Human versus Amoeba
How multicellular and
unicellular organisms carry
out their life processes.
What do all life forms on earth have
in common?
The Life Processes.
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Nutrition
Transport
Respiration
Growth
Synthesis
Regulation
Excretion
Reproduction
Notes
All organisms, big and small, must
carry out the same basic life
processes. Some do this with complex
organ systems, while others manage
just as well using only their cellular
organelles. Today we will compare
how two very different organisms
manage to get the job done.
The Human Being
Large, multicellular
animal in the phylum
Chordata.
Possesses many
advanced and complex
organ systems.
Perhaps the pinnacle of
animal evolution.
All activity is coordinated
by a complex brain and
nervous system.
The Amoeba
A simple unicellular
protist in the phylum
Protozoa.
One of the simplest
animal-like microbes on
earth.
Successful, and relatively
unchanged for hundreds
of millions of years.
All the activities within the
amoeba are coordinated
by the nucleus.
Comparison 1: Nutrition
Nutrition: The
obtaining and
processing of food
materials.
Both human and
amoeba are
heterotrophes, which
means they cannot
produce their own
food, like a plant.
Nutrition continued
The human has strong
teeth and powerful jaw
muscles that help them
physically break down
their food.
Once ingested, the food
moves through a complex
digestive system where
organic molecules are
hydrolyzed into molecules
small enough to be
absorbed into the equally
complex circulatory
system.
Nutrition continued
The amoeba extends its
cell membrane to
surround and then engulf
its food.
The food is then stored in
a vacuole.
A lysosome will then
inject enzymes into the
vacuole, which digests
the food.
The small organic
molecules then diffuse
into the cytoplasm.
Nutrition: Summary
Both the human and the amoeba obtain
food from other organic sources.
The human utilizes their digestive,
circulatory and musculo-skeletal systems
to accomplish this.
The Amoeba relies upon its cell
membrane, vacuoles and lysosomes to do
the same thing.
Comparison 2: Transport
Transport: The intake
and distribution of
food materials.
Humans need to
distribute nutrients to
every one of their
billions of cells.
For Amoeba, the
nutrients only need to
diffuse throughout
their cytoplasm.
Transport continued
In humans, nutrients
are carried throughout
the body by means of
blood flowing through
an extensive
circulatory system.
Powering this flow of
blood this a muscular,
four chambered heart.
Transport continued
For the amoeba, the
digested nutrients
disperse throughout
the cytoplasm by
means of diffusion
and cyclosis.
Cyclosis is the term
used to describe the
streaming motion of
the cytoplasm within
the cell.
Transport summary
For humans, transport is achieved through
the use of blood contained in the
thousands of miles of blood vessels that
make up the circulatory system. All of this
is put into motion by the constant beating
of a muscular heart.
Amoeba transport their nutrients through
their cytoplasm by simple diffusion and
cyclosis, or cytoplasmic streaming.
But wait!!!
Didn’t we learn that the endoplasmic reticulum
helps to transport certain molecules throughout
a eukaryotic cell such as an amoeba?
Yes, we did, but we will see why the
endoplasmic reticulum, while transporting
proteins and lipids, does more than transport
molecules.
This will be less confusing to you when we
discuss synthesis.
Comparison 3: Respiration
Respiration: The
process by which the
energy contained in
food is released
through the process
of oxidation.
Respiration occurs
between the double
membrane of the
mighty mitochondria.
Respiration continued
Many different systems
play a role in human
respiration. The
respiratory system
introduces oxygen into
the body, the digestive
system breaks down food
so it can pass into blood
stream, and the
circulatory system carries
both nutrients and oxygen
to all the cells of the body.
Respiration continued
We have already covered
how the amoeba gets its
nutrition, but how about
the oxygen necessary for
respiration?
The amoeba relies on the
passive transport of
oxygen through its cell
membrane. Once in the
cell, the oxygen diffuses
in the cytoplasm until its
concentration is in
equilibrium throughout
the amoeba.
Respiration summary
The human relies on the interaction of
many different body systems to carry out
respiration. The respiratory, circulatory,
digestive and musculo-skeletal systems all
play a part.
In amoeba, it is many organelles that get
the job done. The cell membrane, the
cytoplasm, vacuoles and lysosomes are all
involved in this process.
Comparison 4: Growth
Growth: The increase
in the size on an
organism.
All life on earth
increases in size
during their lifetime,
but they do not all
follow the same
pattern.
Growth continued
Humans depend on
interactions between
their Endocrine,
Digestive, Musculoskeletal and Nervous
systems to control
growth.
Humans stop growing
at adulthood.
Growth continued
Amoeba are in a near
constant state of growth
and division.
Immediately after cell
division, the nucleus
coordinates the
production of more
cytoplasm and cell
organelles, causing an
increase in size.
