Download 1 Ecological Interactions Packet

AP Biology Unit I: Ecological Interactions
Essential knowledge 1.C.1: Speciation and extinction have occurred throughout the Earth’s history.
Species extinction rates are rapid at times of ecological stress. • Human impact on ecosystems
Essential knowledge 2.A.1: All living systems require constant input of free energy.
Organisms use free energy to maintain organization, grow and reproduce.
Reproduction and rearing of offspring requires free energy beyond that which is used for maintenance and growth.
Different organisms use various reproductive strategies in response to energy availability.
• Seasonal reproduction in birds • Life-history strategy (biennial plants, reproductive diapause)
Changes in free energy availability can result in changes in population size.
• Change in energy resource level such as sunlight or in the producer level can affect the number and size of other
trophic levels.
Essential knowledge 2.A.2: Organisms capture and store free energy for use in biological processes.
Autotrophs capture free energy from physical sources in the environment.
Photosynthetic organisms capture free energy present in sunlight.
Heterotrophs capture free energy present in carbon compounds produced by other organisms.
Essential knowledge 2.A.3: Organisms must exchange matter with the environment to grow, reproduce and maintain
organization.
Molecules and atoms from the environment are necessary to build new molecules.
Carbon moves from the environment to organisms where it is used to build carbohydrates, proteins, lipids or nucleic
acids. Carbon is used in storage compounds and cell formation in all organisms.
Essential knowledge 2.D.1: All biological systems from cells and organisms to populations, communities and
ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy.
Organism activities are affected by interactions with biotic and abiotic factors.
• Predator–prey relationships • Water and nutrient availability, temperature, salinity, pH
The stability of populations, communities and ecosystems is affected by interactions with biotic and abiotic factors.
• Water and nutrient availability
Essential knowledge 2.D.3: Biological systems are affected by disruptionsto their dynamic homeostasis.
Disruptions to ecosystems impact the dynamic homeostasis or balance of the ecosystem. • Human impact
Essential knowledge 4.A.5: Communities are composed of populations of organisms that interact in complex ways.
The structure of a community is measured and described in terms of species composition and species diversity.
Mathematical or computer models are used to illustrate and investigate population interactions within and
environmental impacts on a community.
• Predator/prey relationships spreadsheet model • Graphical representation of field data
Mathematical models and graphical representations are used to illustrate population growth patterns and interactions.
1. Reproduction without constraints results in the exponential growth of a population.
2. A population can produce a density of individuals that exceeds the system’s resource availability.
3. As limits to growth due to density-dependent and density independent factors are imposed, a logistic growth model
generally ensues.
4. Demographics data with respect to age distributions and fecundity can be used to study human populations.
Essential knowledge 4.A.6: Interactions among living systems and with their environment result in the movement of
matter and energy.
Energy flows, but matter is recycled.
Changes in regional and global climates and in atmospheric composition influence patterns of primary productivity.
Organisms within food webs and food chains interact.
Food webs and food chains are dependent on primary productivity.
Models allow the prediction of the impact of change in biotic and abiotic factors.
1. Competition for resources and other factors limits growth and can be described by the logistic model.
2. Competition for resources, territoriality, health, predation, accumulation of wastes and other factors contribute to
density dependent population regulation.
Human activities impact ecosystems on local, regional and global scales.
1. As human populations have increased in numbers, their impact on habitats for other species has been magnified.
2. In turn, this has often reduced the population size of the affected species and resulted in habitat destruction and, in
some cases, the extinction of species.
Many adaptations of organisms are related to obtaining and using energy and matter in a particular environment.
Essential knowledge 4.B.3: Interactions between and within populations influence patterns of species distribution and
abundance.
Interactions between populations affect the distributions and abundance of populations.
1. Competition, parasitism, predation, mutualism and commensalism can affect population dynamics.
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. Many complex symbiotic relationships exist in an ecosystem, and feedback control systems play a role in the
functioning of these ecosystems.
A population of organisms has properties that are different from those of the individuals that make up the population.
The cooperation and competition between individuals contributes to these different properties.
Species-specific and environmental catastrophes, geological events, the sudden influx/depletion of abiotic resources or
increased human activities affect species distribution and abundance.
• Loss of keystone species
Essential knowledge 4.B.4: Distribution of local and global ecosystems changes over time.
Human impact accelerates change at local and global levels. • Introduction of new diseases can devastate native species
Essential knowledge 4.C.4: The diversity of species within an ecosystem may influence the stability of the ecosystem.
Natural and artificial ecosystems with fewer component parts and with little diversity among the parts are often less
resilient to changes in the environment.
Keystone species, producers, and essential abiotic and biotic factors contribute to maintaining the diversity of an
ecosystem. The effects of keystone species on the ecosystem are disproportionate relative to their abundance in the
ecosystem, and when they are removed from the ecosystem, the ecosystem often collapses.
What students should be able to do to demonstrate high achievement:
Big Idea 1: The Process of evolution explains the diversity and unity of life
1. Analyze data related to questions of speciation/extinction throughout Earth’s history: identify patterns
of speciation and/or extinction, determine rates of speciation and/or extinction.
Big Idea 2: Biological systems utilize energy for growth, reproduction, and to maintain homeostasis
1. Analyze data to identify possible patterns and relationships between a biotic or abiotic factor and a
biological system, identify and explain any anomalies in the pattern or relationship, and predict
consequences of a change in a biotic or abiotic factor(s) to the system.
2. Predict 1–2 consequences to organisms, populations, and ecosystems if sufficient free energy is not
available (e.g., death, changes in population size, changes to number and size of trophic levels in
ecosystems).
3. Describe 2–3 examples of how a cooperative behavior benefits both the individual and the population
(e.g., mutualistic relationships, niche partitioning) that involves timing and coordination of
activities/events.
Big Idea 3: Living systems store, retrieve, transmit, and respond to information
1. Justify how changes in internal or external clues affect the behavior of individuals and their
interactions within a population and between related individuals.
2. Describe how behavior is modified in response to external and internal cues for both animals and
plants using appropriate examples from each.
Big Idea 4: Biological systems interact
1. Pose scientific questions and apply mathematical routines to analyze interactions among community
components.
2. Predict the effect of a change in one of the components on the interactions within the community and
matter and energy flow.
3. Analyze data to develop and refine qualitative and quantitative models for species and population,
abundance, densities, distribution, and interactions and predict the effect(s) of human activity on the
biological system.
4. Analyze evidence to develop models and predictions as to the effect that changes in the level of
variation within populations and species diversity will have on fitness and system stability.
5. Refine models showing organism interaction and matter and energy flow in a biological system and
predicting the effects of a change in one of the components.
6. Analyze data to identify patterns depicting species and population abundance distribution and
interactions such as predator-prey, competition, and human activity effects.
7. Justify the claim that variation within populations and increased species diversity account for increased
population fitness and system stability.
Binkley et al. article discussion
http://www.rmtrr.org/data/Binkleyetal_2006_Ecosystems.pdf
1) Which journal was the article published in?
2) What was the year of publication?
3) What was the guiding question the article was designed to answer?
4) Who is the article written for (who is the intended audience)?
5) What is the purpose of the abstract section of such journal articles?
6) Contrast the bottom-up versus the top-down control mode of deer population control:
7) Summarize the deer population dynamics between 1906 and 2001 (see Figure 1):
8) Describe two types of data that were collected from aspen trees in the descriptive study:
9) Describe the three different areas where aspen trees were surveyed:
10) Why were trees surveyed across these three different areas?
11) How strong was the correlation between aspen tree diameter and age (see scatterplot in Figure 3)?
12) According to data presented in figure 4, which years had a higher than expected number of aspen
trees? Which years had lower than expected recruitment? Hypothesize a reason for the relationship:
13) According to Figure 5, it took aspen that were seedlings in the 1920 to 1930 time-range a long time to
reach a height of 1.5 m. What could account for this finding?
14) Describe and explain the relationship you see in the historic photos shown in Figure 7:
15) How did the pattern of aspen recruitment from 1920 to 1930 compare across the three areas
sampled?
16) How did grazing by livestock change the fire regime in the 1880s and how did this affect aspen
recruitment (see text on P. 235).
17) What was cited as evidence that deer population was not kept artificially low due to competition for
food from livestock in the 1880s?
18) In the conclusion, what do the authors suggest about the role of top-down versus bottom-up control in
regulating deer population?
19) The authors conclude by stating that some uncertainty remains within the overall story, as can be
expected for case studies that involve population ecology, land management, people, and large land
area and time scales. However, what value/role do the authors suggest this case study has for
education purposes?
What is the effect of plant abundance
and/or quality on herbivore abundance?
Density-Dependent Population Regulation Factors:
 Competition for resources

