General Zoology Unit Two

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General Zoology Unit Two
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Protista
Eukaryotic, unicellular organisms
Many have cell walls
Autotrophic or heterotrophic
Intracellular specialization (division of labor)
Simple reflexes
Found wherever life exists
Asexual reproduction and conjugation
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Protist Taxonomy
Kingdom - Protista
Phylum - Chlorophyta Ex. Volvox
Phylum - Retortamonada
Class Diplomonadea Ex. Giardia
Phylum - Axostylata
Class Parabasalea Ex. Trichomonas
Phylum - Euglenozoa
Class Euglenoidea Ex. Euglena
Class Trypanosomatidea Ex. Trypanosoma
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Protist Taxonomy
Phylum - Apicomplexa
Class Coccidea Exs. Plasmodium,
Eimeria, Toxoplasma
Phylum - Ciliophora
Exs. Paramecium, Stentor, Vorticella
Phylum - Dinoflagellata
Exs. Zooxanthella, Ceratium, Noctiluca
Amebas no longer a single taxonomic group
Exs. Amoeba, Difflugia
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Phylum - Chlorophyta
Unicellular multicellular algae
Individual colonial species
Move with flagella
Have chloroplasts, therefore autotrophs
Volvox
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Phylum - Retortamonada
Class - Diplomonadea
Unicellular individuals
No mitochondria or Golgi bodies
Move with several flagella
Many are intestinal parasites, others live in
anoxic conditions
Giardia
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Phylum - Axostylata
Class - Parabasalea
Unicellular individuals
Have Golgi bodies, but no mitochondria
Move with several flagella
Have an axostyle
Trichomonas
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Phylum - Euglenozoa
Class - Euglenoidea
Unicellular individuals
Have a pellicle
Move with a single flagella
Have contractile vacuoles stigma
Autotrophs that can be heterotrophic
Euglena
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Phylum - Euglenozoa
Class - Trypanosomatidea
Unicellular individuals
Have a pellicle
Move with a single flagella
All members are parasitic
Trypanosoma causes sleeping sickness (vector -
tsetse flies)
Trypanosoma
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Phylum - Apicomplexa
Class - Coccidea
Unicellular individuals
All members are parasitic
No structure for locomotion
Have rhoptries
Plasmodium causes malaria (vector Anopholes)
Eimera infects fowl, resulting in coccidiosis
Plasmodium
Toxoplasma infects mammals
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Phylum - Ciliophora
Unicellular individuals
Have a pellicle
Cytoplasm made up of ectoplasm endoplasm
Have two nuclei
Have contractile vacuoles
Have digestive complexity
Have structures for food gathering and protection
Paramecium
Most free living, some parasites
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Ciliophoran Anatomy
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Phylum - Dinoflagellata
Unicellular individuals
Move with two flagella
Some autotrophic, some heterotrophic
Form the producing base for plankton
Form important symbiotic relationships
Noctiluca
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Amebas
Unicellular individuals
Not a monophyletic group
Cytoplasm made up of ectoplasm endoplasm
Asymmetrical
Have contractile vacuoles
Move with pseudopods
Some have tests, others are naked
Amoeba
Most free living, some parasites
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Protist Nutrition
Autotrophs produce their own food
Heterotrophs two types
Phagotrophs (holozoic)
Osmotrophs (saprozoic)
Phagosome a food vacuole
Contractile vacuole water excretion
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Surface area increases in multiples of two (L x W)
Volume increases in multiples of three (L x W x D)
Therefore the volume will increase quicker than
the surface area during cell growth
A high SA/V ratio means a cell can more easily
maintain itself, can grow larger and become more
complex
The danger of a high SA/V ratio is that
substances dangerous to the cell can more easily
get in
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Asexual Reproduction
Asexual reproduction involves only one parent
It has advantages in that it does not require a
mate and the organism can exploit good
environmental conditions
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Asexual Reproduction
These advantages enable the organism to use its
energy resources most effectively on reproduction
The major disadvantage is the lack of genetic
diversity, possibly leading to decreased fitness
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Sexual Reproduction
Sexual reproduction involves two parents
Its primary advantage is the genetic diversity it
produces and the resulting increase in fitness
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Sexual Reproduction
The primary disadvantage of sexual reproduction
is the inefficient use of energy in seeking and
competing for mates
This strategy many times does not allow for the
best exploitation of ecological resources
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Binary fission
asexual reproduction
one individual splits into two
cell division due to low SA/V ratio
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Schizogony
asexual reproduction
one individual splits into many
Plasmodium carries out schizogony
Budding
asexual reproduction
a tiny cell grows (buds) from the side of the
parent
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Conjugation
a process in which genes are recombined
two individuals exchange genetic material
no new individuals produced, but two are
changed genetically
a
a
a
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Autogamy
asexual process
similar to conjugation
individual self fertilizes
Syngamy
a sexual process
fertilization of a gamete by another
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Trichomonas Vaginitis
Trypanosoma Sleeping sickness
