Plant Transpiration Lab

DATA TABLE:

	normal	with fan	with heater	with lamp
arrowhead	3.6	7.5	6.6	4
coleus	0.9	6	3.9	3
devil's ivy	2.9	4.6	4.1	3
dieffenbachia	4.1	7.7	6	3.9
english ivy	1.8	5.1	3.2	2.1
geranium	1.2	4.7	5.8	2.4
rubber plant	4.9	8.4	6.8	4.3
weeping fig	3.3	6.1	4.9	2.5
zebra plant	4.2	7.6	6.1	3.2

1. Describe the process of vascular transpiration in plants.

First, water is absorbed through the roots of the plant. This happens with the help of three factors, osmosis, cohesion, and adhesion. Cohesion: the water droplets stick together. Adhesion: The water droplets stick to the xylem  Both cohesion and adhesion occur due to the polarity of a water molecule. Osmosis: the water moves from an area of high concentration (ground) to low concentration (up to the plant). Excess water, i.e. water not used in photosynthesis, in the plant leaves can get evaporated through the stomata, which are used for gas exchange.

2. Describe any experimental controls used in this investigation.

One control is to test all the plants rate of transpiration without any added factor, i.e. light, heat, or fan. Another control is the room remaining a constant temperature throughout the experiments. One more is the air, they are all in the same location so the air will be the same for each experiment. Time is also a control, they each sat for the exact same amount of time.

3. What environmental factors that you tested increased the rate of transpiration? Was the rate of transpiration increased for all plants tested?

For each plant, the presence of a fan caused there to be an increase in the rate of transpiration, so in nature this would be the equivalent of wind, or a constant flow of air. A heater also caused an increase in the rate of transpiration, which is the equivalent of high temperatures in nature. In 4/9 plants there was an increase in transpiration with the presence of light, however the other 5/9 had a decrease.

4. Did any of the environmental factors (heat, light, or wind) increase the transpiration rate more than the others? Why?

In all but 1 plant, the rate of transpiration was highest with the presence of wind. I hypothesize that this is because the constant air flow keeps the water concentration in the air relatively low so osmosis causes more water to continue to be evaporated because it is moving to an area of low concentration. If there is no wind, the air will increase its water concentration, and osmosis won't occur anymore.

5. Which species of plants that you tested had the highest transpiration rate? Why do you think different species of plants transpire at different rates?

The rubber plant had the highest rate of transpiration. I think that different species of plants transpire at different rates because based on the different environments they have adapted to, they have different water needs. For example, plants in a very hot, desert-like environment will have lower rates because they need to hold onto as much water as possible. However, plants in a rain forest environment can have higher rates because there is a constant influx of new water from the roots.

6. Suppose you coated the leaves of a plant with petroleum jelly. How would the plant's rate of transpiration be affected?

The petroleum jelly would hinder the plant's ability to transpire, because oil-like products block moisture from leaving the surface. In humans, this occurs in products such as Chapstick and lotion.

7. Of what value to a plant is the ability to lose water through transpiration?

It is very valuable to a plant because having too much water can drown the plant, or flood the leaves and cause them to burst. At the same time, losing too much would cause it to dry out and not be able to perform cell functions, i.e. photosynthesis.

Plant Hormones

     Auxin is a hormone that controls plant cell growth. This allows for many things to happen, two being phototropism and root/stem growth. In the case of phototropism, there is sunlight on one side of the plant. This triggers auxin to excrete in the shaded side. Auxin causes cell walls to elongate, eventually leading to longer cells. When this happens, the plant will lean towards the sun. This is important because it will increase the amount of sunlight a plant is getting, which will lead to more photosynthesis, which will create glucose and oxygen. This glucose can then be broken down in cell respiration to provide the plant with ATP. This glucose will also go down the tissue called phloem to the roots of the cell to provide nutrition in the form of glucose and fructose, which can combine to create sucrose. This sucrose is the sap you see on most plants.

Auxin has created elongated cells on the shaded side causing the plant to lean towards the sun
http://bio1152.nicerweb.com/Locked/media/ch39/39_05PhototropismExper.jpg

A plant in which this phototropism has occurred
http://cdn.phys.org/newman/gfx/news/hires/2013/howdoplantsg.jpg

The other example was root and stem growth in plants. As we have observed thus far in our lab that Siri and I did, no matter which way the seed is originally facing, the roots will grow down and the stem will grow up. The force of gravity tells the plant which way the ground is, and this causes auxin to be released into the roots and stem. In the roots, it will inhibit elongation on one side to cause a downward bend. In the stem, it will cause growth on one side to cause an upward bend. This entire process is called gravitropism.

