An Introduction to Ecology

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An Introduction to Ecology

• The Distribution and Adaptations of Organisms

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Introduction to Ecology

• Ecology is the study of organisms and their
  interactions with their environment.
• The environment includes 2 types of factors
• Biotic factors the living parts of the
  environment
• Plants, animals, bacteria, fungi, protists
• Abiotic factors the nonliving parts of the
  environment
• Water, oxygen, light, temperature, etc.

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Abiotic or Biotic?
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Abiotic or Biotic?
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Abiotic or Biotic?
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Abiotic or Biotic?
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Levels of Organization

• Ecologists can look at the world in levels of
  increasing complexity
• Population
• A group of organisms of the same species that
  live together in a certain area
• Example a pride of lions in the Serengeti
• Community
• A group of organisms of different species that
  live together in a certain area
• Example all of the organisms living in or around
  a lake
• Ecosystem
• All the living and nonliving things in a certain
  area
• Example Lake, trail in Red Rock Canyon
• Biome a group of ecosystems that have similar
  climates and communities
• Example Tundra, Desert, Deciduous Forest
• Biosphere the entire portion of the planet that
  supports life

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Distribution of Species

• When considering ecology, the distribution of
  species are determinant in how an ecosystem
  evolves
• Dispersal is the movement of individuals away
  from centers of high population density or from
  an area of origin
• Biological imperative is to breed and pass on
  genetic information (thus they should spread)

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Strategies for Dispersal

• Many species are not able to migrate to all parts
  of the world (geographic barriers)
• Some organisms can overcome these barriers and
  allow species to spread
• One method is known as natural range expansion
  (the organism is able to overcome barriers and
  begin colonies in different locations)
• Example many species of strong flying birds
  (egret, grackle) have expanded into Africa,
  Eurasia, Australia and recently (last 150 years)
  both of the Americas

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Strategies for Dispersal

• Another method to move species to new areas is
  Species Transplants
• Humans love to influence their natural
  surroundings
• We have brought many foreign species into new
  habitats
• Example Mammals are slowly taking over many of
  the niches in Australia
• The Eucalyptus tree in Australia has several
  footholds in California

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Success of Dispersion Biotic Factors

• Even though an organism is able to spread to a
  new environment, it does not mean that it will be
  successful
• Behavior of the organism may not be suitable to
  the environment (mating rituals, reproductive
  barriers, etc)
• Negative interactions with other organisms
  (parasites, predation, disease, competition for
  resources)

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The Importance of Abiotic Factors

• Not every organism can live everywhere on Earth
• Abiotic factors determine which organisms can
  survive where
• Temperature effect on body temperature
• Water too much/not enough water
• Light availability for photosynthetic organisms
• Wind amplifies effects of temperature
• Rocks/Soil which organisms can live with/on
  them, based on pH and mineral composition
• Periodic Disturbances catastrophes, such as
  tornadoes, fires, tsunamis, etc.

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Climate Abiotic Factor

• Climate combines four abiotic factors
  (temperature, water, sunlight, and wind)to
  determine prevailing weather conditions that
  greatly affect ecosystems
• Macroclimate patterns on a global, regional or
  local level
• Microclimate very fine patterns that are
  localized to very specific regions in an
  ecosystem (example communities underneath a
  log)

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Determination of Climate

• Many factors affect a global or regional climate
• Solar energy
• Planets movement in space
• Suns warming effect on the atmosphere
• Land
• Water
• Cycles of air movement
• Evaporation/Precipitation

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Oceans/Bodies of water

• Ocean currents have a huge influence on climate
• Heat or cool air masses (affects weather)
• In general, large bodies of water (lakes
  included) moderate temperatures
• Remember properties of water

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Mountains

• Mountains affect both amount of sunlight and
  rainfall
• Depending on which side of a mountain an
  ecosystem is on, they may receive more sunlight
  or less sunlight (if in the shade)
• Additionally, mountains force clouds to release
  their moisture before crossing over the peak
• One side of a mountain often receives
  significantly more precipitation than the other
• Elevation can cause different climates due to
  temperature, O2 content and precipitation

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Seasonality

• The Earths relative position around the sun
  determines the seasons
• Facing away from sun (fall and winter)
• Facing towards the sun (spring and summer)
• The different levels of solar radiation lead to
  variations in wind patterns, temperatures,
  variations in ocean currents
• All of these variations change the climate in a
  region that an organism must adapt to

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Microclimates

• As varied as macroclimates can be, microclimates
  have infinite variations
• Shading from biotic or abiotic structures affect
  sun exposure
• Clearing vs. forested can have effects on
  temperature and wind exposure
• High ground vs. low ground for water availability
• Above vs. below ground
• Again organisms must adapt to survive in each
  scenario

