Food for Thought

1
Food for Thought
Interest Grabber
Section 20-1

• What do you do when you get hungry? You probably
  go in search of food. Different organisms have
  different ways of obtaining the nutrients they
  need to live.

1. How does an animal obtain food? 2. How does a
plant obtain food? 3. Predict how a
microorganism described as plantlike might
behave.
2
Section Outline
Section 20-1

• 201 The Kingdom Protista
• A. What Is a Protist?
• B. Evolution of Protists
• C. Classification of Protists

3
Concept Map
Section 20-1
Protists
are classified by
which include
which
which
which
4
(No Transcript)
5
What are Protists?

• Protists are eukaryotes that are not members of
  the kingdom Plantae, Animalia, Fungi.
• Most are unicellular. (Some are multicelluar,
  while some unicellular organisms live in
  colonies.)
• May be heterotrophic or autotrophic
• Most live in an aquatic environment.
• Most are mobile.

http//protist.i.hosei.ac.jp/GIFs/protists.jpg
6
Evolutionary Standpoint

• Evolutionary Protists are a connective kingdom
  because they are unicelluar and also contain
  membraned organelles.
• Lynn Margulis suggested that the first eukaryotes
  evolved from a symbiotic relationship between
  several cells.
• Chloroplasts and mitochondria arose out of
  photosynthetic and aerobic prokaryotes living on
  other cells.

http//www.anisn.it/scienza/evoluzione2005/marguli
s.htm
7
Endosymbiotic Theory

• The endosymbiotic theory states that some
  eukaryotic organelles evolved from prokaryotes.
  For example, the mitochondrion and chloroplast
  originated as prokaryotic cells that came to
  reside within a host cell. They enabled the host
  cell to use sunlight as an energy source (the
  chloroplast) and use aerobic cellular respiration
  (the mitochondrion). In return, the host cell
  provided the necessary nutrients, a stable
  chemical environment, and protection.

http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files/Bio20102/Bio2010220lectures/Proti
sts/protists.htm
8
On the Move
Interest Grabber
Section 20-2

• Think about the last time you watched a puppy at
  play, a fish in an aquarium, or a squirrel in the
  park. They dont stay still for long. How do they
  get where they are going?

1. List five different ways in which animals can
move from place to place. 2. What structures do
these animals have that enable them to
move? 3. What structures might a microorganism
need in order to move?
9
Section Outline
Section 20-2

• 202 Animallike Protists Protozoans
• A. Zooflagellates
• B. Sarcodines
• C. Ciliates
• 1. Internal Anatomy
• 2. Conjugation
• D. Sporozoans
• E. Animallike Protists and Disease
• 1. Malaria
• 2. Other Protistan Diseases
• F. Ecology of Animallike Protists

Disk 4 Protist Video
10
Classification

• Zooflagellates
• Phylum Zoomastigina
• Animal like protists (Heterotrophs)
• They absorb their food through their cell
  membranes.
• Decaying matter in streams and lakes.
• Like with in bodies of living organisms
• Swim using flagellum (One or two)
• Flagellum are a whip-like tail
• Most reproduce asexually through mitosis and
  cytokinesis.
• Others reproduce sexually. Gametes are formed
  through meiosis.

http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files /Bio20102/Bio2010220Laboratory/Pr
otists/protists.htm
http//www.sirinet.net/jgjohnso/protista.html
11
Sarcodines

• Phylum Sarcodina
• Animal like protists (Heterotrophic)
• Use pseudopods for movement and feeding.
  (Pseudopods are cytoplasmic projections that
  extend away from the body.)
• Amoebiod movement is caused when the pseudopod
  extends out and the cytoplasm streams into the
  pseudopod causing the rest of the cell to move.
• Food vacuole is a small cavity in the cytoplasm
  that temporarily stores food.
• Reproduce through mitosis and cytokinesis.
• Foraminiferans formed the white chalk cliffs of
  Dover.
• Heliozoans sun animal

http//www.radil.missouri.edu/info/para/protozoa/
http//www.sirinet.net/jgjohnso/foraminiferans.jp
g
http//www.olympusmicro.com/primer/techniques/dic/
dicgallery/images/actinosphaeriumlarge.jpg
12
Figure 20-4 An Amoeba
Section 20-2
13
Ciliates
http//ic.ucsc.edu/wxcheng/envs161/Lecture8/cilia
te.jpg

• Phylum Ciliophora
• Cilia are short hairlike projections.
• Animal like (Heterotrophs)
• Use cilia for movement and feeding.
• Found in both fresh and salt water environments.
• Reproduce asexually by mitosis and cytokinesis.
• Conjugation is a process in which genetic
  material is exchanged between two individuals.