Seeds undergoing gravitropism after sprouting
http://botit.botany.wisc.edu/Resources/Botany/Root/+%20gravitropism%20MC%20.jpg

Plant undergoing gravitropism
http://www.visualphotos.com/photo/1x8469278/gravitropism_geotropism_BJ1486.jpg

     Abscisic Acid is a plant hormone that slows germination. This is very important to plants, especially those that live in conditions that are very harsh, for example the desert. An excess of abscisic acid would require a lot of water to be washed away, therefore many larger desert plants, such as cacti, have a lot of abscisic acid on the seed. This means that in order for it to begin germination, there must be a sufficient amount of water, therefore the plant's growth can be sustained. This usually will occur after the rainy season. A low amount would be present in smaller plants, like desert grasses. They don't live very long and require less water, so therefore a small amount of water would be enough to wash the acid away and begin germination.

A cacti, which is an example of a plant that requires a lot of water to germinate.
http://fvcgeography.files.wordpress.com/2011/10/cactus72.jpg

     Ethylene is a gas that is naturally produced by fruits that cause them to ripen. This means that if one fruit ripens, the others will ripen quickly. This was an evolutionary benefit, as it makes the plant get eaten more quickly by an animal which means its seeds can be spread more quickly.

A plant that has ripened due to Ethylene gas
http://www.rsc.org/chemistryworld/sites/default/files/upload/x0612CW_NIBS_pg004-300.jpg

Botany of Desire

Co-evolution: Bee pollinates the flower, flower provides the bee with food
http://www.bee-hexagon.net/files/image/beeFlowerCassino.jpg. 

Apple's sweet flavor causes humans to plant apple trees
http://media.onsugar.com/files/2010/11/45/1/192/1922195/99c5d0ec27c80142_89697806.preview.jpg

Tulip's beauty causes humans to want to plant them
http://hdwallpapersearly.com/wp-content/uploads/2014/03/tulips-wallpaper-7.jpg

The potatoes' flavor makes humans want to plant them
http://upload.wikimedia.org/wikipedia/commons/a/ab/Patates.jpg

Marijuana's intoxicating effects makes humans plant them
http://www.bestwallpaperdesign.com/wallpaper/30873-weed-wallpaper-hd.html/weed-wallpaper-hd-7

Predatory Prey

Predator Prey Lab

     The goal of this lab was to demonstrate the relationship between predatory and prey. In this graph you can see many things. The first is that there must be significantly more rabbits than wolves. This is due to the 90% of energy that is lost between each trophic level. Therefore, there must be 1/10 as many wolves as there are rabbits. You can also see here that when the prey overshoots the carrying capacity, its numbers will drop rapidly. This will also cause a the wolf population to drop because they have no food left. As you can see towards the right of the graph, the rabbit population will then once again increase, and the wolf population will follow. You can also see that it took about 3 generations for a wolf to survive because there were not enough rabbits to sustain one wolf. Once there were enough rabbits, the wolf population was able to grow.
     We had the snow terrain, so therefore more white rabbits survived than green or yellow. This is because the white rabbits have a mutation that allows them to blend into the snow. This is called survival of the fittest. As the green and yellow die off, only white will survive and reproduce. Over a long period of time this would lead to an all-white rabbit population. If rapid warming, however, were to occur, then the snow would melt and the rabbit population would quickly die off because they were evolved to their specific surroundings.

Deforestation

BREAKING NEWS:

There has been a huge increase in deforestation. Last week a new timber company came and cut down large sections of the boreal forest in Canada. One major effect this had is known as the “edge effect”. This creates edges of the forest in area that were previously deep forest. This causes an increase of sunlight in those areas and a rise in temperature. Organisms that previously could live in these deep forest areas are unable to survive once they become edges.

Photo credit to Think Global Green

Another effect would be major habitat destruction. Many animals, such as squirrels, burrow in trees in the boreal forest, so this loss of habitat would be devastating.

Birds, however, would have a major increase in numbers, as it would be easier for them to find food without the cover of the trees. The birds can also easily build new nests in different trees, while the journey to another tree may be impossible for a small ground squirrel or other rodent. The bird population would thrive, likely causing a population overshoot and die out. 

Another devastating impact would be the loss of genetic diversity. Because areas of boreal forest are separated in ways they never have been before, animals will not be able to move from one area to the next, which causes a decrease of genetic variation. This decrease is devastating because it doesn't allow a population to rebound from disaster quickly.

