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Environmental Science Table of Contents

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Lab 3 Biodiversity

Biodiversity

Concepts to Explore

• Biodiversity

• Species diversity

• Ecosystem diversity

• Genetic diversity

• Natural selection

• Extinction

Introduction

Biodiversity, short for biological diversity, includes the genetic variation between all organisms, species, and populations, and all of their complex communities and ecosystems. It also reflects to the interrelatedness of genes, species, and ecosystems and their interactions with the environment. Biodiversity is not evenly distrib- uted across the globe; rather, it varies greatly and even varies within regions. It is partially ruled by climate, whereas tropical regions can support more species than a polar climate. In whole, biodiversity represents variation within three levels:

• Species diversity

• Ecosystem diversity

• Genetic diversity

It should be noted that diversity at one of these levels may not correspond with diversity within other levels. The degree of biodiversity, and thus the health of an ecosystem, is im- pacted when any part of that ecosystem becomes endan- gered or extinct.

The term species refers to a group of similar organisms that reproduce among themselves. Species diversity refers to the variation within and between populations of species, as well as between different species. Sexual reproduction criti- cally contributes to the variation within species. For exam- ple, a pea plant that is cross-fertilized with another pea plant can produce offspring with four different looks! This genetic mixing creates the diversity seen today.

Figure 1: There are more than 32,000 species of fish – more than any other vertebrate!

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Biodiversity

Ecosystem diversity examines the different habitats, biological communities, and ecological processes in the biosphere, as well as variation within an individual ecosystem. The differences in rainforests and deserts represent the variation between ecosystems. The physical characteristics that determine ecosystem diversity are complex, and include biotic and abiotic factors.

? Did You Know...

A present day example of natural selection can be seen in the cray- fish population. The British crayfish are crustaceans that live in rivers in England. The American crayfish was introduced to the same bodies of water that were already populat- ed by the British crayfish. The American crayfish are larger, more aggressive and carry an infection that kills British crayfish but to which they are immune. As a re- sult, the British crayfish are de- creasing in number and are ex- pected to become extinct in Britain within the next 50 years. Thus, the American crayfish have a genetic variation that gives them an ad- vantage over the British crayfish to survive and reproduce.

The variation of genes within individual organisms is genetic diversity. This can be measured within a species as well as between species. It plays an important role in survival and adaptability of organisms to changing environments.

Diversity is also influenced by natural selection, the key mechanism of evolution. The process of natural selection describes competition be- tween individual species for resources such as food and space (habitat). Genetic variations among species provide an advantage over other species if those variations result in an ability to survive and repro- duce more effectively.

Evidence that supports the theory of natural selection include the fossil record of change in earlier species, the chemical and anatomical simi- larities of related life forms, the geographical distribution of related spe- cies, and the recorded genetic changes in living organisms over many generations. Take for example, homologous structures among different species, such as the wing of a bird and the forearm of a human. These structures provide evidence that embryologically similar structures can give rise to different functions based on the needs of the organism. Note that natural selection does not try to explain the origin of life but rather the later evolution of organisms over time.

Biodiversity is important to the process of evolution because it provides the framework on top of which natural selection can occur. As dis- cussed above, natural selection determines the genetic fitness, an or- ganism's genetic contribution to the next generation, of an organism.

Natural selection occurs by selecting one trait as "more advantageous" in a certain environment than anoth- er. The root of this selection is biodiversity.

Species extinction is not new; species have been evolving and dying out since life began. Now, however, species extinction is occurring at an alarming rate, almost entirely as a direct result of human activities. Sci-

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Biodiversity

entists recognize five major mass extinctions in the Earth’s history. The extinctions are measured in terms of large groups of related species, called families. The five mass extinction episodes occurred because of major changes in the prevailing ecological conditions brought about by climate change, cataclysmic volcanic erup- tions, or collisions with giant meteors. The sixth mass extinction appears to be in progress now, and the pri- mary cause is environmental change brought about by human activities. Some examples of species on the “endangered” list are the ivory billed woodpecker, amur leopard, javan rhinoceros, northern great whale, mountain gorilla, and the leatherback sea turtle.

Figure 2: The amur leopard is at risk of extinction.

