Download Protists and Fungi

There
will be no grades
given out until this Friday.
Please do not ask!
HW-Read 11-1 and do the
section review on page
273, questions 1-10 due
Wed. Use spiral notebook.
A protist is a member of the Kingdom
Protista.
 All protists are eukaryotes, which means
that their cells have a nucleus. They are less
complex than other eukaryotic organisms.
 Protista are related more by how they differ
than how they are similar.
 Some scientists think that Kingdom Protista
should be divided into several kingdoms

Protists are very diverse and have few
traits in common.
 Some protists control their own
movement, others cannot
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Some protists produce their own food.
They are producers.
 Some eat other organisms.
 Some eat decaying matter.

The protists that must get their food from
their environment are heterotrophs.
 Many heterotrophs eat small living
organisms, such as bacteria, yeast or
other protists.
 Some are decomposers and eat
decaying matter.
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Some protists get
energy in more than
one way.
Slime molds get
energy by engulfing
both small organisms
and particles of
organic matter.
Some heterotrophs are parasites.
 An organism that a parasite invades is
called a host.
 Parasites cause harm to their host.
 They may invade fungi, plants or animals.
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During the mid
1800’s, a parasitic
protist wiped out
most of the potatoes
in Ireland.
Many people died of
starvation.
Like all living things, Protist reproduce.
 Some reproduce sexually.
 Most reproduce asexually, by binary
fission, like Euglena.
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Binary fission is reproduction in which one
single-celled organism splits into two
single-celled organisms.
 Some single-celled protists use multiple
fission to make more than two offspring
from one parent.
 Each new cell is a single-celled protist.

Sexual reproduction requires two
parents.
 Member of the genus Paramecium
sometimes reproduce sexually by a
process called conjugation.

During conjugation two individuals join
together and exchange genetic
material by using a small second
nucleus.
 Then they divide to produce four protists
that have new combinations of genetic
material.

Many protists can reproduce sexually
and asexually.
 In some protist producers, the kind of
reproduction alternates by generation.
 A parent will reproduce asexually, and its
offspring will reproduce sexually.
 Other protists reproduce asexually until
environmental conditions become
stresssful, lack of water or food, and then
they will use sexual reproduction.

Some protists have complex
reproductive cycles.
 These protists may change forms many
times, such as the Plasmodium Vivax,
which causes malaria.

 Do
you know what algae is? Have you
ever seen it? What does it look like?
Algae needs a lot of water in order to
live. Where do you suppose most
algae live?
 Record
and illustrate your answers in
your science journal.

Protists are organized into three groups
Producers
 Heterotrophs that can move
 Heterotrophs that cannot move

Red algae
 Green algae
 Brown algae
 Diatoms
 Dinoflagellates
 Euglenoids
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Many protists are
producers which use
the sun’s energy to
make food through
photosynthesis.
These protist
producers are
known as algae.
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All algae have the
green pigment
chlorophyll, which is
used for making
food.
Most algae have
other pigments that
give them a color.
Most algae live in
water.
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Some algae are
made of many cells.
Many-celled algae
generally live in
shallow water along
the shore. You know
these algae as
seaweeds.
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Free floating singlecelled algae are
called
phytoplankton.
These algae cannot
be seen without a
microscope.
They float near the
water’s surface.
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Phytoplankton
provide food for
most other organisms
in the water.
They also produce
much of the world’s
oxygen.
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Most of the world’s
seaweeds are red
algae.
Red algae live in
tropical oceans,
attached to rocks or
other algae.
Red algae are
usually less than 1 m
in length.
The green algae are
the most diverse group
of protist producers.
 They are green
because chlorophyll is
the main pigment in
their cells. Most live in
water or moist soil.
 Others live in snow,
tree trunks and inside
other organisms.
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Many green algae
are single celled.
Individual cells of
green algae, like
Volvox, live in groups
called colonies.
Most of the seaweeds
found in cool climates
are brown algae.
 They attach to rocks or
form large floating
beds in ocean waters
with only the top part
exposed to sunlight.
 They have chlorophyll
and a yellow-brown
pigment.
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Diatoms are singlecelled, found in both
salt water and fresh
water.
They make up a large
part of the
phytoplankton.
The cell walls contain
a glasslike substance
called silica.
The cells are enclosed
in a two part shell.
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Dinoflagellates are
single celled.
Most live in salt water,
but a few live in fresh
water and even snow.
They have two whip
like strands called
flagella.
The beating of the
flagella causes the
cells to spin through
the water.
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They are single celled
protists that live in fresh
water
They use their flagella
to move through the
water.
Many are producers
but some become
heterotrophs when
there is not enough
light to make food.
Others do not have
chlorophyll and must
always get food.
Digestion occurs in a food vacuole.
 Oxygen passes through the cell
membrane.
 The food vacuole joins with the cell
membrane to release waste.
 They have an eyespot and respond to
light.

