Ecology

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 * Chapter 51 Animal Behavior (Andrew, Jason, Supritha, Hannah) **

1. Explain at least three forms of animal communication. Chemical communication: form of communication in which specific chemical molecules serve as signals that are transmitted by one animal and received by another. i.e. male fruitflies olfactory systems allow them to receive the chemicals trasmitted by the female fruitflies.

Tactile communication: form of communication involving direct touching of animals

Visual communication: form of communication involving animals looking at each other, triggering visual signals

Supritha 2. Outline the process and details of imprinting. During the sensitive period, or critical period, imprinting can occur as the young imprint on their parent as they learn their species' usual behaviors. During the same time, the parent develops greater recognition of its offspring. A bond is formed (a pair-bond denotes a strong attachment), and a long lasting behavioral response to a certain object or individual is learned. This describes the learned aspect of imprinting, but there is also an innate aspect. The young's environment provides an imprinting stimulus which will be the object or individual to which the response will be directed; this is how the young know on whom or what to imprint.

Supritha 3. Explain one experiment to test the optimal foraging model.

4. List and explain the steps in animal mating.

5. What is the scientific/genetic basis behind animal altruism. Animal alturism is when one organism sacrifices itself for the well being of it's community. Scientists have found that animals are more likely to sacrifice themselves for animals that are closely related to them because it increases their populations fitness. William Hamilton hypothesized that natural selection favored altruistic acts, it is based on the cost, the benefit and the probability that a specific gene would be passed on. -Hannah


 * Chapter 53 Population Ecology (Gordie, Daniel, Emily, Jen) **

__Population density__ refers to the amount of people in a specified area. __Population dispersion__ is the pattern of how individuals are spaced within a certain geographic region. __Age structure__ relates the ages of individuals to others within the population.
 * 1) Distinguish population density, population size, population dispersion, and age structure of population.

Emily Halpern

Life tables show what the probability is that a person of a certain age will die before his or her next birthday. This helps infer the probability of surviving at any age and the remaining life expectancy for people of certain ages. It is best to construct them for men and women separately because they have different life expectancies and mortality rates. Survivorship curves shows the number of individuals surviving at each age for a given species. It is best to construct them for a group of individuals of roughly the same age, which can be found based on a life table. A reproductive table is an age-specific summary of the reproductive rates in a population. It is best separated into the different stages of reproduction and development. -JLM
 * 1) What kind of data do the different demographics (life table, survivorship curves, reproductive table) summarize? Explain each demographic and the best way to construct them.

A. __Exponential Population Growth (Geometric population growth)__ -Includes a population whose members all have access to abundant food and reproduce at their own rate -Population size will grow exponentially and increase at a constnat rate -Forms a J- shaped curve as population growth depends on N and Rmax, but takes into account both births and deaths in a large scheme of things **J- shaped curve is the characteristic that shows new populations that are introduced into a different environment and their interactions in the environment * Rmax =maximum rate for the species * N = population size * t = time * d = "change in __"__
 * 1) Show and explain the logistic and exponential models, including what each variable stands for.

(dN) __= Rmax N__ __ (dt) __

__ B. __Logistic Growth Model __ * K = carrying capacity (max population size that an environment can maintain) __ __ -Varies over space and time with the abundance of limiting resources such as shelter, water and refuge from predators __

__ - In this model, the per capita rate of increase approaches zero as the carrying capacity is reached __ __ - The logistic growth model is an expansion of the exponential population growth model, but adds an expression to reduce the per capita rate of increase as N increases. __ __ -The population growth rate will decrease dramatically as N approaches K __

(dN) __= Rmax N__ (K-N)__ (dt) K

Daniel Kogan


 * 1) Compare the evolution of semelparity versus iteroparity evolution. What two factors likely contribute to these evolutions?

