INTRODUCTION TO ECOLOGY

I. ECOLOGY: The Study of the interactions between organisms and the living and non- living components of their environment:

A.TODAY’S ECOLOGY ISSUES

  1. Named as a field of study in 1866
  2. Vast changes have occurred: 10-20, 000 years ago, our ancestors gathered and hunted….Survival depended on practical knowledge of the Environment
  3. Exploding Human Population **
  4. Population in 1930 2 Billion
  5. Population in 2000 6 Billion
  6. Increase in human population requires an increase in: Energy sources, food, and space for the disposal of waste.
  7. Sixth Mass Extinction (HOLOCENE PERIOD)
  8. The Thinning Ozone Layer
  9. Climatic Changes

B.LEVELS OF ORGANIZATION

  1. The Biosphere--- The part of the Earth that supports Life
  2. Ecosystem: Biome--- A unit of the biosphere, that includes all organisms and the nonliving environment living in a particular place.
  3. Community---All of the organisms in a given ecosystem
  4. Population---All of the members of a particular species living in a community at one time
  5. Organism---One species
  1. A KEY THEME IN ECOLOGY
  2. No Organism is isolated
  3. Interconnectedness
  4. All organisms interact with others in their environment
  5. All organisms interact with non-living components as well
  6. Example: You need plants for their energy sources and O2….Conversely, plants need you for your energy sources and CO2
  7. Disturbances in Ecosystems:
  8. A Consequence of interconnectedness
  9. Can you think of an example?

II. ECOLOGY OF ORGANISMS

A.BIOTIC AND ABIOTIC FACTORS

  1. Definitions:
  2. Biotic Factors--- All living factors that affect an organism.
  3. Abiotic Factors---All non-living factors that affect an organism (sunlight, water, temperature, wind, rocks, soil…)
  1. The Changing Environment---Abiotic factors are not constant.
  2. Temperature varies from place to place.
  3. Rainfall can change drastically within days
  4. Clouds can affect sunlight
  1. Responses to a Changing Environment
  2. Tolerance
  3. Some bacteria can survive 1100C and some plants can survive –700C, BUT no single organism can survive both of these extremes
  4. What does your body do when you get hot?, get cold? How do you respond? .
  5. An organism cannot live in area where it is exposed to conditions outside of its tolerance limits
  1. Acclimation
  2. Adjusting tolerance to abiotic factors
  3. Training of Olympic athletes in Colorado…just to name one example. RBCs change due to less O2
  4. Not to be confused with adaptation: Acclimation is the change over a lifetime, adaptation is genetic change in a species over many generations …i.e Evolution
  1. Control of Internal Conditions
  2. Conformers: Organisms that do not regulate their internal conditions…they change as their external environment changes. E.g. Reptiles
  3. Regulators: Organisms that use energy to control some of their internal conditions. E.g. Your body temperature stays within a few degrees of 370C or 98.60F
  1. Escape from Unsuitable Conditions:
  2. Dormancy: Organisms enter a state of reduced activity. E.g. Amphibians and Reptiles
  3. Migration: Move to another more favorable habitat. E.g. Birds
  1. Resources:
  2. Energy and materials a species needs
  3. Food
  4. Energy
  5. Nesting sites
  6. Water and sunlight

B.THE NICHE

  1. The way of life or role the species plays in the environment
  2. Fundamental Niche:
  3. Range of conditions a species can potentially tolerate
  4. Range of resources it can potentially use
  5. Realized Niche:
  6. Range of resources the species actually uses
  7. Niche Differences
  8. Generalists---These are species that possess a broad niche. E.g The Opossum, Feeds on anything form fruits and nuts to eggs and dead animals. And is found almost anywhere in the U.S.
  9. Specialists---Species with a narrow niche. E.g. The Koala, feeds only on eucalyptus found in Australia. The Yucca Moth, only uses the Yucca plant to spin its cocoon.
III.ECOLOGY OF POPULATIONS

** A population is a group of organisms that belong to the same species and live in a particular place at the same time.

A.PROPERTIES OF POPULATIONS

  1. Size---How big or small the population is at a given time.
  2. Scientists count members of populations many different ways.

Count numbers of actual individuals

Estimate size by taking samples from different areas

  1. Density:
  2. Measures how crowded a population is.
  3. Expressed in number of individuals per unit area of volume. E.g. The US is 30 people per square km.

Clumped

Even

Random

B.POPULATION DYNAMICS

  1. Birth Rate
  2. Death/Mortality Rate
  3. Life Expectancy
  4. Age Structure
  5. Patterns of Mortality
IV.ECOLOGY OF COMMUNITIES

** A Community is a group of populations interacting. All species interacting is called Symbioses.

APREDATION: A community interaction where one species (Predator) hunts, captures, kills, and consumes another (Prey).

  1. Natural Selection---The old saying “Survival of the fittest.
  2. Mimicry: One species resembles another distasteful, or dangerous one to avoid being eaten, or killed. E.g. King Snake Versus Coral Snake. (Red on Black is a friend of Jack, Red on Yellow will harm a fellow)
  3. Can you think of a few predator/prey relationships?

BPARASITISM: A relationship between organisms in which one organism depends on and harms another organism.

  1. Parasite: The organism that feeds on the other
  2. Host: The organism being eaten or harmed
  3. Endoparasite: Internal parasite that lives in the host’s body. E.g. Bacteria, tapeworms, heartworm…etc…
  4. Ectoparasite: External parasite that lives outside the host’s body. E.g. Flea, ticks, lice, leeches, lamprey, mosquito.
  5. Has its own branch of Biology: Parasitology

CCOMPETITION: Fundamental Niche over-lap…The use of the same limited resource by two or more organisms.

DMUTUALISM: Both species in the relationship benefit.

  1. Bulls Horn Acacia and ants….The flower gets pollinated and the ant has a source of food
  2. Bees and most flowers

ESUCCESSION: The gradual, sequential re-growth of species in an area. In 1988 a good portion of Yellowstone National Park was burned by forest fire. Now it is recovering quite nicely. Vacant lots, parking lots, sidewalks…..What do you see?

  1. Primary Succession: The development of a community in an area that has not supported life previously.
  2. Colonization of new organisms and formation of soil from exposed Rocks.
  3. First organisms are called Lichens ( A fungus that helps make soil by breaking down rock)
  4. Grasses and shrubs begin to grow.
  5. Soil gets richer and deeper, gives rise to larger plants
  6. Larger plants make soil deeper still and shallow rot trees begin to grow (pine)
  7. Broad leaf trees and deeper evergreens (Fir, spruce, Birch)
  8. Hardwoods (Oak, Ash, Maple, Beech, Chestnut)
  9. Climax Community
  1. Secondary Succession: Sequential replacement of a species that follows a disruption in a community. E.g. Forest fire. Can you think of another?
V.ECOSYSTEMS AND THE BIOSPHERE

AENERGY TRANSFER:

  1. Producers: Autotrophs, organisms that can make their own food by way of Chemosynthesis. Make carbohydrates using inorganic compounds….What is a specialized form of chemosynthesis that uses light to make carbohydrates?
  2. Consumers: Heterotrophs, they obtain energy by consuming organic molecules made by other organisms.
  3. Herbivores: Consume Producers
  4. Carnivores: Consume other Consumers
  5. Omnivores: Consume all
  1. Decomposers: Break down the Consumers and Producers into the soil and start the energy flow all over again
  2. Can you think of an example from each category?
  3. Relate the three levels of energy transfer to a food web?