Download Chapter 1

Unit 2
Ecosystems and Their Diversity
Classifying and Naming Organisms
‹
Organisms are sorted into a hierarchical
system, starting with the broadest category—
domain—and progressing through kingdom,
phylum, class, order, family, and genus to the
most specific category—species.
Group
Bobcat’s
classification
Organisms that can be included in this group
domain
Eukarya
euglena, mushroom, lodgepole pine, earthworm, starfish,
bee, shark, horse, oyster, frog, dog, cougar, lynx, house
cat, bobcat
kingdom
Animalia
earthworm, starfish, bee, shark, horse, oyster, frog, dog,
cougar, lynx, house cat, bobcat
phylum
Chordata
shark, horse, frog, dog, cougar, lynx, house cat, bobcat
class
Mammalia
horse, dog, cougar, lynx, house cat, bobcat
order
Carnivora
dog, cougar, lynx, house cat, bobcat
family
Felidae
genus
Lynx
lynx, bobcat
species
rufus
bobcat
cougar, lynx, house cat, bobcat
‹
‹
The classification system that is most commonly
used today has three domains and a number of
kingdoms.
The three domains used to classify organisms are
Bacteria, Archaea, and Eukarya.
Bacteria
Eukarya
Archaea
• Prokaryotic, unicellular
organisms
• Lack a membranebounded nucleus
• Reproduce asexually
• Heterotrophic by
absorption
• Autotrophic by
chemosynthesis or by
photosynthesis
• Move by flagella
• Eurkaryotic, unicellular to
multicellular organisms
• Membrane-bounded
nucleus
• Sexual reproduction
• Phenotypes and nutrition
are diverse
• Each kingdom has
specializations
• Flagella, if present, have a
9 + 2 organization
• Prokaryotic, unicellular
organisms
• Lack a membranebounded nucleus
• Reproduce asexually
• Many are autotrophic by
chemosynthesis; some
are heterotrophic by
absorption
• Unique rRNA base
sequence
• Distinctive plasma
membrane and cell wall
chemistry
‹ The
four kingdoms within the domain
of Eukarya are Protista, Fungi,
Plantae, and Animalia.
‹
Scientists use binomial nomenclature to
name organisms. The two-part scientific
names include the organism’s genus and
species, usually in Latin.
The scientific name for
lodgepole pine is
Pinus contorta
Genus
Genus
species
species
‹
A dichotomous key is a branched or
stepped process that can be used to
identify organisms.
Studying Organisms in Ecosystems
In this section, you will
‹
‹
‹
‹
‹
identify biotic and abiotic characteristics and
explain how they affect ecosystems
explain how ecosystems contain a variety of
niches and habitats to support diverse organisms
explain how limiting factors can affect the
distribution and size of a population
research the impacts of an introduced species
explain the use of sampling techniques
Information
‹ Energy
from the sun drives air
currents that distribute H2O vapour
‹ Wind interacts with land features
forcing air upwards where it is cooled
and loses moisture as precipitation
‹ The interior of a continent will
experience less rain as well as higher
latitudes
‹ Biomes
are classed by one of the
following:
– One system uses the climate zone
system. Uses annual temperature and
precipitation to establish boundaries of
climatic zones
– The other system defines it on the basis
of vegetation structure along with
average temperatures and vegetation
‹
Abiotic factors such as climate, latitude,
elevation, temperature, humidity,
moisture, salinity, and light affect patterns
of distribution of life.
• A habitat is a place or area within a biome or
ecosystem that has a particular set of biotic
and abiotic characteristics.
• Its predominant life forms will characterize the
type of ecosystem – forest, desert, coral reef
• An organism’s range is the geographical area
where the organism is found.
The
The hoary
hoary marmot
marmot (Marmota
(Marmota
caligata)
caligata) feeds
feeds on
on plants
plants found
found in
in
high
high altitude
altitude meadows.
meadows.
Range
Range of
of the
the hoary
hoary marmot
marmot
‹
‹
The ecological niche of a population is the role
that its members play in an ecosystem.
The variety of niches and habitats within an
ecosystem allow it to support a diversity of
organisms.
These
These two
two species
species of
of ocean
ocean
barnacles
barnacles have
have similar
similar niches,
niches, but
but
the
the two
two niches
niches differ
differ enough
enough that
that
both
both species
species are
are able
able to
to establish
establish
populations
populations at
at different
different depths
depths of
of
the
the rocky
rocky shore.
shore.
‹
A limiting factor is any biotic or abiotic element
that controls the number of individuals in a
population. Biotic limiting factors include
competition, predation, and parasites.
Limiting
Limiting factors
factors prevent
prevent
these
these bacteria
bacteria from
from
reproducing
reproducing infinitely.
infinitely.
Populations:
‹ Populations
fluctuate depending on:
‹ Density Dependant
– As populations grow and reach their
carrying capacity, competition increases
– This in turn result in decreased birth
rate, increased death rate and increased
toxin accumulation!
‹ Density
Independent
– These would be our environmental
changes – forest fires, floods, drought,
volcanic eruptions!
Types of Population Curves
‹
Under ideal
conditions a
population will
continue to grow
exponentially
(J-curve)
‹
No growth curve
can continue to
grow indefinitely
(S-curve)
‹ Carrying
capacity of an ecosystem is
the largest population an
environment can support – it is
determined by the factors of
predation, competition, migration,
and climate changes
‹ Occasionally populations will explode
due to a time lag – then it will crash
dramatically!
‹
Organisms can be sampled using transects
or quadrats situated randomly in a sample
area. From these samples, the density of
a population can be estimated.
A
A 5m
5m ×× 100m
100m transect
transect
Unit Review
‹
‹
‹
‹
‹
‹
What system do scientists use to name
organisms?
What are the levels in the hierarchical system
into which organisms are grouped.?
What are the three domains of life? What are
some of their characteristics?
What is a habitat? How does it differ from a
niche?
Give three examples each of biotic and abiotic
limiting factors.
What techniques are used to determine
population size?
Concept Organizer
Chapter 3 Summary
‹
‹
An organism’s environment includes biotic and
abiotic components. Organisms affect and are
affected by their environment. Organisms are
part of a population, a community, an
ecosystem(s), and Earth’s biosphere. Abiotic
factors in the environment affect the distribution
of organisms.
Biologists use a hierarchical system to group
organisms. Naming and categorization must
sometimes be changed to accommodate new
discoveries. A universal, two-word naming
system is used, giving each organism a genus
and species name in Latin.
Summary (cont’d)
‹
‹
‹
‹
Biologists use dichotomous keys to identify
organisms. Each step in the key has only two
choices.
Unequal heating of the Earth creates different
climates and distinct biomes that support the
growth of certain groups of organisms. Within
biomes and ecosystems, there is a great deal of
variation in habitats and niches.
A population’s growth in a particular habitat is
limited by biotic and abiotic factors.
Biologists use sampling techniques to estimate
population size in large ecosystems. Transects
are often used for mobile populations, while
quadrats are used for sessile populations, such as
plants.