Quiz 1

1. Consider the hierarchy of organization for the environment (population, community, etc) in answering the following idea.  Discuss the role of observation and inference at each of the major hierarchical levels.

Organism, population, community, ecosystem, biosphere

Outside of a scientific setting, many people have difficulty distinguishing the difference between observation and inference. However, when used to categorize and explore our surroundings, observations and inferences are two very separate categories.

On an organismal level, it is important to make astute observations of the subject, either living or deceased, in order to make inferences about the subject’s behavior and skill set. Describing an organism with inferences could lead to incorrect conclusions about its behavior. When describing populations and community, the same principle applies. Using inferences as observations could lead to incorrect conclusions about interactions between species and organisms, thus arriving at false information and possibly changing what we think we know about past populations and communities.

When describing ecosystems and the biosphere, it is even more so important to first list observations in order to correctly make inferences about changes in climates, populations, and learn about the major weather trend. Applying these observations will lead to correct inferences, and allow for a better learning environment.

2.  Ecologists distinguish between climate and weather.  Photosynthetically active radiation is critical to many organisms on the surface of the Earth.  Discuss how this resource varies with season in the temperate northern latitudes, the northern polar latitudes, and at the equator.  How does this variation affect the distribution of plants, animals and microbes in those areas?

Organisms relying on photosynthetically active radiation need certain wavelengths from the sun in order to produce sustenance to maintain life. Each of the three latitudes, the temperate northern latitude, the northern polar latitude, and the equator, hold different levels of sunlight, and also have different amounts of sunlight per year. Because each location is unique to the level of sunlight received to the organismal level, distribution of organisms varies highly amongst the areas.  

The equator has the most constant amount of sunlight, thus allowing for the largest amount of organisms the environment can sustain. The Temperate Northern Latitudes and the Northern Polar latitudes hold fewer organisms due to restrictions from sunlight, respectively. Thus, each location has a more wide spread and more sparse distribution than an area near the equator.

3.  You performed an experiment with boats to examine the notion of buoyancy and cohesion.  You were limited to a piece of paper.  How would your results differ with the same surface area of balsa wood?  Of aluminum foil?  Explain the reasoning for your response.

A piece of paper is far less sturdy than the same surface area of a balsa wood boat, thus would be able to hold far less than a boat of balsa wood. The boats would most likely be able to float equally as well, however; when placing small objects, such as pennies, the wooden boat would be able to hold far more of the object than the paper boat. An aluminum foil boat would be much more malleable in the water, and if an equal boat were to be made of this material, would float just as well as the paper or wood boat. However, when placing objects in the boat, the foil would most likely bend and sink soon after place the objects. This is because the foil is a relatively heavy material, however, it is not completely solid like the balsa wood.

4.  You investigated the length of pine needles for one of your experiments, measuring 80 needles.  Look online or in a tree identification book to determine the species you examined.  How do your observations fit with those described for the species for needle length?  How would you design an experiment to determine the effects of environment on needle length?  Be sure to state your assumptions.

It is possible our needles came from a Slash Pine. This is a pine native to Florida, borne with two needles sheathed in a fascicle like the needles we observed, and with needle length near to the averages taken from our tree. The average online number is about 22 cm, where our average was about 26 cm for the needle length.

In order to design an experiment to determine effects of environment on needle length, several young pines would need to be split into even groups. One group would need to be the control group, placed in its natural environment. The other groups would need to simulate the natural environment of the tree all the way down to one variable. The variables would most likely be sunshine, water levels, wind levels, and humidity levels. With more or less of the variable than usual natural environment offers, the tree needles could become shorter to allow for more energy to go into seed production and tree protection. The largest factor would most likely be amount of sunshine, without enough sunshine the tree would not be able to produce sustenance for survival.  

5.  You have examined the resource use by leaf miners.  Instead of an ocular micrometer, you had access to a ruler for measuring the tunnel.  How might efficiency change for miners on oaks?  On red mangroves?  On apple trees?  How would you set up an experiment to test your ideas?

Efficiency of the leaf miners could change through calculations when switching to an ocular micrometer from a ruler strictly from higher accuracy. The leaf mine on the leaf I examined had a width ranging from 1 mm to 1.5 mm. Using an ocular micrometer, I would probably be able to examine the leaf more accurately and find the width to a more accurate decimal place.

Leaf miners feasting on different trees would mean different efficiency rates. There are hundreds of species of leaf miners, most feeding on specific trees, however; for the purpose of this explanation I will assume one species of leaf miner is feasting on oak, red mangroves, and apple trees.

Oaks, red mangroves, and apple trees all have different leaves with different thicknesses. Leaf miners are small insect larvae that feast on the leaves of trees by tunneling across the surface.  Because of the varying thicknesses, the leaf miners may create such a wide tunnel for each leaf. Apple trees have the thinnest leaves, then oak trees, then red mangroves. For each of these leaves, the leaf miner would need to make a thinner, and probably shorter, tunnel respectively. Holding a few of each of the trees in equal environments, and releasing the appropriate miners to feast upon them could test this. The miners would have until they change into worms to complete the experiment.