Ch 33: An Introduction To Invertebrates Flashcards
1
Q
What percentage of known animal species do invertebrates account for?
A
Over 95%.
2
Q
What is the habitat range of invertebrates?
A
They occupy almost every habitat on Earth.
3
Q
What is the size range of invertebrates?
A
From microscopic to 18 m long.
4
Q
How many known species are in Kingdom Animalia?
A
1.3 million.
5
Q
What is the estimated total number of animal species?
A
10–20 million.
6
Q
What are sponges classified as?
A
Basal animals that lack tissues.
7
Q
What defines the body structure of a sponge?
A
A sac perforated with pores.
8
Q
What type of feeder are sponges?
A
Filter feeder.
9
Q
What is the central cavity of a sponge called?
A
Spongocoel.
10
Q
What is the function of the osculum in sponges?
A
It allows water to flow out.
11
Q
What type of cells do sponges have that engulf bacteria?
A
Choanocytes.
12
Q
What are amoebocytes in sponges responsible for?
A
Digesting food, transporting nutrients, and making skeletal fibers.
13
Q
What type of reproduction do most sponges exhibit?
A
Hermaphroditism.
14
Q
What is the term for sponges functioning first as one sex and then as the other?
A
Sequential hermaphroditism.
15
Q
What type of animals are eumetazoans?
A
Animals with true tissues.
16
Q
Which phylum is considered the oldest in eumetazoans?
A
Cnidaria.
17
Q
What forms does Cnidaria include?
A
Corals, hydras, and jellies (jellyfish).
18
Q
What is the basic body plan of Cnidarians?
A
A sac with a central digestive compartment (gastrovascular cavity).
19
Q
What are the two variations of Cnidarian body plans?
A
Polyp and medusa.
20
Q
What are cnidocytes?
A
Unique cells used in defense and prey capture.
21
Q
What are nematocysts?
A
Specialized organelles within cnidocytes that eject a stinging thread.
22
Q
What does the gastrovascular cavity serve as for Cnidarians?
A
A hydrostatic skeleton.
23
Q
What are the two major clades within Phylum Cnidaria?
A
Medusozoa and Anthozoa.
24
Q
What is the predominant stage in the life cycle of scyphozoans?
A
Medusa.
25
What do anthozoans include?
Sea anemones and corals.
26
What do coral polyps form?
Rocklike reefs.
27
What threatens coral reefs?
Pollution, overharvesting, ocean acidification, and climate change.
28
What are bilaterians characterized by?
Bilateral symmetry and triploblastic development.
29
What does the clade Lophotrochozoa include?
Flatworms, rotifers, ectoprocts, brachiopods, molluscs, and annelids.
30
What is the defining feature of flatworms?
They are dorsoventrally flattened acoelomates.
31
What is the excretory apparatus of flatworms called?
Protonephridia.
32
What are flame bulbs in flatworms?
Ciliated structures in the protonephridia.
33
What are the two lineages of flatworms?
Catenulida and Rhabditophora.
34
What are planarians?
Free-living rhabditophorans that live in fresh water.
35
What do trematodes typically require for their life cycle?
An intermediate host.
36
What do tapeworms lack?
A mouth or gastrovascular cavity.
37
What is the anterior end of a tapeworm called?
Scolex.
38
What are proglottids in tapeworms?
Units that contain sex organs.
39
What phylum do rotifers and acanthocephalans belong to?
Syndermata.
40
What is the feeding structure of rotifers called?
Trophi.
41
How do some rotifers reproduce?
Parthenogenesis.
42
What is unique about Bdelloidea rotifers?
They have been asexual for over 50 million years.
43
What is the defining characteristic of acanthocephalans?
They are sexually reproducing parasites of vertebrates.
44
What do all acanthocephalans lack?
A complete digestive tract.
45
What do some acanthocephalans do to their intermediate hosts?
Manipulate their behavior to increase transmission to the final host.
46
What are phalans?
Sexually reproducing parasites of vertebrates.
47
What is a key characteristic of acanthocephalans?
They lack a complete digestive tract.
48
What are acanthocephalans commonly called?
Spiny-headed worms.
49
What is an example of an acanthocephalan?
Paratenuisentis ambiguus.
50
What type of life cycles do acanthocephalans have?
Complex life cycles with multiple hosts.
51
How do some acanthocephalans manipulate their intermediate hosts?
By altering the host's behavior to increase transmission to the final host.
52
What feeding structure do ectoprocts and brachiopods possess?
Lophophore.
53
What is a characteristic of ectoprocts?
They are sessile colonial animals.
54
How do brachiopods differ from clams?
Their two shell halves are dorsal and ventral rather than lateral.
55
What does the phylum Mollusca include?
Snails, slugs, oysters, clams, octopuses, and squids.
56
What are the three main parts of a mollusc's body plan?
* Muscular foot
* Visceral mass
* Mantle
57
What is a radula?
A straplike structure used by many molluscs to scrape up food.