The ribosome, the
nucleolus and the
mitochondria all help the
amoeba to grow following
mitosis
Growth summary
At some point in their life time, all organisms will
undergo growth of some type.
Some animals, such as fish and reptiles
continue to grow throughout their lives.
Birds and mammals grow until they reach
adulthood, at which point they stop growing.
Amoeba go through continuous cycles of growth
and division.
Comparison 5: Synthesis
Synthesis: The
process by which
simple compounds
are combined to
make more complex
molecules.
Most synthesis
involves the creation
of proteins from
amino acids.
Synthesis continued
In humans, the digestive,
circulatory, musculoskeletal and respiratory
systems work together to
deliver nutrients to all the
cells of the body.
Not all of these nutrients
are used for energy,
some, are used to build
cell organelles and other
body structures.
Synthesis continued
Amoeba also use the nutrients
not used for energy production
to build their organelles.
Protein synthesis occurs at the
ribosomes. The endoplasmic
reticulum transports these
proteins throughout the cell.
The Golgi bodies help
assemble and package lipids.
The information on
constructing proteins is stored
in the DNA, which is found in
the nucleus.
Synthesis summary
All life must assemble more complex
compounds from the nutrients contained in their
food.
Like all life processes, synthesis occurs in the
cell.
Human and amoeba supply their cells with the
necessary components for synthesis in the same
manner as they do for respiration. In both cases
similar organ systems and organelles are
involved in the ingestion, digestion and
transporting of nutrients.
Comparison 6: Regulation
Regulation: The
coordinated response
by an organism to a
changing
environment.
The principal function
of regulation is to
maintain homeostasis
Regulation continued
Humans respond to their
changing environment by
means of several of their
organ systems.
Sweating (Excretory)
“Flight or Fight” response
(Endocrine)
Shivering (Musculoskeletal)
Reflex actions (Nervous)
Can you think of any
other examples?
Regulation continued
Amoeba do not have the
complex systems to help
them regulate.
Amoeba will use their
cytoplasm and cell
membrane to create
psuedopods to move to a
more tolerable
environment.
They will move away from
heat, cold or predators.
Regulation summary
All organisms must be able to respond to a
changing environment in order to maintain
homeostasis.
When homeostasis is not maintained, an
organism can become sick. If the organism is
not able to regulate its internal environment for
an extended period of time, it will die.
Amoeba are unable to regulate certain features
of its internal environment, such as
temperature, without changing its location.
Comparison 7: Excretion
Excretion: The
removal of metabolic
wastes from an
organism.
All of the life
processes have two
things in common.
– They require energy
– They produce waste
Excretion continued
In humans, metabolic
wastes are
transported out of the
body by means of the
excretory system.
This system functions
through the
coordinated actions of
the liver, kidneys and
urinary system, skin
and lungs.
Excretion continued
Amoeba have no
excretory system or
anything like it.
In an amoeba, metabolic
wastes diffuse out of the
cytoplasm, through the
cell membrane and into
the surrounding
environment.
Some species of amoeba
have special contractile
vacuoles which pump out
extra water.
Excretion summary
All of the life processes require energy and
produce waste products.
In humans, those waste products include salts,
urea, carbon dioxide and water.
If the waste products are not promptly removed
from the body they can become toxic, and make
the organism sick, or even cause its death.
In unicellular organisms, metabolic wastes
diffuse through the cell membrane.
Comparison 8: Reproduction
Reproduction: The
process by which
offspring are produced.
This life process is
different from the others
in that it is not required
for an individual
organism.
Reproduction must occur
or a species will become
extinct.
Reproduction continued
Humans reproduce
sexually, which means
the offspring receive half
of their genetic material
from each parent.
Both males and females
have specialized
reproductive systems
which produce gametes.
The reproductive system
works in conjunction with
the endocrine and
nervous systems.
Reproduction continued
Amoeba are asexual,
which means there is only
one parent, and the
offspring are genetically
identical to the parent.
Asexual reproduction is
mediated by the nucleus.
Amoeba reproduce by a
mitotic process called
binary fission, which
results in two cells of
equal size.
Reproduction summary
All species must reproduce or they will become
extinct.
Humans reproduce sexually, which increases
the amount of genetic diversity within the
species.
Amoeba reproduce asexually. The only way the
genetic material of the offspring can be different
from that of the parent is through mutation.
The lack of diversity in asexually reproducing
organisms is offset by the rate at which they can
multiply.
Final Analysis
As we learned in the beginning of the year,
all organisms must carry out the 8 life
processes in order to survive. While there
are many differences between the many
different forms of life on earth, there are
also some great similarities. Among these
is the genetic material that determines the
shape and behavior of all life. No matter
how different two organisms may be,
D.N.A. is D.N.A.
Until next time, Adios Amoebas!!