Oh Deer! (Populations)
Introduction:
The most basic needs of any animal are food, water, shelter and space. Without these vital components, animals cannot survive. Many factors affect the ability of wildlife to successfully reproduce and to maintain their population over time. Disease, predator/prey relationships, weather conditions from season to season (e.g., early freezing, heavy snows, flooding, and drought), pollution and habitat destruction are among these factors. Habitat components are the most basic and so the most critical of limiting factors in most nature.
Background:
· Habitat – place that provides shelter and food
· Niche – an organism’s role in its environment (ie: its place in a food web)
· Population – total # of one type of organism in a specific area
· Carrying capacity – total # of individuals an environment can hold.
· Exponential growth – constant growth
· Logistic growth curve – shows growth slowing or stopping after exponential growth
· Limiting factors – factor that causes population growth to decrease L
I. Problem Statement
Do wildlife populations remain constant at all times? Is one habitat component more important than the others?
II. Hypothesis
EXAMPLE: Wildlife populations do not remain constant at all times. Food is more important than any other resource. OR: All components are equally important for animal survivial.
III. Materials
Food, water, and shelter cards
Large space
IV. Procedure
SEE TEACHER FOR INSTRUCTIONS
1. Students make two lines, ten yards apart.
2. Number the students one through four.
3. Send the “ones” to stand on one of the lines, and all of the remaining students (the “twos,” “threes,” and “fours”) to stand on the other line.
The “ones” will represent deer, while the “twos,” “threes,” and “fours” represent habitat. The deer need food, water, and shelter in order to survive a year in the woods.
The deer will each seek only one of those components of their habitat during each “year”.
4. The deer and the habitat to turn their backs on one another.
The “deer” will seek a component of the habitat, while the “habitat” will represent one of the 3 components.
5. The deer and the habitat decide simultaneously, which component of the habitat they will seek or represent. Students “display” with the appropriate sign.
6. Count to three at which time the two lines turn to face one another.
7. The habitat stays on their line, while the deer move toward the habitat seeking the component represented by their hand position.
8. A deer finding and “capturing” the component they seek represents a successful year in the woods, and they “reproduce” by bringing the student who represented the habitat back with them to the “deer line.” Only one deer may take back a component of the habitat. If a deer fails to find the habitat component they sought, they “die,” becoming a part of the habitat and remaining on the “habitat line.”
9. Repeat steps 4-8 until 10 “years” have passed. Each year record the number of deer.
10. Return to the classroom, write the data on the board, and copy the data to your lab journal.
V. Data Table
Year / # Deer Population (Last year’s population plus #births in current year - #deaths in current year) / # Births / Birth Rate(# births from the current year / #population from previous year)*100 / # Deaths / Death Rate (#died from the current year / #population from previous year)*100 / Growth Rate
(Birth Rate + Immigration Rate) – (Death Rate + Emigration Rate)
1 / 6 / 0 / 0% / 0 / 0% / 0%
2 / 12 / 6 / 100% / 0 / 0% / 100%
3 / 12 / 6 / 50% / 6 / 50% / 0%
4 / 18 / 9 / 75% / 3 / 25% / +50%
5 / 6 / 3 / 17% / 15 / 83% / -66%
6 / 12 / 6 / 100 / 0 / 0% / +100%
7 / 14 / 7 / 58% / 5 / 42% / +16%
8* / 10 / 5 / 36% / 9 / 64% / -28%
9** / 8 / 4 / 40% / 6 / 60% / -20%
10 / 10 / 5 / 63% / 3 / 37% / =26%
11 / 6 / 3 / 30% / 7 / 70% / -40%
12 / 12 / 6 / 100% / 0 / 0% / +100%
13 / 10 / 5 / 42% / 7 / 58% / -16%
14 / 8 / 4 / 40% / 6 / 60% / -20%
15 / 14 / 7 / 88% / 1 / 12% / +76%
*Flood Year
** Predators introduced
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Important terms:
· Habitat – place that provides shelter and food
· Niche – an organism’s role in its environment (ie: its place in a food web)
· Population – total # of one type of organism in a specific area
· Birth rate - # of births/total population from previous year
· Death rate -# of deaths/ total population from previous year
· Growth rate – (Birth Rate + Immigration Rate) – (Death Rate + Emigration Rate)
· Carrying capacity – total # of individuals an environment can hold.
· Exponential growth – constant growth
· Logistic growth curve – shows growth slowing or stopping after exponential growth
· Limiting factors – factor that causes population growth to decrease L
VI. Conclusion
Conclusion - FOLLOW THE WRITING CONCLUSIONS TEMPLATE and address the questions
Reflection Questions (these will help you discuss your findings “#3” on your template
1. Was there a noticeable pattern in your data? If so, describe it.
2. Explain how this simulation relates to biogeochemical cycles.
3. What were the limiting factors for population growth in this simulated ecosystem? Can these factors change over time?
4. Ecologists have found that no organism can experience indefinite exponential growth, yet the human population has experienced exponential growth for hundreds of years. How have humans modified the limiting factors of our population growth?
# 5 ….Explanations…… Describe reasons for the fluctuation of the population.