Chapter 4 Biological Communities and Species Interactions

1
Chapter 4Biological Communities and Species
Interactions

• Who Lives Where and WHY???
• AP Environmental Science

2
Objective 1

• Describe how environmental factors determine
  which species live in a given ecosystem and where
  or how they live.

3
Tolerance Limits

• What are the tolerance limits of a human?
• Temperature
• Shelter
• Food
• Water
• Social structure
• What is a critical factor for humans?

4
Tolerance Limits and Critical Factors

• Tolerance Limit
• The high and low spectrum for each environmental
  factor in an organisms life.
• Critical Factor
• The single factor closest to an organisms
  survival limits.
• http//curriculum.calstatela.edu/courses/builders/
  lessons/less/les5/limit.html

5
Liebig's Law of the Minimum

• Often simply called Liebig's Law or the Law of
  the Minimum, is a principle developed in
  agricultural science by Justus von Liebig. It
  states that growth is controlled not by the total
  of resources available, but by the scarcest
  resource.

6
Liebig's Law of the Minimum

• Liebig used the image of a barrelnow called
  Liebig's barrelto explain his law. Just as the
  capacity of a barrel with staves of unequal
  length is limited by the shortest stave, so a
  plant's growth is limited by the nutrient in
  shortest supply.

7
Liebig's Law of the Minimum

• Liebig's Law has been extended to biological
  populations. For example, the growth of a
  biological population may not be limited by the
  total amount of resources available throughout
  the year, but by the minimum amount of resources
  available to that population at the time of year
  of greatest scarcity. That is, the growth of a
  population of animals might depend not on how
  much food is available in summer, but on how much
  food is available in winter.

8
Do these laws really work?

• NO.
• I tossed the seal experiment at you to get you
  thinking. Its more complex than one thing.
  Think about your life your successes and
  failures.
• WHALE STORY
• Polar Bears TOO!

9
Polar BEAR Issues

• A team of researchers from Canada, Alaska,
  Denmark and Norway found large quantities of PCBs
  (Polychlorinated biphenyl), pesticides and a
  brominated flame retardant, which aside from the
  negative impact on thyroid glands, motor skills
  and brain function, has also led to the increase
  in number of hermaphrodite bears.According to
  the findings, one in 50 female bears in the
  Svalbard Island had both sets of sexual organs,
  and researchers say this statistic is directly
  linked to pollution.

10
Of Wolves, Coyotes and Fox

• Presettlement spatial relationships among home
  ranges of three packs of wolves, two families of
  coyotes, and two families of foxes near a Native
  American village with free-ranging dogs. Buffer
  zones and boundaries of wolf pack territories are
  dynamic, changing with availability of food and
  composition of wolf packs.

11
Of Wolves, Coyotes and Fox
12
HmmmWhat do you think happened?

• Heres your essay question for Chapter 4 Gang.
• You will get it tomorrow.

http//biology.usgs.gov/st/noframe/q209.htm23084
13
EPA Indicators

• http//www.epa.gov/bioindicators/html/key.html
• How does the EPA use indicators to assess the
  health of an ecosystem?

14
Objective 2

• Understand how random genetic variation and
  natural selection lead to evolution, adaptation,
  niche specialization, and partitioning of
  resources in biological communities.

15
Biology Review GANG

• Genetic variation
• Natural selection
• Evolution
• Adaptation
• Niche specialization
• Partitioning of resources

16
Natural Selection
17
Natural Selection
18
Genetic variation
19
Sometimes You feel like a NUT
20
What is the Advantage of Genetic Variation?
21
Git ER Done!
22
Evolution
23
Evolution

• SO What is the theory, REALLY?

24
Evolution
25
Homologous Structures
26
Adaptation

• How is this an
• example
• of Adaptation?
• Is it a good
• Example?
• Why? Why not?

27
How is this animal adapted?
28
Niche specialization
29
Niche Specialization
30
Partitioning of resources
31
Problems with Resource allocation

• Competition interspecies and intraspecies
• Overlap
• Specialization
• Limited resources available

32
Competition between species
33
Limited resources available
34
Competition can be fierce for limited
resources/niche overlap!
35
Picky Eaters

• Equates to
• Certain death
• When theres
• change

36
Questions?