Plasmodium Malaria
Amoeba Dysentery
Giardia Beaver fever
Balantidium Colon perforations
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Definitions
Metazoans multicellular animals
Cell aggregates metazoans with no tissues
Eumetazoans metazoans with tissues
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Three Hypotheses for the Evolution of Metazoans
Syncytical Ciliate Hypothesis metazoans
originated from ciliates
Colonial Flagellate Hypothesis metazoans
originated from colonial flagellates
Polyphyletic Origin Hypothesis metazoans
originated from several sources
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Porifera
Eukaryotic, metazoans
Cell aggregates
No true tissues or organs
All aquatic, most marine
Asymmetrical
Body covered in pores
Made up of several types of independent cells
Skeleton of spicules, spongin and collagen
All are sessile
Asexual and sexual reproduction
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Poriferan Taxonomy
Kingdom - Animalia
Phylum - Porifera
Class Calcarea (calcium carbonate spicules)
Ex. - Sycon
Class Hexactinellida (silicon based spicules)
Ex. - Euplectella
Class Demospongiae (spongin)
Ex. Spongilla, Cliona
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Mesohyl
Archaeocytes differentiate into other cells that
produce the sponge skeleton (spicules, collagen
and spongin)
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Sponge Body Forms
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Filter feeding organisms
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Class - Calcarea
Have calcium carbonate spicules
All asconoid forms are in this class
Some syconoid forms are in this class
Most members of this class is of the leuconoid
form
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Class - Hexactinellida
Have silicon based spicules
Sometimes referred to as glass sponges
All are deep sea forms
Some members are of the syconoid form while
others have the leuconoid form
Euplectella
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Class - Demospongiae
Skeleton mainly spongin, with silicon spicules in
some
95 of all extant sponges are in this class
All members of this class are of the leuconoid
form
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Definitions
Monoecious (one house) both sexes in one
individual (hermaphroditic)
Dioecious (two house) - separate sexes housed in
different individuals
Gemmules internal buds formed during adverse
conditions
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Sponge Reproduction
Most sponges are monoecious
Asexual reproduction budding (external buds),
gemmules and fragmentation
Sexual reproduction sperm released from
individuals and eggs retained
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Definitions
Diploblastic having two germ layers from which
tissues and structures arise
Ectoderm outer germ layer that gives rise to
tissues and structures that cover the outside
Endoderm inner germ layer that gives rise to
tissues and structures that cover the inside
Mesoglea jelly-like substance found between the
inner and outer layers
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Blastula
Gastrula
Diploblastic
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Cnidaria
Eukaryotic, eumetazoans
Diploblastic
Have true tissues, but no organs
All are marine
Radially symmetrical (no cephalization)
Polymorphic two forms (polyp medusa)
Cnidocytes stinging cells
Have a nerve net
Polyps are sessile, while medusae can move
Asexual and sexual reproduction
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Cnidarian Taxonomy
Kingdom - Animalia
Phylum - Cnidaria
Class Hydrozoa
Ex. Physalia, Obelia, Hydra, Gonionemus
Class Scyphozoa (true jellyfish)
Ex. Aurelia, Cassiopeia
Class Cubozoa
Ex. Carybdea
Class Anthozoa
Ex. Metridium, Gorgonia, Tubipora
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Cnidarian Polymorphism
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Polyp Anatomy
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Gonionemus
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Aurelia
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Cnidocyte Anatomy
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Class - Hydrozoa
Most are marine and colonial in form
Most forms exhibit alternation of generations
between asexual polyps and sexual medusae, but
some have only one or the other form
Hydra
Obelia
Physalia
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Class - Scyphozoa
Referred to a the true jellyfish
All are solitary
Polyp stage is much reduced or absent
Main body is cup shaped
Aurelia
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Class - Cubozoa
Most are relatively small in size
All are solitary
Polyp stage is much reduced
Main body is cube shaped
Carybdea
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Class - Anthozoa
Polyp form predominant, no medusa stage
Some are solitary, while others are colonial
Many form zooxanthellae relationship with algae
Most ecologically important group due to reef
building
Metridium
Gorgonia
Tubipora
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Alternation of generations
Planula
Budding
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Alternation of generations
Planula
Budding
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Ctenophora
Eukaryotic, eumetazoans
Diploblastic
Have true tissues, but no organs
All are marine
Biradially symmetrical (no cephalization)
Rows of comb plates
Tentacles with colloblasts
Have a nerve net
Exhibit bioluminescence
Sexual reproduction
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Ctenophore Taxonomy
Kingdom - Animalia
Phylum - Ctenophora
Class Tentaculata
Ex. Pleurobrachia, Cestum,
Coeloplana, Mnemiopsis
Class Nuda
Ex. Beroe
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Ctenophore Diversity
Cestum
Mnemiopsis
Pleurobrachia
Beroe
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Ctenophore Anatomy