http//www.microscopy-uk.org.uk/mag/indexmag.html?
http //www.microscopy-uk.org.uk/mag/wimsmall/cili
dr.html
Trichocysts of a Paramecium
14
Figure 20-5 A Ciliate
Section 20-2
Bottle shaped structures used for protection.
Indentation located on one side of the organism.
Food particles are swept into the oral groove and
gullet where they form a food vacuole
Region where waste material is discharged into
the environment
Cavities in the cytoplasm that are specialized to
collect and discharge water to maintain
homeostasis.
Reserve copy of the cells genes.
Site of genes used in daily processes.
15
Conjugation

• Two sexually compatible individuals join at an
  oral groove.
• First meiotic division in each cell of
  micronuclei.
• Second meiotic division in each cell and
  macronuclei disintegrate.
• One haploid nucleus divides by mitosis the
  other disintegrates.
• Each conjugating cell exchanges a micronucleus.
• Haploid micronucleus fuse.
• Cells separate with a diploid nucleus.

Spirostomum conjugating
http//www.microscopy-uk.org.uk/mag/indexmag.html?
http//www.microscopy-uk.org.uk/mag/wimsmall/cilid
r.html
16
Conjugation
Section 20-2
New macronucleiform
Macronucleus
Micronucleus
MEIOSIS
Exchange ofmicronuclei
Macronucleidisintegrate
Genetically identical paramecium form
17
Sporozoans

• Phylum Sporozoa (Apicomplexa)
• Animal like (Parasitic)
• Do not move on their own
• Most have a complex life cycle
• Reproduce by sporozoites.
• Malaria is caused by a sporozoans.

http//home.austarnet.com.au/wormman/wlimages.htm
18
Figure 20-7 The Life Cycle of Plasmodium
Section 20-2
19
Other Protistan Diseases
http//www.microbiotest.com/affiliations.htm

• Trypanosoma African sleeping sickness.
• Spread by tsetse fly
• Can cause deep, possibly fatal sleep.
• Entamoeba parasite spread by contaminated
  drinking water and causes excessive bleeding.
• Giardia causes sever diarrhea and digestive
  problems.

medschool.sums.ac.ir
http//www.nih.go.jp/niid/para/atlas/images/giardi
a-trph.jpg
http//www.uiowa.edu/cemrf/archive/sem/large/Giar
dia.gif
20
Ecology of Animallike Protists

• Animal like protists play an essential role in
  the living world.
• Used as a food source in aquatic organisms.
• Trichonympha live in the digestive track of
  termites. These protists produce an enzyme
  called cellulase, which breaks down cellulose.

21
Whats in a Name?
Interest Grabber
Section 20-3

• Pyrrophyta and Chrysophyta are two common phyla
  of protists. Notice that these names begin with
  the prefixes pyrro- and chryso-, which are
  derived from Latin words. The root, -phyta, is
  also derived from a Latin word.

22
Interest Grabber continued
Section 20-3

• 1. Using a dictionary, look up the prefixes
  pyrro- and chryso-, as well as the root -phyta.
  What do these terms mean?
• 2. Use the information you found in the
  dictionary to find out the meaning of Pyrrophyta
  and Chrysophyta.
• 3. Based on the meaning of their names, what
  characteristics might the protists in each of
  these phyla have?

23
Section Outline
Section 20-3

• 203 Plantlike Protists Unicellular Algae
• A. Chlorophyll and Accessory Pigments
• B. Euglenophytes
• C. Chrysophytes
• D. Diatoms
• E. Dinoflagellates
• F. Ecology of Unicellular Algae
• Algal Blooms

24
Plantlike Protists

• Chlorophyll and accessory pigments are used to
  classify the different protists.
• Chlorophyll A
• Chlorophyll B
• Chlorophyll C
• Other pigments absorb light at different
  wavelengths than chlorophyll. (Give algae a wide
  range of colors.)

http//encarta.msn.com/media_461516565/Green_Algae
.html
25
Euglenophytes
http//www.bio.mtu.edu/the_wall/phycodisc/EUGLENOP
HYTA/

• Phylum Euglenophyta
• Plantlike protists
• Two flagellum
• Motile with use of the flagellum
• Contain chloroplasts
• Eyespot is a reddish pigment used to locate
  sunlight to power photosynthesis.
• Do not have a cell wall. Rather they contain a
  pellicle, which is an intricate cell membrane.
• Reproduce asexually

