shaping the composition and abundance of species in a community
Why do exotic species often flourish when released into novel habitats, even though natural selection has not adapted them to this new environment?
Prey Adaptations for Reducing Predation
There are two broad categories of defenses against predators:
• Physical
• Behavioral
Physical Defenses
Include mechanical, chemical, warning coloration, and camouflage
mechanisms
1. Mechanical Defenses
2. Chemical Defenses
3. Warning Coloration
4. Camouflage
Behavioral defenses
Include both seemingly passive and active behaviors: hiding or escaping,
or alarm calling or fighting back
Predator adaptations for enhancing predation
Why don’t predators become so efficient at capturing prey that they drive the prey to extinction?
The “life-dinner hypothesis”
Parasite Predators
Parasites have some unique features and face some unusual challenges:• The parasite generally is much smaller than its host
and stays in contact with the host for extended periods of time.
• Complicated life cycles as means of getting from host to host.
Case 1: Parasites can induce foolish, fearless behavior in their hosts.
Toxoplasma
Rats and cats
Case 2: Parasites can induce inappropriate aggression in their hosts.
Case 3: Parasites can induce bizarre and risky behavior in their hosts.
The lancet fluke
15.14. Not all species interactions are negative: mutualism and commensalism.
15.15–15.16 Communities can change or remain stable over time.
15.15. Many communities change over time.
Secondary Succession
Much faster than primary succession• life and soil are already present
15.16. Some species are more important than others within a community.
Chapter 16: Conservation and Biodiversity
Human influences on the environmentLectures by Mark Manteuffel, St. Louis Community College
16.1–16.4 Measuring and defining biodiversity is complex.
16.1 Biodiversity benefits humans in many ways.
Consider also the following:
Vinblastine and vincristine
Ancrod
Epibatidine
16.2 Biodiversity is not easily defined.
16.3 Where is most biodiversity?
Why are there more species in an acre of tropical rain forest than in an acre farther from the equator, such as in a temperate forest or prairie?
Latitudinal Biodiversity Gradient