Transcript Noncoelomate Invertebrates Power Point

Friday, March 2nd
Noncoelomate Invertebrates
Porifera
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Sponges
Most ancient lineage
Sessile (non-moving)
Lack true tissues or body symmetry
No True Tissues, But Cell Types
• If a sponge is put through a fine sieve or
coarse cloth so the cells are separated, they
will seek one another out and REASSEMBLE
the ENTIRE sponge!
Sexual or Asexual Reproduction
• Asexual: some sponges can break a piece off,
and that piece will grow into a new sponge
• Sexual: sperm is created and released, water
carries it to a sponge of same species.
Captured by new sponge, carried to an egg
cell
• Some sponges allow zygote to grow inside
sponge cavity,
• Other sponges release fertilized egg to
develop elsewhere
Cnidaria
• Jellyfish, Coral, sea
anemones
• True Tissues
• Radial Symmetry
• Have cnidocytes (stinging cells on
tentacles)
Cnidarians Body Plans
• Polyp: cylindrical body, with mouth
surrounded by tentacles – usually attached to
something solid (reef or rocks), but if it is a
colony, they can all be attached to common
tissue
• Medusa: umbrella-shaped, mouth on
underside surrounded by tentacles, live free in
the water
• Some can alternate between the two in their
reproductive cycle
Platyhelminthes
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Flatworms (tapeworms) and flukes
True tissue
Bilateral Symmetry
Lack internal cavity
Digestion in Platyhelminthes
• No circulatory system – Oxygen and Food
diffuse between its cells (body is very thin!)
• Its gut digests and transports, branches of gut
extend throughout the body
Flatworm Reproduction
• Most are hermaphroditic - each individual
contains both male and female sexual
structure
• Copulation between two individuals results in
each partner depositing sperm into the other
• Freshwater flatworms: eggs produce miniadults
• Marine flatworms: egg results in larva, floats
around, metamorphoses into adult form
Flatworms Cont
• Can be Free-Living
• Or Parasitic (includes flukes)
Parasitic Fluke
Nematoda
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A.K.A. Aschelminthes
Round worms (hookworms and pinworms)
True Tissues
Bilateral Symmetry
Protostome Development
Pseudocoelom
Nematoda Fun Facts
• A large handful of fertile soil may contain, on
average, a million nematodes
• Largest known nematode can grow up to 9
meters in length! (it attacks the placenta of
sperm whales)
• Infection by Wucherreria bancrofti may result
in elephantiasis (worms clog the lymph nodes,
resulting in swelling)
Which of the following organelles
modifies and packages for secretion
the materials produced by the
ribosomes?
(A) The Chloroplast
(B) The Golgi Apparatus
(C) The Nucleus
(D) The Nucleolus
(E) The Mitochondria
A student using a light microscope
observes a cell and correctly decides
that it is a plant cell because
(A) Ribosomes are visible
(B) An endoplasmic reticulum can be seen
(C) A cell membrane is present
(D) It has a large central vacuole
(E) centrioles are present
The condition in which there are
barriers to successful interbreeding
between individuals of different
species in the same community is
referred to as
(A) Latent Variations
(B) Sterility
(C) Structural Differences
(D) Geographic Isolation
(E) Reproductive Isolation
In sheep, eye color is controlled by a single gene with 2
alleles. When a homozygous brown-eyed sheep is crossed
with a homozygous green-eyed sheep, blue-eyed
offspring are produced. If the blue-eyed sheep are mated
with each other, what percent of their offspring will most
likely have brown eyes?
(A) 0%
(B) 25%
(C) 50%
(D) 75%
(E) 100%
Which of the following occurs
during mitosis but not during
meiosis I?
(A) The chromosomes are pulled to opposite
poles of the spindle apparatus
(B) The chromatids of each chromosome are
separated
(C) The nuclear envelope breaks down
(D) Both synapsis and crossing-over take place
(E) The diploid number of chromosomes is
reduced to the haploid number
Membranes are composed of all of the
following EXCEPT a
(A) Microtubule
(B) Nucleus
(C) Golgi Apparatus
(D) Mitochondrion
(E) Lysosome
Which of the following statements best expresses the
concept of punctuated equilibrium?
(A) Small variations gradually accumulate in evolving
lineages over periods of millions of yrs
(B) Random mating ensures that the proportions of
genotypes in a population remain unchanged from
generation to generation.
(C) Stability is achieved when selection favors the
heterozygote, while both homozygotes are at a
disadvantage
(D) Evolutionary changes consist of rapid bursts of
speciation alternating with long periods in which
species remain essentially unmodified
(E) Under competition for identical resources, one of the
two competing species will be eliminated or excluded.
The gametophyte is the dominant
generation in which of the following
plants?
(A) Dicots
(B) Monocots
(C) Gymnosperms
(D) Ferns
(E) Mosses
In plants, the initiation of flowering in
response to photoperiod is triggered
by changes in:
(A)Ethylene
(B) Auxin
(C) Giberellic Acid
(D)Photochrome
(E) Cytokinin
In humans, red-green color blindness
is a sex-linked recessive trait. If a man
and woman produce a color-blind son,
which of the following must be true?
(A) The father is color-blind
(B) Both parents carry the allele for color blindness
(C) Neither parent carries the allele for color
blindness
(D) The father carries the allele for color blindness
(E) The mother carries the allele for color blindness
Which of the following is the most
likely explanation for a high rate of
crossing-over between two genes?
(A) The two genes are far apart on the same
chromosome
(B) The two genes are both located near the
centromere
(C) The two genes are sex-linked
(D) The two genes code for the same protein
(E) The two genes are on different chromosomes.