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Long-term Climate Change

• Even with the variety of change in climates,
  global climates (as a whole) are fairly
  predictable based on environmental data and
  historical analysis (otherwise, weathermen
  wouldnt have a job)
• Yet even large-scale climates can be altered over
  time
• Ice ages (last for about 40,000 100,000 years)
• Next ice age is predicted in the next 10,000
  years
• Global warming

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Long-term Climate Change

• Many of these changes will have far-reaching
  effects on ecosystems and species distribution
• Many of the extinctions that have taken place on
  Earth are due to an organisms inability to adapt
  to a changing environment

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Homeostasis

• Organisms must maintain homeostasis, a
  steady-state internal environment, despite
  changes in the external environment
• Organisms respond to abiotic factors in one of
  two ways (REVIEW)
• 1. Regulators (endotherms) maintain a nearly
  constant internal environment, despite external
  conditions (Warm-blooded)
• 2. Conformers (ectotherms) allow their internal
  environment to vary (Cold-blooded)
• - live in environments which remain relatively
  stable

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The Principle of Allocation

• This principle states
• Each organism has a limited amount of energy that
  can be spent on obtaining food, escaping from
  predators, coping with environmental fluctuations
  (maintaining homeostasis), growth, and
  reproduction

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Adapting to Changing Conditions

• Organisms can respond to their changing
  environments using 3 different types of
  responses
• 1. Physiological Responses
• - changing the functioning of the body
• - acclimation
• - athletes in Torino, moving to Denver...
• 2. Morphological Responses
• - changing the anatomy (structure) of the body
• - example dogs growing thicker fur

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Adapting to Changing Conditions

• 3. Behavioral Responses
• - changing behavior to adapt to the change
• - moving to a more favorable location
• - cooperative behavior (huddling, etc.)

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Overview of Biomes

• Not on AP test, but will be on MY test (good
  background information)
• Aquatic
• Terrestrial (Our focus will be on these!)
• Tundra
• Taiga
• Tropical Forest
• Savanna
• Chaparral
• Desert
• Temperate Grassland
• Temperate Deciduous Forest

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Tundra

• Arctic 20-60 cm/yr.
• Alpine (mountains) may exceed 100 cm
• Average winter temp. -30 degrees C
• Summer lt 10 degrees C
• Long winter short summer
• Herbaceous (low) plants, a few DWARF shrubs due
  to PERMAFROST.
• Musk oxen, caribou, reindeer, bears, wolves,
  various birds
• High latitudes or highest elevations (even at
  equator!)

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Taiga (Northern Coniferous Forest)

• 30-70 cm some much more
• Winters -50 degrees C in winter
• Summer 20 degrees C
• Long winter short summer may be hot
• Plants cone-bearing trees, diverse shrubs,herbs
• Animals Birds, moose, bears, Siberian tigers
  insects
• Northern N. Am. and Eurasia to edge of tundra

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Tropical Forest

• T. Rainforest 200-400 cm/yr
• T. Dry forest 150 200 cm/yr
• 25-29 degrees year round (Warm!)
• Summer year round
• Plants diverse 4 or more layers
• Animals diverse 5-30 million species yet to be
  discovered!
• Equatorial regions

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Savanna

• Seasonal rainfall 30-50 cm/yr with long drought
  season
• Temperature 24-29 degrees C (warm!) more
  variation that Tropical forests
• Dry season lasts 8-9 months
• Plants Scattered trees thorny small leaves
  (why?)Grasses Must be fire drought tolerant
• Animals Herbivorous mammals insects grazers
• Equatorial subequatorial regions

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Chaparral

• Seasonal ppt. Rainy winter Long dry summer
  (30-50 cm)
• Cool fall, winter, spring (10-12 degrees C)
• Summer can reach 30-40 degrees C
• Plants shrubs, small trees, grasses adapted to
  drought some have seeds that germinate after
  fire.
• Animals mammals (browsers) amphibians, reptiles,
  insects
• Mid latitude coasts

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Desert

• lt 30 cm / yr (arid/dry)
• Hot deserts gt 50 degrees C
• Cold deserts (Antarctica) lt-30 degrees C
• Temps vary seasonally and daily (colder at night)
• Plants Cacti, shrubs w/ deep roots (why?) small
  leaf surface area (why?)
• Animals lizards, scorpions birds insects many
  nocturnal animals (why?)

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Temperate Grassland

• Dry winters wet summers 30-100 cm/yr.
  seasonal drought
• Cold winters lt -10 degrees C Hot summers 30
  degrees C
• Plants Grasses
• Animals Large grazers burrowing mammals
• Plains prairies around the world

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Temperate Deciduous Forest

• 70-100 cm/yr
• Cold Winters 0 degrees Hot summers 35 degrees C
  4 distinct seasons
• Plants Trees, shrubs, herbaceous layer
  (broadleaved, deciduous plants)
• Animals variety of mammals, birds, insects
• Midlatitudes
• Our biome!