Ecology

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Ecology

• Lesson 9.1

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• Lesson Objectives
• Distinguish between abiotic and biotic factors.
• Describe ecological levels of organization in the
  biosphere.
• Define organism, population, community,
  ecosystem, biome, and biosphere as the term are
  used in ecology and other ecological concepts.
• Compare and contrast exponential and logistic
  growth.
• Compare and contrast niches and habitats.

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Introduction

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Levels of Organization

• Ecologists study organisms and their environments
  at different levels of organization

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• Organisms are individual living things.
• This is the lowest level of organization that
  ecologists study. Biologists study organisms,
  organ systems, organs, tissues, cells,
  organelles, and molecules. Chemists study atoms
  and subatomic particles.

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Organisms and the Environment

• Organisms life form consisting of one or more
  cells has characteristics of life.
• Environment includes both living (biotic) and
  nonliving things (abiotic).

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Biotic and Abiotic Factors

• Biotic? living organisms
• Abiotic? nonliving or physical factors
• Together determine productivity of the ecosystem
  in which organisms live

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What Is a Population?

• In biology, a population is a group of organisms
  of the same species that live in the same area,
  interact with one another, and produce fertile
  offspring.
• .How large a population is and how fast it is
  growing are often used as measures of its health.

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What Is a Community?

• Communities are made up of populations of
  different species that live in the same area and
  interact together.

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What Is an Ecosystem?

• An ecosystem is a unit of nature and the focus of
  study in ecology. It consists of all the biotic
  and abiotic factors in an area and their
  interactions. Ecosystems can vary in size.
• A lake could be considered an ecosystem. So could
  a dead log on a forest floor. Both the lake and
  log contain a variety of species that interact
  with each other and with abiotic factors.
  

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Ecosystem Components

• Niches
• Habitats
• Competitive Exclusion Principle

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The Niche

• Niche? organisms occupation (role), where it
  lives, and way in which organisms use conditions
  they exist in
• Food it eats
• Place in food web
• How it gets food
• Range of temperatures
• needed for survival
• When and how it
• reproduces

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The Habitat

• Physical environment to which an organisms has
  become adapted and survives in.

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Competitive Exclusion Principle

• Two different species
• cannot occupy the
• same niche in the
• same geographic area.
• If they do they will compete
• with one another for the
• same food and other resources.
• Eventually, one species will
• out compete the other.

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What Are Biomes?

• A biome is a group of similar ecosystems with the
  same general abiotic factors and primary
  producers.
• Biomes may be terrestrial or aquatic.

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What Is the Biosphere?

• The biosphere is the global sum of all
  ecosystems integrating all living beings and
  their relationships, including their interactions
  with the elements of the lithosphere,
  hydrosphere, and atmosphere.
•  

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Lesson Summary

• Ecology is the study of how living things
  interact with each other and with their
  environment. The environment includes abiotic
  (nonliving) and biotic (living) factors.
• Organisms are dependent upon their environments
  for energy and matter.
• Population growth rate is how fast a population
  changes in size over time. It is determined by
  rates of birth, death, immigration, and
  emigration.
• Under ideal conditions, populations can grow
  exponentially. The growth rate increases as the
  population gets larger. Most populations do not
  live under ideal conditions and grow logistically
  instead. Density-dependent factors slow
  population growth as population size nears the
  carrying capacity.
• A community is the biotic part of an ecosystem.
  It consists of all the populations of all the
  species that live in the same area. It also
  includes their interactions.
• An ecosystem consists of all the biotic and
  abiotic factors in an area and their
  interactions. A niche refers to the role of a
  species in its ecosystem. A habitat is the
  physical environment in which a species lives and
  to which it is adapted. Two different species
  cannot occupy the same niche in the same place
  for very long.
• The biosphere is composed of all the ecosystems
  on Earth.