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EXAM 2 REVIEW - ANSWERS
1. Animals and fungi are heterotrophic and have eukaryotic cells.
2. Fungi acquire nutrition through absorption, while animals acquire nutrition through
ingestion.
3. Fungi are heterotrophs that have diverse lifestyles. The three lifestyles are symbiotic
relationships, decomposition, and parasitism. Which type of lifestyle do mychorrizae
represent? Symbiotic relationship
4. Both fungi and arthropods have cell walls made of chitin.
5. Fungi are composed of long, thin filaments known as hyphae that make up the mycelium
of each plant. This should have a large surface area in order to increase absorption rate.
6. Some fungi have cell walls in their hyphae that are called septa. Not having these means
they are aseptate, consist of one cell(s) and have many nuclei.
7. A specialized form of hyphae that can be parasitic or mutualistic is called haustoria.
8. When two mycelia (positive and negative) join together to reproduce sexually, their
cytoplasm mixes together, a process called plasmogamy. The process that happens
afterward when their nuclei fuse is called karyogamy.
9. What does it mean to be dikaryotic? Which types of organisms can be dikaryotic?
Dikaryotic (di=two, kary=nucleus) means a cell has two nuclei that haven’t fused yet.
Fungi have this.
10. Name the three differences between oomycetes (a protist) and fungi. Oomycetes have a
diploid dominant ploidy, cell walls made of cellulose and flagellated cells. Fungi have a
haploid dominant ploidy, cell walls made of chitin and no flagellated cells.
11. The dominant stage of fungi is haploid ploidy; for animals, diploid.
12. What is the product of sexual reproduction? How does asexual differ? When does
meiosis occur? The product of sexual reproduction is a zygote. Asexual reproduction
differs in that all offspring are identical to the parent and there is no zygote involved.
Meiosis occurs in the making of spores.
13. True or False: Fungi have gametes like animals do. False
14. True or False: “Imperfect fungi” have no known sexual reproductive stages. True
15. Why are spores useful to fungi? They are good methods of dispersal.
16. Zygomycota, a phyla of fungi, produces a zygosporangium. What is its main purpose? To
protect the zygote until conditions are favorable.
17. Ascomycota, a phyla of fungi, produces a sac called a(n) ascus in which it produces
ascospores.
18. What are the four important impacts that fungi have on ecosystems and humans?
Decomposers, symbiotic relationships with plants AND animals, human uses and
pathogens (on plants AND animals).
19. Draw a diagram of the early embryonic development. Include the following: blastula,
cleavage, gastrula, gastrulation, blastopore. What happens in each step? Zygote –
Cleavage Blastula –Gastrulation Gastrula with blastopore. During cleavage mitosis
(replication of cells) occurs. During gastrulation the embryo forms germ layers and the
blastopore.
20. What are the three germ layers? Which one is the outside? Inside? Middle? Endoderm
(inside), mesoderm (middle) and ectoderm (outside).
21. What are the four parts of animal’s body plan? Symmetry, embryonic development,
organization of tissues and type of body cavity.
22. What phylum is radially symmetric and diploblastic? Cnidaria
23. What is the difference between radial symmetry and bilateral symmetry? Diploblastic and
triploblastic? Deuterostome and protostome? Radially symmetric organisms can be sliced
any way and have symmetric pieces. Bilaterally symmetric organisms can only be sliced
one way to have 2 symmetric pieces. Diploblastic means 2 germ layers, triploblastic
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means 3. Deuterostomes develop the anus from the blastopore, and protostomes develop
the mouth.
What are the three possible coeloms? Describe them. What characteristic does an animal
have to have a body cavity? What is the importance of a body cavity? Acoelomates,
which have no coelom (filled with mesoderm); pseudocoelomates, which have a body
cavity partially lined with mesoderm; and coelomates, which have a body cavity
completely lined with mesoderm. An animal must be triploblastic to have a body cavity.
A body cavity is important for the protection of organs, provides space for the growth of
organs and acts like a skeleton for some animals.
True or False: There has been one giant cycle of diversification and extinction throughout
time. False
Porifera: Name its symmetry, whether or not is has true tissues, what the purpose of
choanocytes are. True or False: Porifera organisms have perforated bodies.
Asymmetrical; no true tissues; choanocytes are for feeding purposes; true.
Cnidaria: Name its symmetry, whether or not is has true tissues, what the purpose of
cnidocytes are, tissue organization. True or False: Cnidarians have a gastrovascular
cavity. Radial symmetry; has true tissues; cnidocytes are for feeding; diploblastic; true.
Polyp is the sessile form of Cnidarians, while medusa is the mobile form.
Corals do what two important functions? What phylum do corals belong to? Corals, a
part of the Cnidarians, provide environments for other organisms and break tidal waves
for islands.
Lophotrochozoans: Name its symmetry, tissue organization, embryonic development, 3
phyla within this group. True or False: Lophotrochozoans begin to show cephalization.
Bilateral symmetry; triploblastic; protostome; Platyhelminthes, Mollusca and Annelida.
Platyhelminthes have what type of coelom? Many species that we studied are
parasitic/free-living. Acoelomates; parasitic.
Plathelminthes have a pharynx. What is it for? It’s an inverted mouth for eating.
The final host is important to a parasite because that is where sexual reproduction occurs;
it is necessary to complete the life cycle.
Parasites have important characterisitics: They do not tend to kill their host, they have an
increased reproductive effort and they do change the behavior of their host.
The classes Tubellaria, Trematoda and Cestoda all belong to what phylum? Are they
parasitic, or free-living? They belong to Platyhelminthes. Tubellaria is free-living, and
Trematoda and Cestoda are parasitic.