Deforestation also releases a huge amount of CO2 which causes global warming. This warming would be disastrous for the boreal forest because the animals have developed to resist the cold conditions they live in. For instance this warming could melt all the snow, if it becomes very extreme, and the snowshoe hare population would quickly die back because when their fur changes color to white in the winter, that would no longer provide camouflage. Only the hares with a mutation in their genes so that their fur won't change colors would survive.

Photo credit to National Geographic

Works Cited                                                                                                          http://evolution.berkeley.edu/evosite/relevance/IIIA2Lowvariation.shtml

TRAVEL BLOG

     HEY GUYS! I recently took a trip to northern Canada to visit the boreal forests there. Canada has the second largest percentage of boreal forests in the world, Russia having the largest percentage. Before I took my trip I did a lot of research about the climate, abiotic and biotic factors, and about evolution that occurred in these areas. This is what I learned:

      The boreal forest is a forest located in the northern hemisphere in Russia, Canada, Alaska, Sweden, Norway, Finland, etc. The vast majority is in Russia, however 60% of Canada is covered by boreal forest.

Distribution_Taiga.png ‎(800 × 398 pixels, file size: 109 KB, MIME type: image/png) Author – GeForce3

In general, boreal forests, also known as Taigas, are characterized by their mixture of coniferous trees, such as pines, and deciduous trees and their extreme cold temperatures. 

Abiotic Factors

Abiotic factors are non-living characteristics, so for example soil type, climate, air quality, etc.

     The soil in boreal forests is a type of soil known as spodosol or podzol. This type of soil lacks nutrients, because the extreme cold doesn't allow organic material to decompose and supply the soil with nutrients. The soil tends to be extremely thin and young. The soil is also acidic due to the pine needles that fall from the trees, which hinders growth on the forest floor, and only very select mosses and lichens are able to grow. If parts of the forest are cleared, there are often more berries and mosses able to grow because the soil is less acidic because of the lack of pine needles.

     The climate in boreal forests is cold and wet. During the winter months, precipitation occurs as snow and in the summer it occurs as heavy rain. The forests are characterized by their long cold winters and short mild summers. The average low temperature is about -8 degrees fahrenheit and the high temperature about 70 degrees fahrenheit. Below is a graph of the average temperature (in fahrenheit) and rainfall (in inches) during each month.

Retrieved from http://cougarbiology.pbworks.com/f/nicgraph.png  

   
     The air in boreal forests has a high oxygen level because there are many trees which produce oxygen. During the summer there are roughly 20 hours of sunlight, however in the winter there are only about 4 hours. The thick forest provides a great amount of shelter for the organisms living in the forest.

http://naturescrusaders.files.wordpress.com/2010/05/boreal-forest-canada.jpg

Biotic Factors

     Producers

     Boreal forests have a mixture of coniferous trees, like pines, and deciduous trees. Coniferous trees are trees with cones and needles. Deciduous trees are trees that shed their leaves annually. Boreal forests also have a wide variety of shrubs, herbs and grasses. 

Photo by Marshall Sunberg

     Consumers

     Boreal forests have a large number of both primary and secondary consumers. Some primary consumers include rabbits, insects, deer, buffalo, goat, sheep, mice, and a wide variety of birds. Some secondary consumers include wolves, foxes, predatory cats, bears, and raccoons.

     

Photo by Tom W. Hall

      Decomposers

Decomposers are fungus and bacteria that break down dead plants and animals. In the forest there are many types of lichens and fungi. The decomposition occurs very slowly in boreal forests.


     Human Influences
Humans have been threatening boreal forests for two main reasons. The first being the desire to drill for oil in places that are covered by boreal forest, like parts of Alaska and Canada. This drilling would destroy the forest ecosystem. The second threat is logging in forests. These trees are slow growing and it would take hundreds of years to recover from that type that of damage.

Food Web

Picture from ecoplexity.org

Evolution

     You can see the evolutionary benefits that the animals of the boreal forest have adapted. For example, the snowshoe hare's coat changes color from brown to white in the winter to allow it to avoid the secondary consumers. They also have adopted unusually large paws to avoid sinking into the deep snow in the winter months.

     Other predatory animals such as the bear and wolf have developed thick coats to keep them warm in the winter. They also are very large to have more body heat.

Works Cited

http://theborealforest.wordpress.com/human-impact/

http://www.ducks.ca/assets/2012/06/nv15_bf.pdf

http://en.wikipedia.org/wiki/Boreal_forest_of_Canada

http://en.wikipedia.org/wiki/Boreal_forest

http://www.borealforest.org/world/world_species.htm