Introduction to Invertebrates Flashcards
1
Q
What are the key characteristics of bilaterian animals?
A
Bilateral symmetry and three germ layers
2
Q
In a phylogenetic tree
A
what is a basal taxon?
3
Q
What is a coelom?
A
A fluid-filled body cavity completely lined with mesoderm
4
Q
What is a hemocoel?
A
A body cavity where blood circulates - not completely lined with mesoderm
5
Q
What does acoelomate refer to?
A
An animal lacking a coelom or body cavity
6
Q
What are the key characteristics of bilaterian animals?
A
- Bilateral symmetry
- Three germ layers
- A complete digestive tract.
7
Q
What is a basal taxon in a phylogenetic tree?
A
The earliest diverging lineage in a phylogenetic tree, representing the common ancestor of all other taxa in the tree.
8
Q
What phylum do sponges belong to?
A
Porifera
9
Q
How do sponges primarily feed?
A
Filter feeding
10
Q
What is the central cavity of a sponge called?
A
Spongocoel
11
Q
What type of cells in sponges are responsible for engulfing bacteria and food particles?
A
Choanocytes
12
Q
What is the function of amoebocytes in sponges?
A
They take up food digest it and carry nutrients to other cells.
13
Q
What material can sponge spicules be made of?
A
Calcium carbonate or silica
14
Q
What is the gelatinous region between the two layers of cells in a sponge called?
A
Mesohyl
15
Q
What is the term for an organism that functions as both male and female in sexual reproduction?
A
Hermaphrodite
16
Q
What is the significance of amoebocytes being totipotent?
A
They can become other types of sponge cells.
17
Q
What is the larger opening through which water flows out of a sponge called?
A
Osculum
18
Q
What is sequential hermaphroditism?
A
It is when an organism functions first as one sex and then as the other.
19
Q
What is the primary function of cnidocytes in cnidarians?
A
Defense and prey capture
20
Q
What is the central digestive compartment in cnidarians called?
A
Gastrovascular cavity
21
Q
Which form of cnidarian is primarily sessile?
A
Polyp
22
Q
What type of body symmetry do cnidarians exhibit?
A
Radial symmetry
23
Q
Which cnidarian form is known for its free-swimming capability?
A
Medusa
24
Q
What are the two major clades of the phylum Cnidaria?
A
Medusozoa and Anthozoa
25
What specialized cnidae contain a toxic stinging thread?
Nematocysts
26
How do cnidarians coordinate their movements?
Noncentralised nerve net
27
What is the primary method of movement for medusae?
Passive drifting and contractions of the bell-shaped body
28
What is the function of the gastrovascular cavity in cnidarians?
Digestion and nutrient distribution
29
Which clade includes all cnidarians that produce a medusa?
Medusozoa
30
What is a characteristic feature of cubozoans?
Box-shaped medusa stage
31
What is the primary habitat of most cubozoans?
Tropical oceans
32
Which hydrozoan is known to exist only in polyp form?
Hydras
33
What is the life cycle stage of scyphozoans that is typically brief or absent in open ocean species?
Polyp stage
34
What is the primary danger associated with the sting of Chironex fleckeri?
Intense pain and potential for respiratory failure
35
What clade do sea anemones and corals belong to?
Anthozoa
36
What form do anthozoans occur in?
Polyps
37
What material do many coral species secrete to form their exoskeleton?
Calcium carbonate
38
What is a major threat to coral reefs and anemones?
Climate change
39
What type of symmetry do members of the clade Bilateria exhibit?
Bilateral symmetry
40
What is the body cavity of most bilaterians called?
Coelom or haemocoel
41
What is the name of the oldest widely accepted bilaterian fossil?
Kimberella
42
During which period did many bilaterian groups first appear in the fossil record?
Cambrian explosion
43
Which of the following is NOT one of the three major clades of bilaterally symmetrical animals? a) Cnidaria b) Ecdysozoa c) Deuterostomia d) Lophotrochozoa
A. Cnidaria
44
What structure do some lophotrochozoans develop that functions in feeding?
Lophophore
45
How many phyla are classified within the Lophotrochozoa clade?
18
46
Which of the following is NOT one of the six diverse lophotrochozoan phyla introduced? a) nematodes b) Molluscs c) flatworms d) Annelids
A. Nematodes
47
Hermaphrodite (hur-maf′-ruh-dīt′)
An individual that functions as both male and female in sexual reproduction by producing both sperm and eggs.
48
Planarian
A free-living flatworm found in ponds and streams.
49
Brachiopod (bra′-kē-uh-pod′)
A marine lophotrochozoan with a shell divided into dorsal and ventral halves; also called lamp shells.
50
Visceral mass
One of the three main parts of a mollusc; the part containing most of the internal organs.
51
What are the three main parts of a mollusc?
1. Visceral mass
2. Foot
3. Mantle.
52
Water vascular system
A network of hydraulic canals unique to echinoderms that branches into extensions called tube feet which function in locomotion and feeding.
53
Polyp
The sessile variant of the cnidarian body plan. The alternate form is the medusa.
