Essay on Student: Ecology and Species

Submitted By bbhsin
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ENV 1020 Summer 2012: Review for Exam 3

General – the test will be ~35 - 45 multiple choice and/or matching questions. This class is focused on general concepts and you do not have to get extremely detailed. The level of detail discussed in class and in the summary section at the end of each chapter will be sufficient. If you need to know specific examples (e.g., rain shadows, photosynthesis equation), it is stated below. If your notes and textbook do not explain things adequately for you, definitely look a topic up on the internet. Again, watch/read the links I added to blackboard, they will help.

Lecture 11 – Predation and Parasitism (continued)
▪ Know the characteristics of predation and parasitism. How are they (slightly) different? o Predation – When one organism eats another, usually kills the organism, one time thing. Includes herbivory. o Parasitism – One organism feeding on another organism, similar to predation.
▪ What is a parasite? - When one organism lives on or within another organisms to survive. Parasite benefits at the expense of another. Usually does not kill the host.
▪ What is a vector? – A host (organism) that is the transporter of a parasite to the primary host. o Ex: Schistosomiasis – Snails are the vectors the larva from the egg penetrates them. When they shed the release it into the water and the cercarie penetrates the human’s skin when they come in contact with the water. The snail is the vector or transport unit in this case.
▪ What adaptations have parasites made to better survive?- Parasites better survive by altering their hosts behavior. (something they usually wouldn’t do. o Ex: cricket and hairworm. When the hairworm wants to reproduce (in the water) they make the cricket jump in and drown. o Infected amophipods swim towards the light and gets eaten by a predator and the parasite will mature inside the predator.
▪ BE able to discuss host-parasite co-evolution – It’s when the host and parasite develop adaptions to build immunities against each other. A host may develop their immune systems to prevent the parasite from growing within them and the parasite may find new ways to enter the host’s body.
▪ Why is it (usually) more advantageous for parasites to not kill their hosts? – Parasites can either don’t hurt the host too much and grow slowely. ( most cases) Or kill the host by growing rapidly over a short period of time but kill the host (lose your home and food). Most tread lightly. This approach leads to longer more sustainable growth.
▪ Three stages of development: o Parasitism – one side benefits at another’s expense o Commensalism- one side benefits without effecting another’s well being o Mutualism – Both sides benefit.
▪ Why are parasites of global concern and interest in terms of health? o Parasites pose a lot of health issues, especially in third world countries
▪ Repeated exposure to schistosomes causes Egytian life expectancy to be mid 40s
▪ Millions of children each year dies from malnutrition and parasites
▪ Malaria kills 600-1.2 million lives.
▪ Plagues caused by fleas
▪ Live stock and pets. o Also interesting some benefits can come from parasites o Hookworms whipworms reduce auto-immune diseases
▪ Allergies, asthma, inflammation etc.
▪ Shark parasites absorb toxins o A lot of debate.

Lesson 11b - Mutualisms
-- Know what mutualism – When two organism interact with each other biologically and each organism increase their fitness as a result. is, facultative – When two organisms derive benefits from each other but do not fully depend on each other. and obligate mutualisms – Organisms depend on each other to survive.
-- Know how the following mutualisms work – the species involved, and what each species provides to and receives from the other: -- mychorrhizal fungi – Is a fungus that grows on the roots of plants. They have better absorption capabilities that allow the plants to absorb more mineral nutrients and water.