Photosynthesis takes
place in chloroplasts,
which contain
chlorophyll.
 Most euglenoids have
two flagella, short and
long.
 They can’t see but
they have eyespots
sense light.
 A contractile vacuole
holds excess water
and removes it from
the cell.
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Some heterotrophic protists have special
traits that allow them to move and are
known as protozoans.
Those that can move are usually singlecelled consumers or parasites.
Some examples are:
Amoebas
Shelled amoeba-like protists
Zooflagellates
Ciliates
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Amoebas are jellylike
protozoans, found in
both salt and fresh
water, in soil and as
parasites in animals.
They look shapeless
but are highly
structured.
They have vacuoles
to get rid of excess
water.
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Many amoebas eat
bacteria and small
protists, but some are
parasites that get
food by invading
other organisms.
Certain amoebas
live in human
intestines and cause
dysentery which
causes internal
bleeding.
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Amoebas and
amoeba-like protists
move with
pseudopodia, which
means “false feet”.
To move the
amoeba stretches a
pseudopod out from
the cell and then the
cells flows into the
pseudopod.
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Pseudopodias are also
used to catch food.
When it sense a food
source, it moves
toward the food and
surrounds it, forming a
food vacuole.
Enzymes move into the
vacuole to digest the
food and the digested
food passes into the
amoeba.
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Amoebas reverse
the process to get rid
of wastes.
A waste-filled
vacuole is moved to
the edge of the cell
and released.
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Amoeba proteus can
sense light and tends to
move away from it.
Just before it reproduces, it
rounds up into a ball with
tiny pseudopodia
extensions. Over the next
15 minutes or so, it splits
and becomes two. Image
below shows one amoeba
in the final stages of
splitting. Look carefully
and you can see the clear
channel between the two
new amoebas.
Not all amoeba-like
protists look shapeless,
some have an outer
shell.
 Radiolarian shells look
like glass ornaments.
 Foraminiferans have
snail-like shells. They
move by poking
pseudopods out the
pores in the shell.
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Zooflagellates are
protists that wave
flagella back and
forth to move.
Some live in water.
Others live in the
bodies of other
organisms.
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Some zooflagellates
are parasites that
cause disease.
Giardia lamblia can
live in the digestive
tract of many
vertebrates., causing
severe stomach
cramps.
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Some zooflagellates
live in mutualism with
other organisms, each
helping the other live.
The zooflagellate that
lives in the gut of
termites digests the
cell walls of the wood
that termites eat and
in return the termite
gives the protist food
and a place to live.
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Ciliates are complex
protists. They have
hundreds of tiny hairlike structures known
as cilia which they
use for both moving
and feeding.
The best known
ciliate is
Paramecium.
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The cell of a
paramecium has two
kinds of nuclei.
A large nucleus called
a macronucleus
controls the function of
the cell.
A smaller nucleus, the
micronucleus, passes
genes to another
paramecium during
sexual reproduction.
The stentor moves using cilia.
It creates a whirlpools to suck
in food and is sometimes
called the trumpet cell.

It is large enough that it can
sometimes be seen without
the microscope. It forms a ball
in order to look larger.
 Digestion occurs in a food
vacuole.
 Oxygen is diffused or released
through the cell membrane.
Food vacuoles join with the
cell membrane to release
waste.
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When stentors are
traveling, they are
not in the typical
trumpet shape, but
contract into a more
oval shape.
The cilia on the
trumpet bell closes
up, and the cilia on
the body are used
for locomotion.
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Stentors have a
rather complex
reproductive cycle.
Here a stentor
undergoing division.
They use a
micronucelus for
reproduction.
Not all protists heterotrophs can move.
 Some of these protists are parasites that
do not move.
 Others can move only at certain phases
in their life cycle.
 Some examples are:
 Spore-forming Protists
 Water Molds
 Slime Molds
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Many spore-forming
protists are parasites.
They absorb nutrients
from their hosts.
They have no cilia or
flaglella to move.
They have
complicated life
cycles that involve two
hosts like the protist, P.
Vivax that causes
malaria.
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Water molds are also
heterotrophic protists
that can’t move.
Most water molds
are small and singlecelled.
Many live in water,
moist soil or other
organisms, but some
are decomposers
Many are parasites.
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Slime molds are
heterotrophic protists
that can move only
at certain phases of
their life cycle.
They look like thin,
colorful shapeless
globs of slime.
They live in cool
moist places in the
woods.
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Some live as a giant
cell that has many
nuclei and a single
cytoplasm at one
stage of life. As long
as food and water are
available, it will grow.
Others live as single
cells which can come
together when times
are stressful.
When environmental
conditions are stressful
slime molds grow stalklike structures with
rounded knobs at the
top, containing spores.
Spore are small
reproductive cells
covered by a thick cell
wall.
The spores can survive for
a long time without
water or nutrients.

