Transcript The Kingdom protista

Mr. Wright, 2010
CH. 20: THE KINGDOM PROTISTA
Sections 20.1 – 20.5
INTRODUCTION TO PROTISTS
Question #1:
THE KINGDOM PROTISTA IS OFTEN REFERRED
TO AS A “CATCH-ALL” KINGDOM. WHAT ARE
SOME REASONS FOR THIS?
PROTISTA – A DIVERSE KINGDOM
Some are autotrophs, some are heterotrophs.
 Some are unicellular, some are multicellular.
 Some have cell walls, some do not.
 Some reproduce asexually, some sexually.


There is a huge amount of variety within this
kingdom – it’s basically made up of organisms
that don’t fit anywhere else.
PROTISTA – A DIVERSE KINGDOM
Question #2:
WITH SO MANY DIFFERENCES BETWEEN ALL
THE DIFFERENT PROTISTS, HOW DO WE EVEN
DECIDE WHAT GOES IN THIS KINGDOM?
PROTISTS – THE FIRST EUKARYOTES
 All
protists are eukaryotes that simply
don’t fit as fungi, plants, or animals.
 Scientists
believe that modern day
fungi, plants, and animals evolved
from protist ancestors long, long ago.
Question #3:
WE DIVIDE PROTISTS INTO THREE MAIN
GROUPS. WHAT ARE THESE GROUPS, AND WHAT
TRAIT DO WE USE TO CLASSIFY PROTISTS INTO
THESE GROUPS?
THE THREE GROUPS OF PROTISTS

Protists are divided into three main groups
based on how they obtain nutrients
Animal-like: capture and eat other organisms
 Plant-like: get energy from photosynthesis
 Fungus-like: absorb nutrients from their
environments

Question #4:
ANIMAL-LIKE PROTISTS: THE PROTOZOA
ANIMAL-LIKE PROTISTS

Animal-like protists are often called protozoa.
 Protozoa

= “first animals”
Divided into four groups based on how they
move:
 Zooflagellates
 Sarcodines
 Ciliates
 Sporozoans
ZOOFLAGELLATES

Zooflagellates move using a flagella.
 Flagella

– a long, thin tail fiber.
Zooflagellates whip the tail around like a
propeller, moving them through their
environment.
SARCODINES - AMOEBOIDS

Amoeboid protists move using pseudopodia.
 Psuedopodia
= “false feet”
 Extensions of the cell used for movement and for
taking in food particles.
 Cytoplasm flows into the pseudopod, moving the
cell in any direction.
CILIATES

Ciliates move using cilia.
 Cilia

– short hairs
Ciliates beat their cilia back and forth like the
oars of a row boat, propelling them through
their environments.
SPOROZOANS
Sporozoans cannot move on their own.
 They are parasites with complex life cycles
often involving many different hosts.
 The best example is Plasmodium, which causes
malaria.

REVIEW OF KEY CONCEPT

Two protozoa can come together and exchange
genetic material with each other.
Anyone remember what this process is called?
(Hint: bacteria could do it)
 CONJUGATION… you may want to make a note for
yourself in the margin if you didn’t remember.

Question #5:
PLANT-LIKE PROTISTS: ALGAE
PLANT-LIKE PROTISTS
Plant-like protists are often referred to as algae.
 Every protist in this group obtain their energy
through photosynthesis, just like plants do.
 Some (but not all) even appear to have roots,
stems, and leaves like plants.

PLANT-LIKE PROTISTS
 So,
why are they protists and not
plants?
Some are motile.
Different cell walls.
Lack complex tissue layers found in
plants.
Question #6:
MANY PROTISTS GO THROUGH ALTERNATION OF
GENERATIONS. WHAT DOES THIS MEAN?
WHAT IS ALTERNATION OF GENERATIONS?

Alternation of generations – within the life cycle
of an organism, the occurence of two or more
distinct forms that differ from each other in
method of reproduction

In English, please?
 It
just means that an organism goes through
asexual reproduction at one point in it’s life, and
sexual reproduction at another point.
ALTERNATION OF GENERATIONS

Notice how the protist above has both a sexual
and asexual phase, and spends time as haploid
and diploid cells.
Question #7:
FUNGUS-LIKE PROTISTS: THE SLIME MOLDS
FUNGUS-LIKE PROTISTS: SIMILARITIES
Fungus-like protists absorb their nutrients from
their environments.
 Fungus-like protists reproduce by releasing
spores, just like fungi.

FUNGUS-LIKE PROTISTS: DIFFERENCES
Fungus-like protists have centrioles in their
cells, while true fungi do not.
 Fungus-like protists have different cell walls (no
chitin) than true fungi do.

Question #8:
LET’S MAKE A VENN DIAGRAM COMPARING THE
THREE GROUPS OF PROTISTS TO ONE ANOTHER.
Key Concept:
ALTERNATION OF GENERATIONS
REVIEW: LIFE CYCLES

Let N = the number of chromosomes offspring
gets from each parent.
 Each
gamete (sex cell) has N chromosomes, are
haploid.
The offspring formed when two gametes come
together, then, is 2N… diploid.
 Your body will make gametes using meiosis.

 Remember,
cells resulting from meiosis have half
as many chromosomes… thus, our gametes are N.
TYPICAL ANIMAL LIFE CYCLE
HAPLOID ADULTS

Not all organisms have life cycles similar to our
own, however… some are actually haploid(N) as
adults instead!

Spores - haploid cells that are capable of
growing into haploid adults.
HAPLOID VS DIPLOID ADULTS
The
main thing that determines
whether adults are haploid or
diploid is what meiosis creates!!!
Does
it produce gametes, or
spores?
Remember,
meiosis cuts the
number of chromosomes in half!
DIPLOID ADULTS
HAPLOID ADULTS
COMPARING THE TWO LIFE CYCLES
ALTERNATION OF GENERATIONS

Many protists, fungi, and plants undergo
alternation of generations.
 Some
generations of adults are haploid, some
generations of adults are diploid.
ALTERNATION OF GENERATIONS

The different generations of adults might look
and act completely different from one another…
they may even seem like different species at
first!
 One

may be motile, one may be sessile.
Also note that the exact life cycle will vary from
organism to organism – not all alternate
generations in the same way!
 …but
you should still have an idea what this means.
Sections 20.1 – 20.5
PROTISTS IN THE REAL WORLD
MALARIA
Malaria kills up to 2 million people every year.
 Caused by Plasmodium, carried by mosquitos.

Symptoms: chills, fever, death
 Very resistant to drug treatment.

AFRICAN SLEEPING SICKNESS
Caused by Typanosoma.
 Symptoms: chills, fever, rashes.
 Eventually the patient loses consciousness,
falling into a sleep that may be fatal.

AMOEBIC DYSENTERY
Caused by Entamoeba.
 Lives in the intestines and absorbs food from
the host.
 Also destroys the intestinal tissue itself
resulting in bleeding.
 Spread through feces.

PROTISTS AND TERMITES
Termites themselves cannot digest cellulose
(wood).
 They have huge colonies of protists that live
inside of their gut that do it for them.
 You can actually squish a termite under a
microscope and see them!

RED TIDES
Sometimes, when conditions are right, algae
populations in an environment will skyrocket.
This is called an algal bloom.
 Can be problematic because they can take
nutrients and/or oxygen out of the water, killing
fish and invertebrates. Some even produce
toxins!

ALGAE AND THE OCEANS

All bad news aside, algae is extremely
important to the Earth’s aquatic environments.
 Make
up the bottom of the food chain.
 Provide much of the Earth’s oxygen.
OTHER USES FOR ALGAE:
THE IRISH POTATO FAMINE