58
What are the eight major clades of molluscs?
* Polyplacophora (chitons)
* Gastropoda (snails and slugs)
* Bivalvia (clams, oysters)
* Cephalopoda (squids, octopuses)
59
What is the function of the muscular foot in molluscs?
Used for movement.
60
What is a characteristic of gastropods?
They usually have a single, spiraled shell.
61
How do bivalves feed?
Using gills for suspension feeding.
62
What is unique about cephalopods compared to other molluscs?
They have a closed circulatory system.
63
What are ammonites?
Shelled cephalopods that were dominant invertebrate predators.
64
What is a characteristic of annelids?
They are segmented worms.
65
What are the two clades of annelids based on phylogenomic analysis?
* Errantia
* Sedentaria
66
What is a defining feature of errantians?
Many have well-developed jaws for predation.
67
What is a common feature of sedentarians?
They tend to be less mobile.
68
What is the role of earthworms in soil?
They till, aerate, and improve soil texture.
69
What are ecdysozoans?
Animals with a tough external coat called a cuticle.
70
What is ecdysis?
The process of shedding the cuticle.
71
What are nematodes?
Roundworms with cylindrical bodies.
72
What is a characteristic of nematodes' body structure?
They have an alimentary canal but lack a circulatory system.
73
What is an example of a nematode that affects humans?
Trichinella spiralis.
74
What is the estimated number of arthropod species on Earth?
About a billion billion.
75
What are the three major lineages of arthropods?
* Chelicerates
* Myriapods
* Pancrustaceans
76
What are chelicerates named for?
Clawlike feeding appendages called chelicerae.
77
What do arachnids have in terms of appendages?
Six paired appendages.
78
What is the function of pedipalps in arachnids?
They function in sensing, feeding, defense, or reproduction.
79
What do myriapods include?
* Millipedes
* Centipedes
80
What is a common habitat for myriapods?
Terrestrial environments.
81
What is one use of silk produced by many spiders?
Construction of a web for capturing prey
## Footnote
Spiders utilize silk for various purposes including escape, egg covering, and courtship.
82
What does Myriapoda include?
Millipedes and centipedes
83
How many legs do millipedes have per trunk segment?
Two pairs of legs
84
What do millipedes primarily eat?
Decaying leaves and other plant matter
85
What type of diet do centipedes have?
Carnivorous
86
How many legs do centipedes have per trunk segment?
One pair of legs
87
What is the clade that includes insects and crustaceans?
Pancrustacea
88
What environments do crustaceans inhabit?
Marine, freshwater, and terrestrial habitats
89
What do small crustaceans use to exchange gases?
Cuticle
90
What are isopods?
One of the largest groups of crustaceans
91
What are decapods?
Relatively large crustaceans including lobsters, crabs, crayfish, and shrimp
92
What is the function of barnacles' feeding appendages?
To strain food from water
93
What is the clade that includes insects?
Hexapoda
94
How old are the oldest insect fossils?
415 million years old
95
What evolutionary feature improved insects' ability to evade predators?
Flight
96
What is incomplete metamorphosis?
Development where young resemble small, wingless adults
97
What is complete metamorphosis?
Development with larval stages specialized for eating and growing
98
What do most insects use for reproduction?
Sexual reproduction with separate males and females
99
What are the two orders of wingless insects?
Archaeognatha and Zygentoma
100
What is a characteristic of Archaeognatha?
Wingless insects found in moist, dark habitats
101
What is a defining feature of Zygentoma?
Small, wingless insects with a flattened body
102
What do coleopterans represent?
Beetles, the most species-rich order of insects
103
How many species are in the Diptera order?
151,000 species
104
What are halteres?
Balancing organs formed from the second pair of wings in dipterans
105
What type of insects are hymenopterans?
Highly social insects including ants, bees, and wasps
106
What do lepidopterans include?
Butterflies and moths
107
What is a characteristic of hemipterans?
Include 'true bugs' with piercing or sucking mouthparts
108
What adaptations do orthopterans have?
Large hind legs adapted for jumping
109
What is a major role of insects in ecosystems?
Predators, prey, parasites, and decomposers
110
What do echinoderms include?
Sea stars and sea urchins
111
What are the developmental characteristics shared by deuterostomes?
Radial cleavage and formation of the anus from the blastopore
112
What is the water vascular system in echinoderms?
A network of hydraulic canals that branches into tube feet
113
What do sea stars use their tube feet for?
Locomotion and feeding
114
What is the primary shape of sea urchins?
Spherical
115
What distinguishes sea cucumbers from other echinoderms?
Lack spines and have reduced endoskeletons
116
What does phylum Chordata include?
Vertebrates and two groups of invertebrates (lancelets and tunicates)
117
How are chordates related to echinoderms?
Closely related but evolved independently for at least 500 million years
118
What is a characteristic of crinoidea?
Sea lilies and feather stars with arms used in suspension feeding