Loss of an individual species can have various effects on the remaining species in an ecosystem. These ef- fects depend upon the how important the species is in the ecosystem. Individual species and ecosystems have evolved over millions of years into a complex interdependence. If you remove enough of the key spe- cies on which the framework is based, then the whole ecosystem may be in danger of collapsing. Regardless of a species’ place in the ecosystem, it is important for humans to take care of the world around us. As peo- ple become more aware of how their actions impact all living things they can make adjustments in an effort to preserve life on all levels.

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Biodiversity

There are many activities that humans take part in that impact the environment and biodiversity. The exhaust from automobile and aircraft travel as well as smoke stacks from industrial plants are the leading causes of air pollution, which can have harmful effects on natural resources and organisms. Two other important factors which can have an effect on biodiversity are overpopulation and affluence. Overpopulation means that there are more people than resources to meet their needs. As people become more affluent there is an increase in per capita resource utilization. All of these factors contribute to overharvesting, habitat degradation, and in- creased pollution which threaten biodiversity.

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Biodiversity

Demonstration 1: Interdependence of Species

In this lab, you will use the information provided above to demonstrate how the presence or absence of one species can affect the others in an ecosystem. Follow the procedure below to complete Demonstration 1 on the interdependence of species.

Materials

5 different colored beads:

White bead represents lichen

Orange bead represents trees

Red bead represents flowers

Yellow bead represents bees

Blue bead represents humans

Lichens

Lichens play a part in the creation of soils from which plants can obtain nutrients. Like all living organisms, lichens need nutrients and energy to grow. Nutrients may be obtained from the air (including dust), water, and from the substrate organisms grows on. They obtain energy through photosynthesis, which is the role of the algal partner. They may also be incidentally fertilized by bird and insect dung.

Trees

Most trees, flowers and plants depend on soil for food (nutrients). Fruiting trees depend on bees as one means of pollination.

Flowers

Forest flowers and plants depend on trees for shade and wind protection as well as soils for nutri- ents.

Bees

Bees depend on flowering plants and trees for food.

Humans

Humans depend upon bees for honey and more importantly for fruit from trees they pollinate.

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Biodiversity

Procedure

1. Download the Week 3 Lab Reporting Form from the course instructions. As you conduct the demonstra-

tion and the experiment, record any hypotheses, observations, and data on that form.

2. Place all of the beads in a bag.

3. Randomly choose 4 beads from the bag.

4. Identify each bead by the color code in the materials box.

5. Record which species is missing in Table 1 on the Week 3 Lab Reporting Form.

6. Repeat this process 3 more times (or until 3 different beads are taken out of the diagram). Be sure to rec-

ord which species is missing from each round in Table 1 and answer the Post-Lab questions on the Week

3 Lab Reporting Form.

Experiment 1: Diversity of Plants

Variations in growing conditions, climate, and numerous other factors can alter the biodiversity of an ecosys-

tem. As such, biodiversity is often utilized as an indicator of ecosystem health. In this experiment, you will

grow a sample of seeds under two different conditions. Follow the procedure below to complete Experiment 1

on the diversity of plants.

Materials

Seed mixture (zinnia, marigold, morning glory,

cosmos, and ryegrass)

Potting soil

(2) 5.5 x 3.5 in Peat pots

10 mL Graduated cylinder

*Water

*You must provide

Procedure

1. Read through the Experiment 1 procedure and then record your hypothesis on the biodiversity of seeds

grown under two separate conditions on the Week 3 Lab Reporting Form.

2. Fill your pots loosely with soil until the soil is approximately 1 inch from the top.

3. Pour approximately 40 mL of tap water into your pots (less if the soil becomes very wet).

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Biodiversity

4. Lightly scatter your seeds on top of the soil in each container. This should be a random assignment of

seeds to each pot.

5. Press each seed down about ½ inch into the soil.

6. Place one pot in a sunny, indoor location (on a window sill that receives sunlight) and the second pot in a

shaded, indoor location (away from all windows, this pot should not be placed in the dark, just away from

direct sunlight).

7. Observe and water your seeds every day until you see them grow. These seeds will germinate quickly (3

- 7 days).

8. Complete Table 2 on the Week 3 Lab Reporting Form after approximately 1 - 2 weeks (or when you see

a reasonable amount of plant growth in the peat pot) and answer all Post-Lab Questions on the Week 3

Lab Reporting Form. Table 3 (provided on the following page) provides pictures of the germinated seeds

to help you determine when you should begin entering data, and what each plant looks like.