Mollusca differ from platyhelminthes, in that they are coelomates and have a complete
digestive system.
Describe an open vs. closed circulatory system. An open system has a heart that pushes
blood into the body (that is then circulated by the organism’s muscles). A closed system
has blood that is always contained within vessels and the heart.
Mollusca have five parts to their body plan. What are they and what are they for? Foot for
locomotion, mantle for secreting the shell, visceral mass is the bag of organs, shell for
protection/rigidity and gills for repiration.
What are the three classes in Mollusca (that we studied)? Give an organism as an
example of each. Gastropoda, such as snails or slugs; Bivalvia such as clams, mussels or
oysters; and Cephalopoda, such as octopuses or squids.
Annelids: which type of circulatory system, what type of skeleton, what type of coelom.
All annelids have distinct body segmentation. Why is it important? Closed circulatory
system, hydrostatic skeleton, coelomates. Segmentation is important for the specialization
of different regions of the body.
What is the ecological importance of annelids? They digest organic matter/dirt and pass
casts, which are excellent fertilizer rich with minerals. They help aerate soil too.
42. Ecdysozoans: Name its symmetry, tissue organization, embryonic development, 2 phyla
within this group. What process is this group named for? Bilateral symmetry,
triploblastic, protostome, Nematoda and Arthropoda. It’s named for the molting of the
exoskeleton during growth.
43. Nematodes have an exoskeleton, called a cuticle, which is made of collagen.
44. What type of coelom do nematodes have? How do they move? They are
pseudocoelomates. They move by “thrashing”—contracting muscles against the cuticle.
45. There are two ecological roles of nematodes: decomposers and parasites, which can
affect both humans AND plants!
46. Arthropods are EXTREMELY successful. What are the four characteristics related to
their success? Segmented bodies, hard exoskeleton, jointed appendages and welldeveloped head and sensory organs.
47. The exoskeleton of arthropods is made of chitin, just like fungi. How is the exoskeleton
important? It protects the organism, prevents water loss and is an attachment site for
muscles.
48. How are jointed appendages considered advantageous for arthropods? Appendages have
become more specialized for specific functions.
49. Arthropods have an open circulatory system and a variety of organs for respiration.
50. For the four clades of arthropods, name: the number of body regions, number of pairs of
legs, presence of antennae, an example of an organism. Chelicerata: 2 body regions, 4
pairs of legs, no antennae, spiders. Crustacea: 2 body regions, 5+ pairs of legs, 2 pairs of
antennae, shrimp or crabs. Myriapod: 2 body regions, many legs, one pair of antennae,
millipedes or centipedes. Insecta: 3 body regions, 3 pairs of legs, one pair of antennae,
insects (grasshoppers, butterflies, gnats, etc.)
51. True or False: Crustaceans are the most successful group of arthropods. False (Insecta is!)
52. What are the three major adaptations of insects that led to their success? Flight,
specialized mouth parts and metamorphosis.
53. What are the three ecological effects of insects? Species pollinate plants, are vectors for
disease and compete with humans for food.
54. Deuterostomia: Name its symmetry, tissue organization, embryonic development, 2 phyla
within this group. Bilateral symmetry, triploblastic, deuterostomes, Echinodermata and
Chordata.
55. True or False: Starfish are bilaterally symmetric. True
56. What are the three subphyla of the chordates? Which one is without a head region?
Urochordata (no head region), cephalochordate and vertebrata.
57. All chordates have what four characteristics? Describe each. Notochord, a flexible rod
located between the nerve cord and gut, providing skeletal support for muscle
attachment; dorsal hollow nerve cord, develops into the central nervous system;
pharyngeal slits, openings to the outside of the body at the pharynx for gas and water
exchange; and a muscular post-anal tail, a tail found after the anus.
58. True or False: Vertebrates are the second largest group or organisms, behind arthropods.
False (they are only 5% of all organisms!)
59. What distinguishes vertebrates from the rest of the chordates? Distinct cephalization,
vertebral column that encloses the nerve chord (has the function of the notochord),
endoskeletons that grow with the animal and a closed circulatory system (more efficient
movement of things around the body).
60. There were many evolutionary events in the vertebrates. Agnata are the oldest vertebrate
group and thus don’t have jaws, which was the first evolutionary event. All vertebrates
that have jaws are called gnathostomes.
61. Another evolutionary event was of four footed vertebrates, or tetrapods. How was this
advantageous? Their limbs could support weight, leading to bigger animals on land.
62. Amphibians have eggs without a shell and do require water for reproduction.
63. Amniotes refers to a type of egg. The three things that this contains are what? How was
this evolution advantageous? Membranes, fluid and (sometimes) shells. It allowed
embryonic development to occur on land by protecting the embryo from water loss.
64. True or False: Birds belong in the clade Mammalia. False (they belong in Reptilia)
65. Birds are highly adapted for flight in three ways. What are they? How is flight beneficial?
Reduced organ systems (for less weight), airy or “honeycomb” bone structure (for less
weight) and feathers (modified scales). Flight was beneficial for exploitation of flying
insects, to escape from predators and long-distant migration.
66. What are the 4 mammalian characteristics that separate them from the rest of the
Deuterostomes? Mammary glands (for production of milk), hair, diaphragm (muscle for
ventilating lungs) and specialized teeth (for specific eating habits).
67. There are three major mammalian groups: egg laying, marsupial and placental. How are
they different? In placental mammals, embryonic development is completed within a
uterus within the mother’s body.
68. True or False: Humans and chimpanzees share a common ancestor, meaning humans
evolved from chimps. False (the common ancestor means they DIDN’T evolve from
chimps)
69. True or False: Humans and chimpanzees are genetically similar. True