Predation

Disease

Toxic

Territoriality

Intrinsic factors
Claim:
Evidence:
What is the effect of reproduction on survivorship of the parent(s)?
Explain this relationship:
Interpret the Data
1.
What proportion of the solar energy that
reaches the marsh is incorporated into gross
primary production? (A proportion is the same
as a percentage divided by 100. Both
measures are useful for comparing relative
efficiencies across different ecosystems).
2.
How much energy is lost by primary producers
as respiration in this ecosystem? How much is
lost as respiration by the insect population?
3.
If all of the detritus leaving the marsh is plant
material, what proportion of all net primary
production leaves the marsh as detritus each
year?
Additional Practice Question
1.
If an insect that eats plant seeds containing
200 J of energy, uses 60 J of that energy for
respiration, and excretes 100 J in its feces,
what is the insect’s net secondary production?
What is its production efficiency?
Rate of Primary Productivity (Photosynthesis) Patterns in Terrestrial Ecosystems
Category
Temperature
Light-availability
Water-availability
Nutrient-availability
(especially N & P)
Herbivory
(predation)
Effect
Reason
Rate of Primary Productivity Patterns (Photosynthesis) in Aquatic Ecosystems
Category
Temperature
Light-availability
Nutrient-availability
(especially N in oceans & P in
fresh-water)
Herbivory (predation)
Effect
Reason
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