1. Warm-Up (2/29)
Name
Date
Period
Dr. Fleenor cut down banana trees this past weekend which appeared to be dead. Healthy leaves appear green, erect and broad; but these leaves appeared brown, drooping, and shriveled. He was surprised to find that inside the stem of the banana trees were many vascular structures filled with water. When he cut down a healthy banana tree last summer (for no reason than to assert his macho-masculinity), he found the same vascular structures, but they were not filled with water. This observation was most likely due to –
an increased rate of photosynthesis in the trees, resulting in the production of water
an increased rate of absorption of water from the roots to meet the demands of the struggling plant
a decreased rate of transpiration in the leaves, preventing the turgor pressure which draws water out of the stem
a decreased rate of root synthesis, resulting in fewer structures to absorb water
Explain why your answer choice is correct (LO 2.23).

2. 2D.1b: Organism activities are affected by interactions with abiotic and biotic factors.
Illustrative example: symbiosis
4A.5b: Mathematical or computer models are used to illustrate and investigate population interactions within environmental impacts on a community.
Illustrative example: graphical representation of field data
4A.5c: Mathematical models and graphical representations are used to illustrate population growth patterns and interactions.
4A.5c.1: Reproduction without constraints results in the exponential growth of a population.
4A.5c.2: A population can produce a density of individuals that exceeds the system’s resource availability.
4A.5c.3: As limits to growth due to density-dependent and density-independent factors are imposed, a logistic growth model generally ensues.
4A.5d.4: Demographics data with respect to age distributions and fecundity can be used to study human populations.
4B.3a: Interactions between populations affect the distributions and abundance of populations.
4B.3a.1: Competition, parasitism, predation, mutualism and commensalism can affect population dynamics.
4B.3a.2: Relationships among interacting populations can be characterized by positive and negative effects, and can be modeled mathematically (predator/prey, epidemiological models, invasive species).

3. Population Interactions, Part I
Regulated population size follows a logistic curve.

4. Population Interactions, Part I
Unregulated population size increases exponentially.
carrying capacity
Population density
Time

5. Population Interactions, Part I
Unregulated population size increases exponentially.
Eventually, all populations are limited and regulated by resources.
carrying capacity
Population density
Time

6. Not benefitted or harmed
Population Interactions, Part I
Interactions can be positive or negative:
Relationship
Organism #1
Organism #2
Mutualism
Benefitted
Commensalism
Not benefitted or harmed
Parasitism
Harmed
Predation
Killed
Competition

7. Population Interactions, Part I
Interactions can be positive or negative:

8. Critical Thinking Questions #1 & #2
The population size of a native species of bullfrog, H. habilitis, was measured in a forest community over several years. Seven years after the start of the study, a non-native tree fungus, P. buscelli, was introduced to the community. The population of the native bullfrog, as well as the tree fungus, was measured for an additional four years.
CTQ #1: Calculate how many times greater the bullfrog population size was after 11 years than when the tree fungus was introduced at year 7. (LO 4.12)

9. Critical Thinking Questions #1 & #2
The population size of a native species of bullfrog, H. habilitis, was measured in a forest community over several years. Seven years after the start of the study, a non-native tree fungus, P. buscelli, was introduced to the community. The population of the native bullfrog, as well as the tree fungus, was measured for an additional four years.
CTQ #2: H. habilitis normally feeds on a population of beetles which grow at the base of trees. After six years of study, it was concluded that the population of H. habilitis had reached it carrying capacity, or maximum size based on available resources. Explain how the non-native tree fungus P. buscelli, introduced after seven years of study, increased the carrying capacity of H. habilitis (LO 4.19).

10. Closure
On the piece of white paper from the back, answer the following question:
Name
Date
Period
Predict how the size of the native bullfrog will change in the ten years following the study.
Scale 1 – 10