Conservation biology-multidisciplinary science created to deal with the crisis of maintaining the genes, species, communities, and ecosystems that make up earth’s biological diversity. Uneven-aged management-method of forest management in which trees of different species in a given stand are maintained at many ages and sizes to permit continuous natural regeneration. Even-aged management-method of forest management in which trees are maintained at about the same age and size and harvested all at once Intrinsic/Existence value- value of an organism, species, ecosystem, or the earth’s biodiversity based on its existence regardless of whether it has any usefulness to us
Instrumental value-value of an organism, species, ecosystem, or the earth’s biodiversity based on its usefulness to us Old-growth forest-containing trees that are often hundreds, sometimes thousands years old Second-growth forest-stands of trees resulting from secondary ecological succession Tree plantation/tree farm-site planted with one or only a few trees in an even- aged stand Deforestation-removal of trees from a forested area without adequate replanting Ecological restoration-deliberate alteration of a degraded habitat to restore as much of its ecological structure and function as possible
Old-growth tress are found in the western portion of the US and in Russia, Brazil, Canada, Indonesia 63% of the world’s forests are secondary-growth Clear-cutting increases sediment pollution and soil erosion
Large reserves sustain more species and provide greater habitat diversity than do small reserves. The size of the population determines the amount of activity taking place that will ultimately impact the environment, usually in a negative way. Urbanization is the biggest cause for the destruction of arable land and areas with a lot of biodiversity.
Even-aged management is demonstrated in the figure below because it shows a fast growing and economically desirable species being harvested. Uneven-aged management focuses more on biodiversity of a species, whereas even-aged is more about monoculture.
•Soils vary due to diff. : Climate Parent Material Geography Age And the presence of soil organisms•It is composed of: Weathered rock Partially decomposed organic material And organisms
Particlesof SoilVary in size fromlarge to smallorder:1)Sand2)Silt3)Clay
Soil horizons: the layers of soil formed O Horizon=> composed of partially decomposed organic material & /or leaf litter. A Horizon=> beneath the O Horizon; Known as topsoil composed of mineral Containing weathered parent material & organic matter (humus) Plants spread most of their roots to absorb water and minerals B Horizon=> Known as subsoil; contains a lower concentration of organic material than he first two layers & a higher concentration of mineral particles. C Horizon=> Composed of Weather parent material sitting on top of bedrock.
Feeding a Growing Population Malnutrition: A lack of sufficient protein, carbohydrates, fats, vitamins, or minerals. Undernutrition: A problem most occurring with developing country pop., lack of nutrition Overnutrition: A problem that leads to obesity, most associated with developed countries.
Industrialized Agriculture: Provides most of the world’s food by using heavy, fossil fuels, irrigation water, inorganic chemical fertilizer, & pesticides to farm high yielding monocultures. Plantation Agriculture: Used in developed countries to grow cash crops like: Coffee Sugar Cane Bananas Cacao Subsistence Agriculture: The practice of farming to provide for one’s family food needs with enough remaining to sell or trade for additional necessities. Slash-and-Burn Agriculture: The practice of cutting down and burning tropical forests to clear the land for planting crops, raising livestock.
Soil Erosion: after plowing and/or harvesting the soil that is exposed to the elements is susceptible to being blown away by winds or washed away by water. Caused by: Excessive irrigation (as crops are being grown even if the land is not exposed) Soil conservation strategies: No-till agriculture: refers to farming without plowing the land, this avoids exposing the soil to direct sun, wind, or water. Terracing: Involves converting a hilly slope to flat terraces that follow the contours of the slope. This makes it possible to farm heavily sloped hillside, and is common in many rice-growing areas in Asia. Counter Plowing: The practice of plowing across the slope of a hill rather than up and down a slope. Reduces erosion by preventing runoffs and water from gaining momentum as it flows unimpeded down a slope. Windbreaks: Rows of shrubs or trees that are planted next to or around fields to slow down the winds that could blow topsoil off of the land. Deforestation: Results from clearing land for agriculture. The removal of trees destroys habitats for plants, & animals that live within or feed off of the particular tree
Rachel Carson published a book Chemicals such as the following named the “Silent Springs" in have been developed to kill or 1962; raised public awareness control pest pop.: about the environmental Herbicides(used to control consequences of DDT use and weeds) played a crucial role of raising Fungicides (used to control environmental issues in the U.S. fungus) Rodenticides (used to control rodents, mostly rats and mice) Intesticides(Used to control Insects) DDT: (Dichlorodiphenyltrichloroethane) a synthetic organic compound introduced in the 1940s and used as an insecticide. Tends to persist in the environment and become concentrated in animals at the head of the food chain. Its use is now banned in many countries.
It is unlikely that every member of a pop. Of creatures will die off in effect to the pesticides; therefore a resistance will form and that will be transferred to the offspring of the survivors. After some time, a new pesticide will need to be created to keep up. (IPM) Integrated Pest Management: is an approach which first assesses the pest situation, evaluates the merits of pest management options and then implements a system of complementary management actions within a defined area. The goal of this is to reduce the number of pests to economically tolerable levels.
1. The largest area of old-growth forest in the United States is located in: a) Alaska b) Montana c) California d) North Carolina e) Michigan2. Which of the following is most likely to occur in a forested region that has been recently clear-cut? a) The average depth of topsoil will increase b) The water temperature in streams running through the region will decrease c) Volume of runoff after rain will decrease d) The concentration of nitrates in streams running through the region will increase e) The frequency of landslides will decrease3. Fragmenting one large park or preserve into many small parks with human habitation in between them is most likely to lead to which of the following? a) Stabilization of microclimates b) Decrease in the proportion of edge habitat c) Reduction of species diversity d) Increase in gene flow within species e) Increase in population size of top carnivores4. Road construction, logging, and mining are banned in which of the following federal lands? a) National parks b) National wildlife refuges c) National forests d) National wilderness preservation areas e) National resource lands5)Which of the following would most likely have the greatest positive impact in the quality of the natural environment worldwide? a) Discovery of new reserves of fossil fuels in coastal areas b) Increased agricultural production on marginal desert land c) Increased life expectancy in more developed nations d) Increased reliance on food from ocean ecosystems e) Stabilization or reduction of the size of the human population
6) Which of the following best explains how a pest develops resistance to a chemical pesticide? a) Natural selection takes place b) The pest develops adaptations during times of secondary pest outbreaks c) Mutation and genetic drift occur d) Geographic isolation results in the emergence of new pest e) Punctuated equilibrium7) Which of the following problems can be addressed with counter plowing? a) The failure of terracing b) The exercise use of pesticides c) Soil erosions d) Waterlogging e) Soil salinzation8) Which of the following is a feature of integrated pest management? a) It makes use of the natural enemies of pests b) It makes effective use of disease transfer organisms c) It relies on the use of intermittent groundwater pumping stations d) It requires intense cultivation of marginal land e) It is most effective on land within 100 miles of the coast9) This layer of soil is also known as the topsoil; it contains much humus a) A Horizon b) B Horizon c) C Horizon d) O Horizon e) Z Horizon10) The connection between farming and ecological succession is best exemplified by which of the following? a) Farmland is maintained permanently in a state of late succession b) Farmland is maintained permanently in a state of mid succession c) Farmland is maintained permanently in a state of primary succession d) Farmland is maintained permanently in a state of early succession e) Farmland artificially skips the first stage of succession