An Introduction to Ecology

1

• An Introduction to Ecology
• Distribution and Adaptations of Organisms

2
Ecology

• (from the Greek oikos, home and
• logos, to study)
• the scientific study of the interaction between
  organisms and their environments
• ecology incorporates hypothetico-deductive
  methods, using observations and experiments to
  test hypothetical explanations of ecological
  phenomena

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Ecology

• Math
• Genetics
• Geology
• Biology
• Chemistry
• Physics

4
Ecology

• behavioral biology -entomology
• physiology -land-use planning
• public health - molecular biology
• agriculture - agronomy
• computer science - engineering
• forestry - oceanography
• evolution
• bacteriology

5
Environment

• all external conditions and factors, living and
  nonliving that affect an organism or other
  specified system during its lifetime
• abiotic (temperature, light, water, nutrients,
  etc.)
• biotic - organisms that are part of any
  individuals environment

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Ecology

• autecology - concern with individual species
• synecology - concerned with the group
• kinds of ecology
• aquatic -island
• marine -paleoecology
• freshwater - behavioral
• desert - applied
• forest - exotic

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• subatomic particles ---gtatoms ---gt molecules
  ---gtprotoplasm ---gt cells ---gt tissues ---gt
  organs ---gt populations ---gt communities ---gt
  ecosystems ---gt biosphere ---gt planets ---gt solar
  systems ---gt galaxies ---gt universe

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• bioshpere - largest, most nearly self sufficient
  biological system
• biome - large regional or subcontinental
  biosystem characterized by major vegetation
  type or other features
• ecosystem - community nonliving environment
• community - all populations in a given area
• population - groups of individuals of any one kind

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Ecosystem

• 1877 - Karl Mobius (Ger.) biocenosis used in
  description of organisms along an oyster reef
• 1887 - S. A. Forbes (U.S.) microcosm used in
  relation to a lake
• 1935 - A. G. Tansley (G.B.) coined Ecosystem
• 1940s - V.V. Dokuchaev (USSR) and G. F. Morozov
  (USSR) emphasized biocenosis
• 1940s geobiocenosis expanded from biocenosis

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Abiotic Factors

• light
• soild
• currents and pressures
• nutrients
• atmospheric gases
• water
• temperature
• environmental effects, i.e. fire, flood, drought

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Light

• different responses to different wavelengths
• photosynthesis (red and blue most efficient)
• red algae (absorb green to aid in photosynthesis
  because water absorbs blue light)
• color vision (fish, some reptiles, birds, most
  mammals)
• cockroaches and other insects (uv)

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• photoperiodism - response to duration of light
• latitude of 40N (Washington, DC) has day length
  range of 6 hours in winter to 18 hours in summer
• affects daily, seasonal, annual balance
• migration of birds (buzzards, swallows)
• shedding of leaves in the fall
• color changes in fur
• blooming of flowers
• long day (bloom in summer)
• short day (bloom in spring and fall)

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• intensity
• rate of photosynthesis
• singing of birds
• order in which birds sing
• strength of song

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Water

• Precipitation
• hydrologic cycle 97-99 of water transpired each
  day
• succulents - 500 g water 1 g glucose
• Humidity
• absolute (amount of water in air)
• relative ( of water in air compared to how much
  air can hold at same temperature and pressure)
• Aquatic environments
• marine
• freshwater

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Hydrologic Cycle

• transpiration
• precipitation
• condensation
• evaporation
• percolation
• runoff
• ground water

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Temperature

• plants and temperature
• extremes in temperatures (more perennials)
• affects transpiration
• modifications to retard or speed up transpiration
• animals (thermoregulation)
• most plants and animals are poikilotheremic
  (cannot maintain a constant temperature - not
  cold blooded)

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• diapause (resting stage, i.e. insects during
  temperature extremes)
• estivation (summer dormancy, i.e. frogs burrowing
  into mud during hot periods)
• homeothermic (body temperature regulated
  internally and remains fairly constant)
• turpor (suspended animation, i.e. bears body temp
  drops during cold weather to conserve energy
• hibernation (severe reduction in body temperature
  for prolonged periods (ground squirrels, bats,
  ground hogs, whip-or-wills)

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Thermoregulation

• behavioral
• turpor
• hibernation
• estivation
• anatomical
• ears of rabit and elephant dissipate heat
• body hair
• physiological
• rete mirabile
• capillaries
• temperature

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Atmosphere

• trophosphere 0-17 km
• 78 nitrogen
• 21 oxygen
• lt1 Ar
• 0.035 carbon dioxide
• 0.01-5 water vapor
• stratosphere 17-48 km
• ozone layer 17-26 km
• mesosphere 48-94 km

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Pollutants in the Atmosphere

• carbon oxides
• carbon monoxide (CO)
• carbon dioxide (CO2)
• sulfur oxides
• sulfur dioxide (SO2)
• sulfur trioxide (SO3)

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• nitrogen oxides
• nitric oxide (NO)
• nitrogen dioxide (NO2)
• nitrous oxide (N2O)
• volatile organic molecules
• methane
• benzene
• chlorofluorocarbons
• bromine containing halons

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• suspended particulates
• dust
• soot
• asbestos
• lead
• arsenic
• cadmium
• nitrates (NO3-)
• sulfates (SO4-2)

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• droplets (liquids)
• sulfuric acid (H2SO4)
• oil
• polychlorinated biphenyls (PCBs)
• dioxins
• pesticides
• photochemical oxidants
• ozone (O3)
• peroxyacyl nitrates (PANs)
• hydrogen peroxide (H2O2)
• aldehydes (formaldehyde)

