The Ecosystem: Interrelationships between organisms and the environment - PowerPoint PPT Presentation

1 / 21
About This Presentation
Title:

The Ecosystem: Interrelationships between organisms and the environment

Description:

The Ecosystem: Interrelationships between organisms and the environment ... Grasshopper eaten by frog. Impact of pesticides (i.e., DDT) on the species of an ecosystem ... – PowerPoint PPT presentation

Number of Views:749
Avg rating:3.0/5.0
Slides: 22
Provided by: peterakw
Category:

less

Transcript and Presenter's Notes

Title: The Ecosystem: Interrelationships between organisms and the environment


1
The Ecosystem Interrelationships between
organisms and the environment
  • 1. Should we care about the survival of organisms
    other than human beings?
  • 2. Can we humans live alone and survive on the
    planet?
  • 3. Does the way nature operates offer solutions
    to our environmental problems?

2
Definition of Terms 1
  • Ecology A study of the interrelationships
    between living organisms and the non-living
    components and processes that make up the global
    environment.
  • Biosphere The worldwide system within which all
    life functions. It includes the atmosphere (air),
    hydrosphere (water) and the lithosphere (soils,
    rocks)
  • Biome A major ecological region within which
    plant and animal species are similar in general
    characteristics and in their relationships to the
    physical environment. E.g.. Tundra, Deserts,
    Forests Grasslands etc.

3
Definition of terms2
  • Ecosystem A collection of living organisms in a
    geographic area, together with the non-living
    things with which they interact.
  • Aquatic Ecosystems (water-based systems)
  • Terrestrial Ecosystems (land-based systems).
  • Population A group of organisms of the same kind
    living in a given area.
  • Natural Community Populations of different
    species living together and interacting in a
    given area.
  • Habitat The environment in which a particular
    organism lives in the community

4
Definitions3
  • Ecological Niche An organisms role within a
    community.
  • Environment Comprises all the surrounding things
    that affect an organism or a community of
    organisms in a given area.

5
The Structure of Ecosystems1
  • Components of an Ecosystem
  • Biota or Biotic component the living organisms
    comprising all plants animals
  • Abiotic component the non-living physical and
    chemical components consisting of wind,
    temperature, water, soil, precipitation which the
    biotic elements need to survive.

6
Structure of an Ecosystem2
  • A single abiotic factor most lacking in a
    particular environment is termed, a Limiting
    Factor. E.g. water-desert, temperature-tundra
  • The variation in physical factors that an
    organism can withstand and continue to thrive in
    an environment is termed - Range of Tolerance

7
Producers in an Ecosystem
  • Categories of Organism in an ecosystem
  • Autotrophs self-nourished species (e.g. plants)
  • Heterotrophs other-nourished species (humans
    and animals)
  • 1. Producers Green Plants responsible for
    photosynthesis and the release of energy into an
    ecosystem.

8
Consumers and Decomposers
  • 2. Consumers
  • a) Primary Consumers - Herbivores
  • b) Secondary Consumers Carnivores
  • c) Tertiary Consumers - Carnivores
  • d) Multiple-level Consumers - Omnivores
  • 3. a) Detritivores e.g. crab, vulture, termites
  • b) Decomposers e.g. fungi and bacteria

9
The Food Chain
  • A food chain or food web is represented by a
    sequence of organisms through which energy and
    nutrients flow from one organism to another.
  • A major step in the transfer of energy through
    the food chain is termed as a Trophic level
  • Primary consumers First trophic level
  • Secondary consumers - Second trophic level
  • Tertiary Consumers - Third trophic level
  • The amount of usable energy in the food chain
    decreases as we move down the trophic level

10
An example of a marine food chain
  • Phytoplankton is the first level of marine
    food chain Zooplanktons are eaten by krill and
    other Small fish which are all eaten in turn by
    Big fish, including penguins, seals and whales.
    The marine food chain continues when these big
    fishes are eaten by Mammals like polar bears

11
A marine food chain
  • A marine food chain
  • Polar bear - 5
  • Seal - 4
  • Cod - 3
  • Krill - 2
  • Algae - 1

12
A terrestrial-based food chain
  • A Terrestrial food chain
  • Hawk
  • Snake eaten by hawk
  • Frog eaten by snake
  • Grasshopper eaten by frog

13
Impact of pesticides (i.e., DDT) on the species
of an ecosystem
14
Interactions among species in an Ecosystem
  • Plants compete amongst themselves for
  • 1. water, 2. nutrients 3. sunlight and 4. space
  • Animals compete over
  • 1. food, 2. water, 3. mating and 4. territory
  • 2 main types of relationships
  • Predation one species (the predator) feeds on
    the other (prey) e.g. cat and mouse
  • Symbiosis species live in an intimate
    association with each other

15
Types of symbiotic relations
  • Parasitism - one species feeds on another (the
    host) and may kill it.
  • Mutualism both parties benefit equally from the
    relationship (flowers and butterflies)
  • Commensalism the relationship benefits one
    species but neither helps nor harms the other

16
Principles of Ecology
  • First Law of Energy energy can be converted
    from one form to another but cannot be created or
    destroyed
  • Second Law of Energy whenever energy is
    converted from one form to another, a certain
    amount is lost in the form of heat.
  • The Law of Conservation of Matter
  • Although matter can be changed from one form to
    another it can neither be created nor destroyed
    by ordinary physical and chemical changes.

17
Biogeochemical Cycles
  • Comprise processes through which elements that
    sustain life (water, carbon, phosphorus and
    nitrogen) are continuously made available to
    living organisms.
  • Nitrogen cycle
  • Hydrological cycle
  • Carbon cycle
  • Phosphorus cycle

18
The Hydrological Cycle
19
The Carbon Cycle
20
Interruptions in an Ecosystem
  • Causes
  • a) Natural causes volcanic eruptions
  • b) Human causes e.g. construction, agriculture,
    mining, etc.
  • List some of the consequences that can result
    from an abrupt interruption in the smooth
    functioning of an ecosystem?

21
What lessons can we learn from the way a natural
ecosystem operates?
  • Natural ecosystems gain resources, use it and
    dispose of wastes through recycling.
  • Ecosystems sustain themselves by running on Solar
    Energy which is exceedingly abundant,
    nonpolluting, constant and long lasting.
  • Far less of Carnivores can be supported by each
    ecosystem. Many would soon face extinction
  • Every species in a community play an important
    role in the sustenance of the ecosystem
Write a Comment
User Comments (0)
About PowerShow.com