A person who studies fungi.
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Most fungi are
consumers that they
get their nutrients by
secreting digestive
juices on their
surroundings and
absorbing the food.
Many are
decomposers and
others are parasites.
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Some live in
mutualism, called
mycorrhiza, with
other organisms.
Fungi grow on or in
the roots of a plant
which provides
nutrients to fungus.
The fungus helps the
root absorb minerals
and protects the
plant from disease.
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Many celled fungi are
made up of chains of
cells called hyphae.
Hyphae are threadlike
fungal filaments.
These filaments are
made of cells that
have openings in their
cell walls. These
openings allow
cytoplasm to move
freely between cells.
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Most of the hyphae
that make up a
fungus grows
together to form a
twisted mass called
the mycelium .
The mycelium makes
up the major part of
the fungus but most
of it is hidden
underneath the
ground.
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Reproduction may
be sexual or asexual.
Asexual
reproduction occurs
in two ways.
The hyphae may
break apart and
each becomes a
new fungus or spores
are produced and
spread.
Fungi are classified based on their shape
and the way that they reproduce.
 There are four main groups of fungi:
 Threadlike fungi
 Sac fungi
 Club fungi
 Imperfect fungi
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Most threadlike fungi
live in the soil and
are decomposers.
Some threadlike
fungi are parasites.
A black bread mold
is an example of
something that
belongs to this
group.

Threadlike fungi can
reproduce asexually.
Parts of the hyphae
grow into the air and
form spore cases at
the tip, called
sporangia. When
they break open
they are released
into the air.
Threadlike Fungi
reproduce sexually when
a hypha from one
individual joins with a
hypha from another
individual. The hyphae
grow into specialized
sporangia that can
survive times of cold or
little water. When
conditions improve, they
will grow into a new
fungi.
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Sac Fungi area the
largest group of fungi
which includes yeasts,
mildew, They can
reproduce both
sexually and asexually.
When they reproduce
sexually they form a
sac called an ascus.
Spores develop within
the sac.
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Yeasts are singlecelled sac fungi.
When they
reproduce asexually,
they use a process
called budding.
In budding a new
cell pinches off from
an existing cell.
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Yeast are used to
make breads and
alcohols.
Yeasts use sugar as
food and produce
carbon dioxide gas
and alcohol as
waste. Trapped
bubbles of carbon
dioxide cause the
bread to rise.
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Yeast is also used to
make antibiotics
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Some yeasts, such as
truffles and morels,
are prized as human
foods.
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Some sac fungi are
parasites and cause
Dutch elm disease
which is harmful to
the tree.
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The umbrella-shaped
mushrooms are the
most familiar fungi.
The group gets its
name from structures
that the fungi grow
during reproduction.
Club fungi reproduce
sexually by growing
special hyphae that
form clublike
structures.

These clublike
structures are called
basidia from the
Greek word for
clubs. Sexual spores
develop on the
basidia.
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The most familiar
mushrooms are
known as gill fungi.
The basidia of these
mushrooms develop
in structures called
gills, under the
mushroom cap.
Some are sold in
grocery stores, while
others are very
poisionous.
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Mushrooms are not
the only club fungi.
Bracket fungi grow
outward from wood
and from small
shelves.
Smuts and rusts are
plant parasites that
attach corn and
wheat.
The imperfect fungi
group includes all of
the species that do
not fit. They do not
reproduce sexually.
 Most are parasites that
causes diseases in
plants and animals.
 One common human
disease is athlete’s
foot.
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Peniciliium is the
fungi that is the
source of the
antibiotic Penicillin.
Other imperfect
fungi produce some
cheeses, soy sauce
and the citric acid
used in cola drinks.
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A lichen is a
combination of a
fungus and an alga
that grow together.
The alga lives inside
the protective wall
of the fungus.
The merging of the
two is so complete
that scientists give
lichens their own
scientific name.
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Unlike fungi, lichen
are producers.
The algae produces
food through
photosynthesis.
Lichens keep the
algae from drying
out.
Lichens can be
found in almost any
environment.
Because lichens need
only air, light and
minerals to grow, they
can grow on rocks.
 As lichens grow, the
changes they make to
their surroundings
allow other organisms
to live there also.
 They break down the
rock and as they die,
they form soil from the
decaying matter.
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Lichens absorb
water and minerals
from the air.
As a result, they are
easily affected by air
pollution.
The presence or
absence of lichens is
a good indication of
the quality of the
surrounding air.