Download Ecosystem

Introduction
to Ecosystems
and Hierarchy
Lecture by: Stephanie Soomar
Lesson Agenda
1. What is Ecology?
2. Levels of Hierarchy
(Organization)
3. Abiotic versus Biotic
4. Habitat versus Niche
What is Ecology?
• is the study of the
interaction of
organisms with
their physical and
biological
environments and
how these
interactions
determine the
distribution and
abundance of the
organisms.
Ecological Hierarchy
Largest to Smallest
• Biosphere
• Ecosystem
• Community
• Population
• Individual
Hierarchy of Organization
• Biosphere—the broadest, most
inclusive, level of organization.
• Consists of the Earth and its
atmosphere. It supports all
life.
• All organisms are found within
the biosphere.
• The biosphere consists on 6
major biomes.
6 Biomes
6 major biomes:
1. Freshwater
2. Marine (Aquatic)
3. Desert
4. Forest
5. Grassland
6. Tundra
Show video: https://www.youtube.com/watch?v=WuejxJttBqo
Ecosystem
An ecosystem
includes all the
living organisms
and the physical
and chemical
factors (nonliving)
which influence
them.
Show video: https://www.youtube.com/watch?v=O3CZFfyed3M
Example: rocky shore
Abiotic versus Biotic
Biotic (living):
Abiotic (non-living):
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fish
algae
insects
bacteria
frogs
turtles
air
- soil
water
- salinity
pH
oxygen
carbon dioxide
temperature
sunlight
pollution
A Marine Ecosystem
• Biotic =
phytoplankton,
zooplankton,
fishes, corals,
crustaceans
Abiotic =
chemicals,
sunlight, water,
currents, pH,
salinity,
sediments
A Terrestrial Ecosystem
• Biotic = trees,
grass, animals,
insects, lichen,
etc.
• Abiotic =
sunlight,
water, soil,
rocks, etc.
Abiotic versus Biotic
• Complete the Abiotic versus Biotic worksheet
Community
• Includes all the
different species
living in a habitat at
the same time.
• Example: the mollusk
community on a
rocky shore, which
would include all the
different species of
mollusks living in this
habitat.
Population
• Consists of organisms of
the same species, usually
defined as living in the
same area.
• Example: a population of
ghost crabs (Ocypode
saratan) living on a sandy
shore.
• The simplest level of
organization in ecology is
that of the individual.
• Individual organism
• Species: is defined as a
group of similar organisms
that can interbreed and
produce fertile offspring.
• Example: skipjack tuna
(Katsuwonus pelamis) and
the red mangrove trees
(Rhizophora mangle)
Individual & Species
Binomial Nomenclature:
• Each species is given a name
consisting of 2 parts.
1. First name: genus or generic
name
2. Second name: species or
specific name
Why are species given 2 part names?
See video on “Interactions Among Organisms” under Marine Ecosystem
videos on flashdrive
Habitat versus Niche
• A habitat is the place where organisms live.
– For example: the area surrounding a hydrothermal vent provides a
habitat for species of tube worms and other specialized organisms
• A niche is the role of an organism within an ecosystem, taking
into account its relationships with other organisms.
– In a marine ecosystem, the niche of a great white shark is the top
predator.
• Organisms which occupy similar niches will tend to compete
with each other for resources, such as food and space to live in
their habitat.
Hydrothermal vents
and tubeworms
The niche of the Great
White Shark is top
predator.
Habitat
• The habitat is the place
where an organism lives out
its life.
– It is where the organism finds
food, shelter and mates.
– Several species can live in the
same habitat but will use the
resources in different ways.
Niche
• A niche is all strategies and
adaptations a species uses in its
environment.
– This is how organisms obtain food,
mates and protection from
predators.
– No two species can occupy the
same niche long (one species will
go extinct).
– “By analogy, it may be said that the
habitat is the organism's ‘address’,
and the niche is its ‘profession’,
biologically speaking.”
http://www.tycho.dk/ezimagecatalogue/catalogue/variations/1150-250x250.jpg
Habitat vs. Niche
A niche is determined by the tolerance
limitations of an organism, or a limiting
factor.
Limiting factor: Any biotic or abiotic
factor that restricts the existence of
organisms in a specific environment.
Habitat vs. Niche
Examples of limiting factors1. Amount of water
2. Amount of food
3. Temperature
Which level is it?
• Identify the level of ecological
organization represented by each
picture.
• A herd of buffalo.
Which level is it?
• All of the living and non-living
items in a pond
Which level is it?
• All of the animal populations
living on the African savannah.
See video: https://www.youtube.com/watch?v=BzU701O88e8