26
Euglena
Section 20-3
Chloroplast
Carbohydrate storage bodies
Gullet
Pellicle
Contractile vacuole
Nucleus
Eyespot
Flagella
27
Chrysophytes

• Phylum Chrysophyta
• Golden-brown and yellow-green algae
• Plantlike protist
• Contain chlorophyll and fucoxanthin a bright
  yellow golden pigments.
• Reproduce either sexually or asexually.
• Cell wall is made of pectin rather than
  cellulose.

http//www.microscopy-uk.org.uk/mag/indexmag.html?
http//www.microscopy-uk.org.uk/mag/wimsmall/flagd
r.html
28
Diatoms
http//scitec.uwichill.edu.bb/bcs/bl14apl/algae1.h
tm

• Phylum Bacillariophyta
• Extremely abundant
• Produce thin, delicate cell walls rich in
  silicon.
• Cell walls are arranged like a petri dish.
• Live in water.
• When die, they slowly sink to the bottom of the
  ocean, forming thick layers that can be mined at
  a later date.

Award winning picture of a marine diatom by Wim
van Egmond
http//www.cssd11.k12.co.us/dohnts/Biology/bio05nt
.htm
29
Dinoflagellates
http//www.geo.ucalgary.ca/macrae/palynology/dino
flagellates/Ceratium_zoom.gif

• Phylum Pyrrophyta
• ½ are heterotrophic
• ½ are autotrophic (photosynthetic)
• 2 flagellum (one wraps around the organism,
  similar to a belt.
• Reproduce through binary fission
• Cell wall made of cellulose
• Many are bioluminescent (create light)
• Pyrrophyta

http//www.nhm.ac.uk/research-curation/projects/al
gaevision/database/detail.jsp?taxonimageID2089
GenusNameCeratiumSpeciesNamefurcoides
30
Ecology of Unicellular Algae

• Found in both fresh and salt waters
• Large part of the marine ecosystem
• Phytoplankton are found near the surface of the
  ocean and carry out half of the photosynthesis on
  Earth and larger organisms feed off them.
• Negative
• Algal blooms form when the conditions are right
  for the rapid growth of protists due to an
  increase in pollution.
• They can rod the water of oxygen and/or release
  toxins in the water or other organisms.
• Red Tide caused by Karenia brevis
• Shell fish can become toxic due to an increase in
  protist concentration.

31
Sargasso Sea Story
Interest Grabber
Section 20-4

• Many square kilometers of the open Atlantic Ocean
  between the islands of the Azores and the Bahamas
  are covered by huge, floating protists called
  Sargassum. Known as the Sargasso Sea, this area
  of warm water is named for the brown protists
  that dominate its surface.

1. Why do you think Sargassum and other similar
protists are called seaweeds? 2. Compare and
contrast Sargassum to another type of brown algae
you have read about in this chapter. How are they
different?
32
Section Outline
Section 20-4

• 204 Plantlike Protists Red, Brown, and Green
  Algae
• A. Red Algae
• B. Brown Algae
• C. Green Algae
• 1. Unicellular Green Algae
• 2. Colonial Green Algae
• 3. Multicellular Green Algae
• D. Reproduction in Green Algae
• 1. Reproduction in Chlamydomonas
• 2. Reproduction in Ulva
• E. Human Uses of Algae

33
Red Algae

• Phylum Rhodophyta
• Able to live at great depths
• Contain chlorophyll a and phycobilins (reddish
  pigment)
• Absorb blue light (Ocean water absorbs red and
  violet light)
• Most are multicellular
• Lack flagellum
• Aid in coral reef development

http//www.splashdowndivers.com/reefs/red_algae/
34
Brown Algae
http//www.pbs.org/oceanrealm/seadwellers/cathedra
ldwellers/kelp.jpg

• Phylum Phaeophyta
• Contains chlorophyll a and c as well as
  fucixanthin, a brown pigment.
• Largest and most complex of the algae.
• Giant kelp (60 meters in length)
• Sargassum
• All multicellular.

35
Anatomy of a Brown Algae
36
Green Algae
Green Algae

• Phylum Chlorophyta
• Contain chlorophyll a and b
• Cell walls made of cellulose
• Store food as starches
• Possible ancestor of land plants through a common
  ancestor
• Many are unicellular
• Some are colonial but show few specialized
  structures.
• Few are multicellular
• Alteration of generations many algae switch
  back and forth between haploid and diploid
  stages.