Semelparity evolution includes organisms who are only capable of reproducing one time, often because the refproduction is fatal. An example of a semelparous organism is a pacific salmon. Pacific salmon live the majority of their life in the ocean, and then swim to freshwater where they then lay their eggs and die. Iteroparity evolution includes organisms who are capable of having multiple reproduction cycles and many offspring throughout their life. Humans are an example of Iteroparity evolution. The enviornment of a creature probably contributes as to which kind of evolution an organism will go through. If survival chances are low, selection would prefer those organisms with the ability to have offspring multiple times thus favoring Iteroparity. Migrating patterns probably also play a role in which type of evolution is present. In those organisms with long venutures and short life spans (for example monarch butterflies) Semelparity would probably be favored.

Gordie

5. What does a life history tell about an organism? Describe the environmental conditions in which K-selection and r-selection occurs.


 * Chapter 54 Community Ecology (Tom, Albert, Phil, Monika) **

Question 1: Using your newly acquired knowledge, what are the three symbiotic interactions? Give an example of each that distinguishes each interaction from each other.

Question 2: What is the difference between Batesian Mimicry and Müllerian Mimicry, and how does it benefit both predator and prey?

Question 3: A community appears to be organized by a top-down model, what bio- manipulation would be preferable to control excessive plant growth? (There are four trophic levels; plants, herbivores, primary predators, top predators.)

Question 4: Name three different ecosystem engineers (not real people), and how each is a “foundation specie” for their environment.

Question 5: Describe three different factors that help determine the equilibrium number of species in the island equilibrium model.


 * Chapter 55 Ecosystems Questions (Jacob, Kellen, Elena, Eli) **

1) What is the law of conservation of mass? How does it relate to ecosystems?

2) Describe the differences between primary and secondary producers, primary and secondary consumers.

3) What is the secondary production of an ecosystem compared to the primary production?

4) Go through the process of a biogeochemical cycle.

5) Explain the nitrogen and phosphorous cycle.

Chapter 37 Plant Nutrition (** Sabrina, Ella, Joann) **

1. Explain the significance of the interactions between earthworms and soil. How does the soil benefit from this relationship? The Earthworm? Earthworms, found as deep as eight feet beneath soil, bring basic minerals to the topsoil.These minerals provide elements which plants need for healthy growth. The worms aerate the soil through their burrowing, allowing oxygen to reach the roots of plants. Furthermore, through the “eating” of soil, earthworms deposit castings or droppings that help create more fertile soil.

2. What are some farming techniques implemented in attempt to improve soil conditions and prevent soil mismanagement? What new problems have been caused by these techniques? Several ways in which genetic engineering is improving plant nutrition and fertilizer usage include resistance to aluminum toxicity (caused from acidic soil, damages roots and greatly reduces crop yields), flood tolerance, and "smart plant," or plants that signal when a nutrient deficiency is imminent before damage has occurred.

3. Explain the role of one of the essential elements required by plants. What are some of the ways genetic engineering has been able to combat nutrient deficiencies? Plants require 8 micronutrients including iron, chlorine, copper, zinc, manganese, molybdenum, boron, and nickel. They also require macronutirents including carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, potassium, magnesium, and calcium. They require more macronutrients than micronutrients. Plants can be grown hydroponically to determine which mineral elements are essential nutrients. The solutions of minerals in which they are grown is called a concentration. -Ella 4. Describe the mutualistic relationship between plants and Rhizobacteria and explain the benefits received by each party. Rhizobacteria stimulates plant growth by producing chemicals to stimulate plant growth, by producing antibiotics to protect roots from diseases, or by absorbing toxic metals or make nutrients more available to roots. Rhizaobacteria benefits form the plant relationship because it needs the bacterial adaptations that the plant undergoes to obtain nutrients and thrive, just like a plant. -Ella 5. Compare and contrast ectomycorrhizae from arbuscular mycorrhizae (endomycorrhizae.) Ectomycorrhizae exists when mycelium forms a dense sheath over the surface of a root, increasing surface area. This causes the roots to be thicker, shorter, more branched, and have less root hair than other roots. Endomycorrhizae exists when fine fungal hyphae extend from root to soil. These roots resemble normal roots and are found in more than 85% of all plant species. This relationship occurs when microscopic soil hyphae respond to the presence of a root by growing toward it. -Ella