Section One—Terms

  1. Convergent evolution

    2. When organisms that are directly unrelated to each other and have analgous structures/features, converge on som common feature, e.g., streamling in fish and mammals, this is called convergent evolution. 

    2. Ecotype

    When a group of individuals belonging to a species are genetically adapted to a particular habitat, these individuals are desginated as an ecotype. 

  2. Ectotherm

An organism whose body temperature is maintained via external sources of energy (radiated heat from the ground, sun, etc.) rather than internal means (cellular metabolism).   
  1. Ecological niche

As defined by Hutchinson, a niche is the resultant n-dimensional hypervolume of all the conditions associated with the organism. It can be further divided into functional and realized niches.
  1. Aposematism

When an organism evolves to have a color pattern similar to that of another organism because the color pattern in that other organism tells predators not to bother it (either because it tastes bad or spines, etc.) 
  1. Resource

    2. As defined by Tilman, anything that is consumed by an organism is a resource for that organism. It get somewhat complicated by the fact that all things consumed are not totally useful to an organism. It differs from a condition which can be defined as features which affect the organisms survival, but are not consumed in the literal sense.

  2. Fecundity

    3. Fecundity is a measure of female reproductive success, i.e., the number of young that a female may have over the course of her life time.

  3. Iteroparity

    4. A reproductive strategy where the organism has many episodes of reproductive activity throughout its life time.

  4. Migration

A directed movement away from or towards a particular environment, usually by a group of individuals.

 

10.Dispersal

A non-directed movement away from a source location (specific environment) that results in avoidence of competition with adults, expansion of territory, movement to more suitable habitat, etc.

Section Two-Comparisons

    1. What are the advantages and disadvantages to outbreeding?

      2. Advantages--Results in hybrid vigor where individuals are more robust, healthier and more successful in survival rates than those of the orignal population. Also incorporates different genetic material in the genome which might be advantageous as environments change.

      Disadvantages--Disrupts the finely tuned genetic make-up of individuals of a species population. This genome has been selected for over a long period of time and is the most suitable for the particular conditions being experienced by the species population.

    2. How does a unitary organism differ from a modular organism?

      3. All functions are carried out by the parts of a unitary organisms, whereas in a modular organism there is a division of labor amongst the parts. The parts can almost be thought of as separate/distinct individuals, even though they are genetically identical. There is also associated a time constraint. A unitary organims is essentially "time-less" . It may change through time, but it remains as one object through time. In contrast a modular organism changes through time in terms of its constituent parts.

    3. How do desert and forest plants respond differently to light?

      4. Desert plants are subject to high light intensities with little to no shading. Thus they minimize leaves by putting chlorophyl into stems and stalks. They also use a photosynthetic method that does not max out with respect to changes in light intensity. In contrast, except for at the top of the canopy, forest plants are subject to very low light intensities. Thus they maximize leaf surface area, not only in individuals leaves, but also in layers of leaves. They also use a photosynthesis that is most suitable for low light intensities.

    4. How are the marsupials of Australia similar to the placentals of the rest of the world?

      5. The marsupials and placentals are related to each other phylogenetically and demonstrate parallel evolution. They have evolved to have similar morphologies and sizes, but not necessarily similar ecological functionalities. Thus we have both marsupials and placental mammals that are rodent-like, cat and dog-like, diggers, runners, etc.

    5. How do ectotherms compare to endotherms in terms of energy utilization?

Since ectotherms are dependent upon external sources of energy for body temperature maintenance, they can put more energy into reproductive matters. At the same time, activity cycles are closely tied to environmental patterns of temperature and they may be inactive for long periods of time. As endotherms use energy to produce body heat, less of the intake goes towards reproductive success and more towards maintenance of normal metabolic activities. Because body temp is not dependent upon external temperature patterns, the endoterms can be more continuously active. This also means extra energy costs, but at the same time some benefits accrue as they are able to prey on the less active ectotherms. 

Section Three—Lists

  1. List five of the propositions that compose Darwin’s theory of natural selection.

1. all species tend to produce more offspring than can be supported by the environment

2.offspring vary in their attributes, those with the "good" attributes survive, those lacking "good" attributes die.

3.The environment does the selection of survivors

4.Lines with good attributes are selected for, other lines goes extinct

5.Thus a species will change through time as its set of characteristics change through time.

2.List and briefly describe four conditions that affect organisms and their success in different environments.

a. temperature--temperature effects metabolic rates. A measure of this is called Q10 where with a ten degree change in temperature, we measure a doubling of a rate

b. precipitation--environments having low values are called deserts. For plants, moisture availability deals with evapotranspiration
    1. PH--has an effect on the way bio-catalysts work for organisms
    2. Wind--high wind environments require deep and extensive root systems, or a design of an organism to moderate the effects of wind.

3.List and briefly describe each of the three modes of photosynthesis.

    1. C3--typical for most forest plants and other plants growing in low light environments. High rates of evapotranspiration, lots of CO2 available because of high rates of decomposition in the soil. Leaves arranged in canopies. Photosynthesis inhibited by higher light levels because of molecular pathways.
    2. C4-typical for most grasses in grassland environments. High light intensity, problem of water loss compensated for by design of leaf and placement of stomates. Leaves arranged in vertical pattern. Photosynthetic rate does not change with light level.
    3. CAM-most cacti and other desert plants. Very high light levels, water availability a severe problem. Loss of leaves, location of chlorophyl in stems and trunks. Protection of fleshy material by spines. Actual production of photosynthate takes place at night to avoid problems of water loss

4.List and briefly describe three methods used to enumerate organisms in natural environment.