• Unicellular Chlamydomanas
• Found in ponds, ditches and wet soil
• Two flagella, single chloroplast and two small
  contractile vacuoles.
• Colonial Spirogyra / Volvox
• -May consist of a few cells (500) to many cells
  (50,000).
• -Many share cytoplasm
• Multicellular Ulva
• -several specialized cell types

37
Reproduction in Chlamydomonas

• UNFAVORABLE CONDITIONS
• Sexual
• Goes through mitosis producing gametes instead of
  zoospores.
• Opposite mating types ( and -)
• 3. Gametes group, pair up and move away from the
  group.
• The two gametes join flagella and spin
• Shed cell walls and fuse becoming diploid
• Forms thick protective wall around the zygote,
  which can survive extreme conditions.
• When conditions are favorable again the zygote
  goes through meiosis to form four flagellated
  haploid cells.

• Single celled and spends most of its life in the
  haploid stage.
• FAVORABLE CONDITIONS
• 1. Asexual
• 2. Through mitosis, produces 2 haploid zoospores

38
Figure 20-17 The Life Cycle of Chlamydomonas
Section 20-4
Zoospores
Release of haploid cells
MEIOSIS
Zygote
Mature cell
Pairing of plus and minus gametes
MITOSIS
MITOSIS
Haploid Diploid
39
Reproduction in Ulva

• Haploid Phase
• -Gametophytes gamete producing plants
• Ulva produces two forms of gametes (??)
• ?? gametes fuse producing a diploid cell, which
  grows into a large, diploid multicellular Ulva.

• Diploid Phase
• - Sporophyte the diploid Ulva
• The diploid Ulva undergoes meiosis to produce
  haploid reproductive cells called spores.
• Each spore is able to grow into a new individual
  without fusing with another cell.

40
Ulva Life Cycle
Section 20-4
MITOSIS
MEIOSIS
Zygote
Gametes fuse
Sporophyte
Spores
FERTILIZATION
Gametes
Female gametophyte
MITOSIS
Diploid Haploid
Male gametophyte
41
Human Uses of Algae

• Algae produce a large amount of oxygen
• Algae serve as a food source for many aquatic
  organisms.
• Used in medicines
• High blood pressure, arthritis, and stomach
  ulcers
• Nori to wrap sushi
• Make plastics, waxes, deodorants, paints,
  lubricants, etc.
• Thickener in ice cream and agar.

42
A Protist Problem
Interest Grabber
Section 20-5

• Some protists can harm living things by causing
  diseases. Imagine that you live on an island
  where the main source of food for the inhabitants
  is a single type of plant. Protists have caused
  the majority of the crop of that plant to become
  diseased and inedible.

43
Interest Grabber continued
Section 20-5

• Predict the effect the disease will likely have
  on the following
• 1. food supply
• 2. lives of the inhabitants
• 3. island ecosystem
• 4. island economy

44
Section Outline
Section 20-5

• 205 Funguslike Protists
• A. Slime Molds
• 1. Cellular Slime Molds
• 2. Acellular Slime Molds
• B. Water Molds
• C. Ecology of Funguslike Protists
• D. Water Molds and the Potato Famine

45
Funguslike Protists

• Slime Mold
• Heterotrophic protists that absorb nutrients from
  dead or decaying organic matter.
• Cellular slime molds
• Phylum Acrasiomycota
• Spend most of their lives as free-living cells,
  similar to amoebas.
• Reproduce rapidly when nutrients are available
  and produce spores when the conditions are not
  adaptive.
• Send out chemical signals that attract cells of
  the same species.
• Thousand of cells aggregate in the same area into
  a large sluglike colony, functioning together.
• The colony migrates and produces a fruiting body
  (a slender reproductive structure that produces
  spores.

• The spores are scattered from the fruiting body.
• Each spore gives rise to amoeba-like cell that

Click pic for video
http//www.genome.gov/?CFID5834599CFTOKEN433392
41
46
Figure 20-22 The Life Cycle of a Cellular Slime
Mold
Section 20-5
Fruiting body
Emerging amoebas
MEIOSIS
Spores
Aggregated amoebas
Zygote
FERTILIZATION
Haploid (N) Diploid (2N)
Migrating colony
47
Slime Molds Continued

• Acellular Slime Molds
• Phylum Myxomycota
• Begin their life cycle as amoeba-like cells.
• When they aggregate, their cells fuse to produce
  structures with many nuclei called plasmodia.
• A plasmodium is a diploid structure.
• It can form a sporangium that produces haploid
  spores by meiosis.
• The spores scatter and germinate into amoeba-like
  flagellated cells.
• The cells fuse producing a diploid zygote that
  repeats the cycle.