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Weather and Climate Change

Table 3: Picture and Description of Seedlings Grown from Seed Mixture

Species Observed Picture Description

Zinnia

Short stems with dark green, rounded leaves

Marigold

Stems are shorter than cosmos with long skinny leaves (but wid- er than the cosmos leaves) with rounded tips

Morning Glory

Tall stems with elephant ear shaped leaves

Cosmos

Tall stems with long, pointed leaflets; a lighter green leaf com- pared to the marigold

Ryegrass

Long, skinny strands of green grass

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Appendix Good Lab Techniques

Good Lab Techniques

Good Laboratory Techniques

Science labs, whether at universities or in your home, are places of adventure and discovery. One of the first things scientists learn is how exciting experiments can be. However, they must also realize science can be dangerous without some instruction on good laboratory practices.

• Read the protocol thoroughly before starting any new experiment. You should be familiar with the action required every step of the way.

• Keep all work spaces free from clutter and dirty dishes.

• Read the labels on all chemicals, and note the chemical safety rating on each container. Read all Material Safety Data Sheets (provided on www.eScienceLabs.com).

• Thoroughly rinse lab ware (test tubes, beakers, etc.) between experi- ments. To do so, wash with a soap and hot water solution using a bottle brush to scrub. Rinse completely at least four times. Let air dry

• Use a new pipet for each chemical dispensed.

• Wipe up any chemical spills immediately. Check MSDSs for special handling instructions (provided on www.eScienceLabs.com).

• Use test tube caps or stoppers to cover test tubes when shaking or mixing – not your finger!

A B C

Figure 1: A underpad will prevent any spilled liquids from contaminating the sur- face you work on.

Figure 2: Special measuring tools in make experimentation easier and more accu- rate in the lab. A shows a beaker, B graduated cylinders, and C test tubes in a test tube rack.

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Good Lab Techniques

• When preparing a solution, refer to a protocol for any specific instructions on preparation. Weigh out the desired amount of chemicals, and transfer to a beaker or graduated cylinder. Add LESS than the required amount of water. Swirl or stir to dissolve the chemical (you can also pour the solution back and forth between two test tubes), and once dissolved, trans- fer to a graduated cylinder and add the required amount of liquid to achieve the final volume.

• A molar solution is one in which one liter (1L) of solution con- tains the number of grams equal to its molecular weight.

For example:

1M = 110 g CaCl x 110 g CaCl/mol CaCl

(The formula weight of CaCl is 110 g/mol)

Figure 3: Disposable pipettes aid in ac- curate measuring of small volumes of liquids. It is important to use a new pi- pette for each chemical to avoid con- tamination.

• A percent solution can be prepared by percentage of weight of chemical to 100ml of solvent (w/v) , or volume of chemical in 100ml of solvent (v/v).

For example:

20 g NaCl + 80 mL H2O = 20% w/v NaCl solution

• Concentrated solutions, such as 10X, or ten times the normal strength, are diluted such that the final concentration of the solution is 1X.

For example:

To make a 100 mL solution of 1X TBE from a 10X solution:

10 mL 10X TBE + 90 mL water = 100ml 1X TBE

• Always read the MSDS before disposing of a chemical to insure it does not require extra measures. (provided on www.eScienceLabs.com)

• Avoid prolonged exposure of chemicals to direct sunlight and extreme temperatures. Immediately se- cure the lid of a chemical after use.

• Prepare a dilution using the following equation:

c1v1 = c2v2

Where c1 is the concentration of the original solution, v1 is the volume of the original solution, and c2 and v2 are the corresponding concentration and volume of the final solution. Since you know c1,

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Good Lab Techniques

c2, and v2, you solve for v1 to figure out how much of the original solution is needed to make a cer- tain volume of a diluted concentration.

• If you are ever required to smell a chemical, always waft a gas toward you, as shown in the figure below.. This means to wave your hand over the chemical towards you. Never directly smell a chemical. Never smell a gas that is toxic or otherwise dangerous.

• Use only the chemicals needed for the activity.

• Keep lids closed when a chemical is not being used.

• When diluting an acid, always slowly pour the acid into the water. Never pour water into an acid, as this could cause both splashing and/or an explosion.

• Never return excess chemical back to the original bottle. This can contaminate the chemical sup- ply.

• Be careful not to interchange lids between different chemical bottles.

• When pouring a chemical, always hold the lid of the chemical bottle between your fingers. Never lay the lid down on a surface. This can contaminate the chemical supply.

• When using knives or blades, always cut away from yourself.

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