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• radioactive substances
• Radon 222
• iodine 131
• strontium 90
• plutonium 239
• heat
• noise

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Currents and Pressures

• Wind
• Krummholz structure on vegetation (gnarled,
  twisted, supine trees at tree-line)
• flagging structure on vegetation
• Water currents
• structural adaptations of plants animals
• behavioral adaptations (rheotaxis)
• Air Water Pressure (33 feet, 1 atm)
• Gravity
• geotrophisms

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Global Air Circulation and Rain Shadows to Form
Deserts
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Environmental Affects

• Fires
• fire ecology
• slash, longleaf habitats
• jack pines, sand pines
• everglades
• grasslands
• pitcher plant bogs
• scrub oaks
• animals (scrub jays)

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• Floods
• Drought
• Tolerances in Plants
• surface area of leaves
• pubescence of leaves
• hypodermis in pines
• wax coatings
• extra layers of epidermis
• sunken stomata
• Tolerances in Animals
• uric acid and urine concentration
• behavioral patterns

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Nutrients

• How do organisms obtain nutrients?
• photosynthesis
• food webs, food chains
• cycles
• carbon
• phosphorus
• nitrogen
• water
• oxygen
• sulfur

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Leibigs Law of the Minimum

• All organisms need minimum amounts of nutrients
  in order to survive, grow, and reproduce.
• Also includes heat, light, water, etc.

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Nutrients

• Macronutrients
• nitrogen
• potassium
• calcium
• phosphorus
• magnesisum
• sulfur

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• Micronutrients
• iron
• chlorine
• copper
• manganese
• zinc
• molybdenum
• boron
• Elements Essential to Some Plants or Animals
• sodium
• cobalt

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Soil Profile

• humus (organic matter)
• topsoil (decomposing organic material, live
  organisms, some minerals)
• zone of leaching
• zone of accumulation (iron, aluminum, organic
  matter, clays)
• parent material (partially broken down inorganic
  material)
• bedrock (impenetrable for most part)

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Formation of Soil From Rock

• Mechanical Weathering
• frost action
• frost wedging
• frost heaving
• abrasion
• pressure release
• plant growth (roots)
• burrowing animals
• crystalizations of salts
• temperature extremes, i.e. forest fires

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• Chemical Weathering
• oxygen 4FE 3O2 ---gt 2Fe2O3 (hematite)
• acids
• CO2 H2O ltgt H2CO3 ltgt H HCO3-
• (carbonic acid) (bicarbonate ion)
• CaCO3 CO2 H2O ltgt Ca3 2HCO3-
• (calcite)
• or
• CaCO3 H HCO3- ltgt Ca2 2HCO3-
• solution weathering (see above)
• lichens

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Soil and Climate

• due to climate, water movement affects soils
• pedalfers (eastern U.S.) effective downward
  leaching due to high rainfall acids produced by
  decaying humus. (high aluminum and iron oxides)
  - clay, minerals
• pedocals (western U.S.) little leaching-
  evaporation pulls water out of ground
  (precipitation of salts, especially calcite)
  alkalai soils, heavy sodium salts
• laterites (tropical) high rainfall, heavy
  leaching - red soils with iron and aluminum
  oxides (nonproductive soils because of excess
  leaching)

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Alexander Von Humboldt(1769-1859)

• German scientific explorer
• extensive exploration in Mexico, down through
  Ecuador
• realized species diversity of tropical rain
  forests
• recognized plants occur in repeatable groups
  relating to soils, climate, and biological
  interactions
• relationships between plant communities and
  latitude and altitude
• influenced Thomas Jeffersons exploration of
  Louisiana Purchase
• Humboldt Current named after him

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Altitude, Latitude and Plant Communities

• snow
• tundra
• taiga (boreal forests) tall trees with spiphytic
  mosses, liverworts and lichens
• temperate forest
• tropical rain forest

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Biotic Factors

• symbioses
• mutualism
• commensalism
• parasitism
• predation
• competition

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Competitive Exclusion Principle

• No two species can coexist indefinitely on the
  same resource.
• Methods to avoid competition
• live in separate areas (geographic separation)
• live in different habitats within same
  geographical area
• use same habitat differently (i.e. vertical or
  horizontal separation)
• temporal separation
• nocturnal
• diurnal
• reproductive cycles

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Law of Tolerance

• abudnance of organisms is greatest with tolerance
  to the environment. (There is not only a minimum
  but a maximum to environmental parameters

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Gaia Hypothesis(Gaia Gk. earth goddess)

• developed by James Lovelock in conjunction with
  Lynn Margulis
• states life (especially micro-organisms) have
  evolved with abiotic factors to produce a
  controlled system that maintains earths
  favorable condition for life
• life maintains the physical environment which in
  turn maintains the biotic environment

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Terrestrial Biomes

• tropical forests
• savannahs
• deserts
• chaparral
• temperate grasslands
• temperate deciduous forests
• taiga
• tundra

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Freshwater Biomes

• ponds and lakes
• streams and rivers

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Marine Biomes

• estuaries
• intertidal zones
• coral reefs
• oceanic pelagic
• benthos

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Homeostasis and the Principle of Allocation

• homeostasis - the maintenance of a steady-state
  internal environment in the face of extremes in
  external environment
• regulators
• conformers
• principle of allocation - each organisms has a
  limited amount of energy that can be allocated
  for obtaining nutrients, escaping from predators,
  coping with the environmental fluctuations,
  growth and reproduction