    1. mark-recapture--collect set of organisms, mark them in some fashion so that when recaptured, identity can be asscertained. Release them and allow them to mix and then collect another set of organisms. Determine relative percent composition of marked and un-marked individuals.
    2. Plots-set up a plot of known size and then count every single occurrence of habitation inside boundaries of plot
    3. Plot-less--Usually point quarter technique. Setup a series of points and then measure the closest occurrence of an organism in each quadrant surrounding the point.

5.List and briefly describe three kinds of migration patterns.

  1. One way trip, no return--when an organism leaves a location to travel to another location and dies at that location. Next generation returns to original location.
  2. Return trip, one occurrence--when an organism is born in one location, migrate to another for adulthood and returns to first for reproduction and then dies immediately after reproducing
  3. Return trip, more than one occurrence-when an organism is born in one location, migrates to another for adulthood and then returns to first for reproduction, but does this any number of times before death.

Section Four—Concepts

1.What is meant by the term "seed banks" and how is the strategy of a plant similar or different from that of an animal with respect to the concept of dormancy?

 The seed bank is the collection of seeds in the soild that did not germinate in the same year they fell to the ground. Both animals and plants have adopted this strategy as a way to disperse chronlogically. Annua; plants would more likely produce sees that are banked than perrenials, which can iether see or not seed in a particular year. The stages of an animal that undergoes dormancy may not be functionally equivalent of the seed stage (eg. Nymphal and

 

2.What are some of the functions of dispersal and why must all organisms disperse at some time during their existence as a species?

a. expansion of territory

b.movement to a more suitable environment

c.avoidance of competition (both intra and interspecific

No environment every remains perfectably stable. Therefore even though a particular location may be suitable at this time, if changes occur and the organism can not disperse, extinction result.

3.How does a generalist differ from a specialist? What are the advantages that accrue to each?

A generalist makes few demands for specific resources and as a result shows low efficiencies when one or more resources are vey abundant. A specialist shows very effective utilization of a resource when that resource is abundint in an environment that changes very little. It is very unsuccessful if the resource it depends upon disappears.

 

4.How do deep-sea vent communities differ from grasslands in terms of the energy source that funds the environment? In terms of energy flow through the environment?

Vent communities are funded by chemosynthetic bacteria tha are able to use metallic substances (Fe, Ni, HsS, etc). Grasslands are totally dependent upon photosynthetically derived energy. Energy flow in vent communities is very different because the chemosynthesizers are most often symbionts and the excess energy they produce is immediately available. In grasslands, there are few symbiotic relationships and much of the productivity is not consumed or used immediately. It therefore falls to the ground and contributes to the organic matter in the soil layer.

5.What is meant by the term "life form"?

 A life form is the particular morphology evoled by a species that is adaptive to the environment inhabited. One example would be Raunkiaers classification of plants based on the location of the apical meristem tissue. Another woulbe be the body forms of mammals associated with the various guilds (burrowers, saltators, etc.).

Section Five—Thought questions

1.Global warming is an established feature of our present environment. Discuss some of the affects global warming might have in the context of the material covered in the first five chapters. (use this side of the paper for this answer)

a. conditions--high temperatures rather than low temperatures might be more stressful. Changes in patterns of precipitation along with temperature will be important.
  1. Resources-same resouces will be present, but will be redistributed thus requiring either dispersion or new adaptations. For example, at the end of the Pleistocene, NH was still covered by tundra and it took a while for forest trees to migrate here.
  2. Life history strategies--dormancy may become a less important as a method of lasting through periods of cold because the cold periods may not last as long.
  3. Dispersal/migrations--As warming takes place, organisms lacking means of dispersal may not be able to move to more suitable locations. Expansion of climate belts may shorten migratory routes (eg. Organisms with a tropic to arctive routes won’t have as far to go). Expansions of climate belts may disrupt existing migratory routes (eg., disappearance of marshes along flight paths)
  1. The human species can not be apart from the natural world, but is a part of the natural world. Discuss the implications of this statement in the context of the material covered in the first five chapters. (Use the reserve side of this page for your answer).

a. Conditions-We are a generalist species, a weed species. Therefore we have had good success in almost every environment we have come to inhabit. We compensated for adverse conditions by technology rather than evolutionary change.
    1. Resources--Our lives are lived with energy subsidies that are not maintainable. We use resources in a nonsustainable manner. We can transform resources from one state to another (eg., use of corn for auto fuel) even though the end product of that transformation may be very costly in terms of production.
    2. Life history strategies--Our population growth shows that we are r strategists rather than k strategists. This is true even though we are large bodied and long lived. Thus we don't seem to show density dependencies in birth rates associated with population growth. Perhaps this is related to the way in which we utilize resources

c. Dispersonal/migration--We have already dispersed to all suitable parts of the globe. Dispersal to other planets at this time is not a viable option. Political geography prevents for the most part migratory pattern that earlier humans might have used (eg., gypsys in southern Europe, buffalo hunters on the North American plains)