http//nsm1.utdallas.edu/bio/miller/Lab/miller_lab
.html
48
Figure 20-23 The Life Cycle of an Acellular Slime
Mold
Section 20-5
MEIOSIS
FERTILIZATION
Zygote
Germinating spore
Spores
Mature sporangium
Feeding plasmodium
Young sporangium
Mature plasmodium
Haploid (N) Diploid (2N)
49
Water Molds (Oomycetes)

• Phylum Oomycota
• Thrive on dead or decaying matter and some are
  plant parasites.
• Produce hyphae (multinucleated, continuous mass
  enclosed by one cell wall.)
• Cell walls made of cellulose
• Reproduction both sexual and asexual
• Asexual
• Portions of the hyphae develop into zoosporangia,
  which are spore cases.
• Each zoosporangium produces flagellated spores
  that swim in search of food.
• When food is found, they develop into hyphae,
  which grows into a new organism.

• Sexual
• -Hyphae form specialized structures.
• -Antheridium produce male nuclei.
• -Oogonium produce female nuclei.
• -Fertilization, or sexual fusion, occurs within
  the oogonium and the spores that form develop
  into new organisms.

http//www.ou.edu/class/pheidole/pr_oomycota.jpg
50
The Life Cycle of a Water Mold
Section 20-5
51
Ecology and Funguslike Protists

• Recyclers of organic materials.
• Mildew
• Blights of grapes, tomatoes and potatoes.

http//www.news.cornell.edu/releases/March00/Russi
aBlight.bpf.html
http//www.mbbnet.umn.edu/doric/potato.html
52
Video
Video
Algae

• Click the image to play the video segment.

53
Internet
Go Online

• Links on funguslike protists
• Interactive test
• Articles on protists
• Articles on protozoans
• For links on protists, go to www.SciLinks.org and
  enter the Web Code as follows cbn-6201.
• For links on algae, go to www.SciLinks.org and
  enter the Web Codeas follows cbn-6204.

54
Section 1 Answers
Interest Grabber Answers
1. How does an animal obtain food? An animal
obtains food by eating plants or other
animals. 2. How does a plant obtain food? A
plant obtains food by the process of
photosynthesis. 3. Predict how a microorganism
described as plantlike might behave. If the
microorganism is plantlike, then it may obtain
its food by the process of photosynthesis.
55
Section 2 Answers
Interest Grabber Answers
1. List five different ways in which animals can
move from place to place. Possible answers
walking or crawling, flying, swimming, burrowing
2. What structures do these animals have that
enable them to move? Legs, feet, arms, wings,
fins, to name a few 3. What structures might a
microorganism need in order to move? Students
may suggest that microorganisms need structures
similar to that of arms, legs, or fins.
56
Section 3 Answers
Interest Grabber Answers

• 1. Using a dictionary, look up the prefixes
  pyrro- and chryso-, as well as the root -phyta.
  What do these terms mean?
• Pyrro (or pyr) means fire or heat chryso
  means golden -phyta (or phyton) means
  plant.
• 2. Use the information you found in the
  dictionary to find out the meaning of Pyrrophyta
  and Chrysophyta.
• Pyrrophyta means fire plant and Chrysophyta
  means golden plant.
• 3. Based on the meaning of their names, what
  characteristics might the protists in each of
  these phyla have?
• Possible answers Because they are plants, both
  types of protists would perform photosynthesis.
  Protists in the phylum Pyrrophyta give off light,
  and those in the phylum Chrysophyta may be golden
  in color.

57
Section 4 Answers
Interest Grabber Answers
1. Why do you think Sargassum and other similar
protists are called seaweeds? Students may say
that these protists look like large weeds that
grow in the sea. 2. Compare and contrast
Sargassum to another type of brown algae you have
read about in this chapter. How are they
different? Students will likely know that some
algae are multicellular, but most of the algae
they have read about so far are unicellular.
58
Section 5 Answers
Interest Grabber Answers

• Predict the effect the disease will likely have
  on the following
• 1. food supply
• The food supply will be reduced.
• 2. lives of the inhabitants
• With their food supply reduced, inhabitants may
  go hungry, become ill, or die. Some may have to
  leave the island to find food.
• 3. island ecosystem
• The island ecosystem will change because animals
  that depend on the diseased plant for food or
  shelter will also be affected, as will organisms
  that depend on them.
• 4. island economy
• The island economy could be threatened, because
  people may die, leave, or lose a crop that they
  rely on to make money.

59
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