Measure species distribution using mathematical way of expressing the amount of biodiversity and species distribution in a community.
Materials: Pen Paper Procedure:
1. This is an outdoor activity. Go to the area designated by your teacher.
2. Record the number of different species of trees present in the area. (It is not necessary to know their names, just make sure that they differ by species.) Record this number in your data table.
DATA TABLE Number of species Number of runs Number of trees
3. Go to the designated area again. This time, make a list of the trees by assigning each a number as you walk by it.
4. Place an X under Tree 1 on your list. If tree 2 is the same species as Tree 1, mark another X under Tree 1. Continue to mark an X under the trees as long as the species is the same as the previous one.
DRAFT
March 31, 2014
Learner’s Module7 5. When a different species is observed, mark an O under that tree on your list. Continue to mark an O if the next tree is the same species as the previous. If the next tree is different, mark an X.
6. Record in your data table:
a. The number of “runs”. Runs are represented by a group of similar symbols in a row. Example – XXXXOOXO would be 4 runs (XXXX – 1 run, OO – 1 run, X – 1 run, O – 1 run).
b. The total number of trees counted.
7. Calculate the Index of Diversity (I.D.) using the given formula: Index of diversity = Number of species x number of runs Number of trees
Guide Questions:
Q 1. Compare how your tree I.D. would be different in a vacant lot than that in a grass lawn. Explain your answer. _____________________
______________________________________________________________ Q 2. If humans were concerned about biological diversity, would it be best to have
a low or high I.D. for a particular environment? Explain your answer. ______________________________________________________________
Key Concepts
Population pertains to the number of organisms of the same species living in a certain place.
Biodiversity refers to the variety of life in an area.
Communities with many different species (a high index of diversity) will be able to withstand environmental changes better than
DRAFT
March 31, 2014
Learner’s Module8
In a balanced ecosystem, organisms need a balanced environment. A change in population sizes may be due to factors affecting the environment. Why is it that populations do not increase without end?
Look at Figure 3. This is an area in Calauit, Palawan, that is set aside as a park preserve, and no hunting is allowed in the park. A number of animals like giraffe and zebra are placed in the area. There are plenty of plants to serve as food for the giraffe and zebra population. The herd of giraffe and zebra are assumed to be healthy and begin to multiply faster than expected. Predict what will happen if the giraffe and zebra population continues to increase in the park area.
You will work on the next activity to help you understand changes in population, factors affecting population growth and size, and learn about the needs and characteristics of a population.
DRAFT
March 31, 2014
Learner’s Module9
Activity 2 Measuring Population Density
Objective:
Determine the pattern of population distribution using mathematical formula
Compare the distribution patterns of the different populations. Materials:
Ruler
Pencil & Paper Procedure:
118cm
4. On a sheet of paper, prepare a table to record the data for population density.
Table 1 Population Density
Population name Number of organisms Density
5. Calculate the density of each population. Record it in the table.
Guide Questions:
Q 3. Compare the distribution patterns of the three populations.
___________________________________________________________ 20 cm
Bermuda grass Clover Lilies Figure 4.
1. Study the three patterns of population distribution in Figure 4.
2. Using the given formula for computing population density,
calculate the density of each population.
Density = number of individuals Size of area
3. Count the total number for each population. Record the
DRAFT
March 31, 2014
Learner’s Module10 Q 4. Which population has the greatest density?_______________________
Q 5. Infer from recorded data from the possible causes for the differences in the population density.
Q 6. What conditions could change the density of any of the population.
_______________________________________________________________ Q 7. Describe how a population’s density can be used to learn about the needs and characteristics of that population.
_____________________________________
Populations can be of the same size, but they may have different densities. When we consider the number of individuals per unit area, we are referring to the density of the population. Differences in population density in any community may be attributed to many factors. Population sizes change when new members move into the
ecosystem. They decrease when members move out of an ecosystem. The birth rate and death rates can also affect a population’s size. Anything that limits the size of a population like certain environmental conditions are called limiting factors. Limiting factors keep a population from increasing in size and help balance an ecosystem. Examples of limiting factors are the availability of food, water, and living conditions. Light, temperature and soil nutrients are also limiting factors because they help determine the types of organisms that can live in an ecosystem. The maximum population size an environment can support is called its carrying capacity. If the population size rises above the carrying capacity, organisms die because they cannot meet all their needs.
Q 8. How are limiting factors related to population density?
__________________________________________________________ Key Concepts:
Population sizes vary among organisms. They change with the number of births and when they move into an ecosystem. They also change when members die or move out of an ecosystem. Limiting factors are environmental conditions that keep a
population from increasing in size and help balance ecosystems. The carrying capacity is affected by changes in the environment.
DRAFT
March 31, 2014
Learner’s Module11
Life depends on life. Animals can not exist without green plants. Living things create niches for other living things. But what happens if the living conditions of these organisms are not ideal for their survival? What do you think are the major causes of species extinction?
Work on the next activity which demonstrates the probable causes of species extinction.