final (5,7,8)

chapter 5 - biodiversity

  • a population is a group of individuals of the same species living in the same area

  • a species is all individuals capable of interbreeding

  • 9 reasons why people value biodiversity (UPEMTARSC):

    • utilitartian

      • certain species provide a product that is of direct value to people (milk, meat, etc)

    • public-service

      • nature and diversity providing a service that is useful/essential to human life (taking in co2, pollinating flowers, etc)

    • ecological

      • when species have certain roles in their ecosystems

    • moral

      • the belief that species have a right to exist independent of their value to humans

    • theological

      • the belief that some religions value nature and its diversity

    • aesthetic

    • recreational

    • spiritual

    • creative

  • 3 concepts of biodiversity:

    • genetic diversity

      • total number of genetic characteristics of a species

    • habitat diversity

      • different kinds of habitats in a given unit area

    • species diversity

  • approx 2.2 million named species exist on earth today, but estimates suggest 8.7 million

  • 3 ways species interact:

    • competition

      • negative outcome for both

    • symbiosis

      • positive outcome for both

    • predation-parasitism

      • positive for one, negative for the other

  • competition exclusion principle (4C):

    • states that two species with the exact same requirements cannot coexist in the exact same habitat (complete competitors cannot coexist) - one will always go extinct

  • how can 2 million species exist if the 4C principle exists? the ecological niche!

  • the ecological niche is the role played by the species in a community. a niche describes how a species obtains food, its relationships with other species, and the services it provides its community

    • niche = job

    • in a mixed environment they can coexist by dividing up the habitat

  • if we want to conserve a species in its natural environment, we must make sure that all the requirements of its niche are present

    • when we conserve a population we also conserve its habitat and niche

  • a partner in symbiosis is called a symbiont

  • 3 types of symbiosis

    • commensalism

      • one benefits, one is unaffected

    • mutualism

      • both benefit

    • obligate

      • neither can survive without one another

  • lichens: combo of algae and fungi in mutualistic symbiosis

  • a predator feeds on prey, a parasite lives in / on host & gets food at the expense of the host

  • in a predator-prey relationship, the prey might actually benefit by eliminating unfit / nonadaptive genes from the gene pool (natural selection)

  • when organisms compete, what do they compete for?

    • energy and matter in useable forms

    • space

    • sites for life activities

  • the more similar the competing species, the more intense the competition

  • greater diversity occurs at lower latitudes

    • tropical regions near the equator have more stable conditions

  • type of land (type of soil, topography, slope, aspect, elevation, nearness to drainage basin, etc) influences the plants that grow in the habitat, in turn influencing the types of animals that grow

  • biome: a type of ecosystem (forest, desert, grassland)

  • keystone species:

    • species whose impact is larger than expected due to its low biomass



chapter 6 - pollution & toxicology

  • a polluted environment is one that is impure / dirty / unclean

  • pollution refers to an unwanted change in the environment caused by introducing harmful materials / producing harmful conditions

  • contamination is making something unfit for use through the introduction of undesirable material (like contaminating water)

  • toxin is a substance that is poisonous to people / living things

  • toxicology is the science that studies potentially toxic chemicals

  • carcinogen is a toxin that increases the risk of cancer

  • synergism:

    • the interaction of different substances resulting in a combined effect greater than the separate effects of the substances

    • synergism is not inherently good - like for example if u have toxin 1 and toxin 2 and u combine them u could get a harmful effect worse than their effects separately

  • pollutants are introduced into the environment by:

    • point sources

      • comes from a single, specific, measurable place

      • like pipes, spills, smokestacks

    • area sources / non-point sources

      • comes from many diffuse and scattered sources across a large area

      • like automobile exhaust, agricultural runoff

      • difficult to isolate and correct

  • 7 categories of pollutants (ITOTPEN):

    • infectious agents

      • infectious diseases spread by any living organism, people included

    • toxic heavy metals

      • heavy metals can accumulate in fatty tissue

      • Hg, Pb, Cd, Ni, Au, Pt, Ag, etc

        • eg sources of mercury: volcanic eruptions, burning coal, processing metals, incinerating waste. mercury in oceans can be found due to deposition from the atmosphere through precipitation

      • found in soil / water !!! not people !!!

      • by products of mining and using other elements

    • organic compounds

      • persistent organic pollutants (POPs)

    • thermal pollution

      • heat pollution

      • can be long and short term

    • particulates

      • small dust particles, like soot and asbestos

    • electromagnetic fields

      • like from phones

    • noise

      • unwanted sound energy

  • biomagnification / bioaccumulation is the accumulation or increase in the concentration of a substance in living tissue as it moves through a food web

  • methylation is the changing of inorganic mercury to methyl mercury through bacterial activity

    • bacterial activity leads to methylation

    • methyl mercury is more toxic than inorganic mercury


chapter 7 - water & environment

  • freshwater sources: groundwater & surface water

    • groundwater

      • water table is the upper surface of groundwater

      • an aquifer is an underground layer of rock, sand, or gravel containing usable significant amounts of groundwater. it has high porosity and permeability

        • confined aquifer is an aquifer below the land surface that is saturated with water

          • between two lands

        • unconfined aquifer is a body of water formed from groundwater, rain water runoff, etc

          • no land layer above it

    • surface water

      • like streams, rivers, lakes

  • desalination is turning seawater into freshwater

    • desalinated water has a place value - the price rises depending on how far water must move from plant

  • how to determine water quality?

    • how clear it is (turbidity)

    • smell, taste

    • pH (7 +- 1.5)

    • < 1000 ppm

  • BOD - biochemical oxygen demand

    • when BOD is high, the dissolved oxygen content of the water may become too low to support life

  • dissolved oxygen content must be higher than 5 mg /L

  • P and N cause water pollution problems

  • eutrophication

    • when a body of water develops a high concentration of nutrients, increasing growth of aquatic plants, bacteria, and algae