Unit 3 Biology

Part I

Abiotic factors Determining chance of species survival

Introduction

Different organisms live in a specific place in the biosphere called their habitat . Through the course of evolution , species have adapted to their environment by growing certain physical structures or developing certain characteristics . Factors such as availability of resources (such as light intensity , water availability and others ) contribute to the success of survival among species in the biosphere (Regents prep 2003 . Also , biotic relationships (such as competition , mutualism and others ) interact to the dynamics of species survival

Certain species of

plants grow abundantly in certain areas only of the biosphere . Some grasses grow abundantly in area where there is ample source of sunlight , but does not grow within forest beds where sunlight is scarce . In the same way , succulent herbs and vines are not commonly seen in dry area like the grassland

This exercise aims to characterize the effect of light intensity to the survival of grassland monocots

Hypothesis

Limit in the availability of resources would cause decrease in species productivity and may reduce their chance of survival . For plants that are adapted to direct sunlight exposure may not be able to survive when placed in an environment where there is less amount of light

Methods

For this experiment , effects of changes in lighting condition to grassland plant will be tested . To do this , find a grassland area (or any area that are exposed to direct sunlight most time of the day ) and select species of low growing monocots . The area should be occupied dominantly by a single species in to make easy observation Measure six feet by six feet (6 x 6 ft ) working area . Using small peg and nylon string mark the boundary and divide the working area into four equal quadrants . Tag the quadrants as area I , II , II and IV as shown in figure 1

I II

III IV

Figure 1 . Working quadrant in grassland area

Using long sticks and cheesecloth (or any material that would cast greater shadow , make a tent over quadrant III and IV making sure that quadrant I and II are not shaded . The tent will simulate shaded condition and limit sunlight exposure for species in quadrant III and IV , while ensuring that other condition such as , humidity , mineral and water contents of soil and interacting species (insects and other plants ) are held constant . In making the canopy , leave at least half foot (0 .5 ft ) gap above the tip of the grass so that air can circulate in the area and will not cast shadow in area I and II when direction of sunlight changes . Quadrant I serve as the control while quadrant II serves as a duplicate for the control . Quadrant III is the experimental and quadrant IV is the duplicate

Make a table and list the initial condition of the selected grass species found in all quadrants . Take note of the time observation was made and the condition of the environment such as temperature of the surrounding air...