54
Cnidocyte (nī′-duh-sīt)
A specialised cell unique to the phylum Cnidaria; contains a capsule-like organelle housing a coiled thread that when discharged explodes outwards and functions in prey capture or defence.
55
Chelicera (kē-lih′-suh-ruh)
One of a pair of clawlike feeding appendages characteristic of chelicerates.
56
Medusa (muh-dū′-suh)
The floating mouth-down form of the cnidarian body plan. The alternate form is the polyp.
57
Gastrovascular cavity
A central cavity with a single opening in the body of certain animals (including cnidarians and flatworms) that functions in both the digestion and distribution of nutrients.
58
Protonephridium (prō′-tō-nuh-frid′-ē-um)
An excretory system consisting of a network of tubules lacking internal openings (such as the flame bulb system of flatworms)
59
Chelicerate (kē-lih-suh′-rāte)
An arthropod that has chelicerae and a body divided into a cephalothorax and an abdomen. Living chelicerates include; sea spiders, horseshoe crabs, scorpions, ticks and spiders.
60
Book lung
An organ of gas exchange in spiders consisting of stacked plates contained in an internal chamber.
61
Parthenogenesis (par′-thuh-nō′-jen′-uh-sis)
A form of asexual reproduction in which females produce offspring from unfertilised eggs.
62
Radula
A straplike scraping organ used by many molluscs during feeding.
63
Arachnid
- A member of a subgroup of the major arthropod clade Chelicerata.
- Arachnids have six pairs of appendages, including: four pairs of walking legs
- Spiders, scorpions, ticks, and mites.
64
Exoskeleton
A hard encasement on the surface of an animal that provides protection and points of attachment for muscles (such as the shell of a mollusc or the cuticle of an arthropod)
65
Filter feeder
An animal that feeds by using a filtration mechanism to strain small organisms or food particles from its surroundings.
66
Choanocyte (kō-an′-uh-sīt)
A flagellated feeding cell found in sponges. Also called a collar cell, it has a collar-like ring that traps food particles around the base of its flagellum.
67
Echinoderm (i-kī′-nō-derm)
- A slow-moving or sessile marine deuterostome with a water vascular system and, in larvae, bilateral symmetry.
- Echinoderms include: sea stars, brittle stars, sea urchins, feather stars, and sea cucumbers.
68
Pancrustacean
A member of a diverse arthropod clade that includes: lobsters, crabs, barnacles, and other crustaceans as well as insects and their six-legged terrestrial relatives.
69
Open circulatory system
A circulatory system in which fluid called haemolymph bathes the tissues and organs directly and there is no distinction between the circulating fluid and the interstitial fluid.
70
Spongocoel (spon′-jō-sēl)
The central cavity of a sponge.
71
Ectoproct
A sessile colonial lophotrochozoan; also called a bryozoan.
72
Mantle cavity
A water-filled chamber that houses the gills anus and excretory pores of a mollusc.
73
Complete metamorphosis
The transformation of a larva into an adult that looks very different, and often functions very differently, in its environment to the larva.
74
Osculum (os′-kyuh-lum)
A large opening in a sponge that connects the spongocoel to the environment.
75
Cuticle (kyū′-tuh-kul)
Any of a variety of tough but flexible non-mineral outer coverings of an organism or parts of an organism which provide protection.
76
Alimentary canal (al′-uh-men′-tuh-rē)
A complete digestive tract
77
Ammonite
A member of a group of shelled cephalopods that were important marine predators for hundreds of millions of years until their extinction at the end of the Cretaceous period (65.5 million years ago).
78
Arthropod
- A segmented ecdysozoan with a hard exoskeleton and jointed appendages.
- Familiar examples include: insects, spiders, millipedes, and crabs.
79
Nematocyst (nem′-uh-tuh-sist′)
- In a cnidocyte of a cnidarian
- A capsule-like organelle containing a coiled thread that when discharged can penetrate the body wall of the prey.
80
Myriapod (mir′-ē-uh-pod′)
- A terrestrial arthropod with many body segments and one or two pairs of legs per segment.
- Millipedes and centipedes are the two major groups of living myriapods.
81
Amoebocyte
- An amoeba-like cell that moves by pseudopodia and is found in most animals.
- Depending on the species, it may digest and distribute food, dispose of wastes, form skeletal fibres, fight infections, or change into other cell types.
82
Eurypterid (yur-ip′-tuh-rid)
An extinct carnivorous chelicerate; also called a water scorpion.
83
Incomplete metamorphosis
A type of development in certain insects
84
Mantle
One of the three main parts of a mollusc; a fold of tissue that drapes over the mollusc’s visceral mass and may secrete a shell.
85
Tube foot
- One of numerous extensions of an echinoderm’s water vascular system. - Tube feet function in locomotion and feeding.
86
Moulting
A process in ecdysozoans in which the exoskeleton is shed at intervals allowing growth by the production of a larger exoskeleton.
87
Mesohyl
A gelatinous region between the two layers of cells of a sponge.
88
What do cnidarians lack?
Brain/head and muscle tissues
89
Cephalization
The formation of a head region
90
What has cephalization resulted in?
- Sensory structures (eyes, etc) at head
- Brain development in association with sensory structures
- Mouth at cephalic end
