Animals Flashcards
1
Q
What are the 4 characteristics which makes an animal?
A
1) How they acquire and assimilate organic nutrients: animals innovated the gut.
2) Their mode of sexual reproduction and embryonic development (germ layers)
3) Hox genes that dictate embryonic development
4) Muscle and nervous tissue
2
Q
When is the gut formed and from what germ layer in animals?
A
The gut develops from the endoderm during gastrulation.
3
Q
What are the 2 developmental fates of animals?
A
1) protostome development
2) deuterostome development
4
Q
What are the stages of embryonic development from sexual reproduction?
A
Zygote -(cleavage)> 8 cell stage -(cleavage)> Blastula -> gastrulation -> gastrula
5
Q
What kinds of organisms undergo protostome development?
A
Molluscs and annelids
6
Q
What kinds of organisms undergo deuterstome development?
A
Echinoderms and chordates
7
Q
Are protostomes and deuterostomes spiral or radial and determinate or indeterminate?
A
Protostomes: spiral and determinate
Deuterostomes: radial and indeterminate
8
Q
Does the mouth or anus of protostomes develop from blastopore?
A
Mouth develops from blastopore
9
Q
Does the mouth or anus of deuterstomes develop from blastopore?
A
Anus develops from blastopore
10
Q
What family of genes are the genes in control of gastrulation and organogenesis a part of?
A
Hox genes
11
Q
How many genes are contained in a single hox gene set?
A
A single Hox gene set contains up to 13 genes.
12
Q
The increase in the complexity of organs is a result of what?
A
the increase in complexity of organs is the result of the increase in the number of developmental genes
13
Q
What are the 2 embryonic tissues developed by diploblastic animals?
A
ectoderm and endoderm
14
Q
True or false: all bilaterians are triploblastic?
A
TRUE
15
Q
What are the 3 embryonic tissues in triploblastic animals?
A
ectoderm, endoderm and mesoderm
16
Q
What’s the definition of a coelom?
A
A body cavity is a fluid-filled space called a coelom
17
Q
How are the germ layers arranged in coelomates?
A
the mesoderm covers both the ectoderm and endoderm creating a cavity that is entirely lined by mesoderm tissue
18
Q
How are the germ layers arranged in pseudocoelomates?
A
In pseudocoelomates, the mesoderm covers only the ectoderm.
19
Q
What are the 2 functions of fluid-filled cavities?
A
1) protect organs against injury
2) allows them to move independently from the rest of the body
20
Q
What is the name of animals that lack fluid-filled coeloms?
A
acoelomates
21
Q
What is the cavity in acoelomates filled with?
A
The cavity in such animals is filled with cells derived from the mesoderm.
22
Q
What is the peritoneum?
A
thin slippery membrane that lines the body cavity (borders the mesoderm). The peritoneum is visible under the microscope
23
Q
Why are sponges considered metazoans?
A
Because they lack many of the defining features of animals
24
Q
Are sponges closer to eumetazoans or protozoans?
A
Eumetazoans
25
What does eumetazoan mean?
True animal
26
Proto=?
first
27
Meta=?
next
28
Eu=?
true
29
zoa=?
animals
30
What 4 characteristics of sponges made it so that they are considered metazoans?
1) Multicellular
2) Heterotrophic
3) lack cell walls
4) produce sperm cells
31
What 4 characteristics do sponges have that make them lesser than a eumetazoan?
1) lack true tissue; haphazard organization of cells
2) lack hox genes
3) no symmetry
4) 4) lack true tissue
32
What is the spongocoel of a sponge?
the central cavity: water is drawn through pores into the spongecoel and flows out from the osculum (some can have several osculae)
33
When water is drawn in through pores and into the spongecoel, where does the water exit in sponges?
osculum
34
Why does gas exchange in sponges occur via diffusion?
Because the body is 2 cell-layers thick
35
What do Amoebocytes do in sponges?
they move through the gelatinous mesohyl (connective tissue) and they carry nutrients to other cells and synthesize spicules and spongin
36
What are spicules?
protein fibers reinforced with calcium carbonate synthesized by amoebocytes
37
What is spongin?
a flexible protein synthesized by amoebocytes
38
How do sponges eat?
food particles stuck on the collar of choanocytes are engulfed by phagocytosis
39
How do sponges digest their food?
Unlike eumetazoans, sponges digest food intracellularly (i.e. not within a specialized compartment) -> lack true tisue thus lack specialized compartments
40
Where are gametes contained in sponges?
Mesohyl = a type of connective tissue in sponges
41
True or false: there is no cleavage, blastula, or gastrula in sponge development?
TRUE
42
Are cnidarians triplo or diplo?
diploblastic
43
What is mesoglea and what 2 things does it do in cnidaria?
the connective tissue that...
1) keeps the gastrodermis and epidermis (2 sheets of epithelial tissues) anchored in cnidaria
2) contributes to buoyancy in medusa
44
Where is food digested in cnidaria?
gastrovascular cavity
45
How are gonads, and muscle and nerve cells created in cnidaria?
epithelial cells from the endoderm migrate to the mesoglea and differentiate into gonads, muscle and nerve cells
46
True or false: Cnidaria have mesoderm?
FALSE: they are diploblastic
47
True or false: Muscle and nervous tissue have their origins in cnidarians?
TRUE
48
What are the 2 major cnidarian clades?
1) medusozoa
2) anthozoa
49
What are medusozoans?
include all cnidarians that produce a medusa (jellyfish)
50
True or false: the medusa is the main stage in the life cycle of most medusozoans?
TRUE
51
what are anthozoans?
occur only as polyps including corals and sea anemones
52
What relationship do corals have with algae?
Corals often form symbiosis with algae and secrete a hard exoskeleton (external skeleton). Each generation grows on the skeletal remains of the previous generation, forming “rocks” that provide habitat for other species
53
What % of all animal species are represented by bilaterians?
99%
54
How is the lophotrochozoans clade identified?
clade identified by molecular data
55
Which clade has the widest range of animal body forms?
Lophotrochozoa
56
What 6 organisms are included in the Lophotrochozoan clade?
1) flatworms (platyhelminthes)
2) rotifers
3) ectoprocts
4) brachiopods
5) molluscs
6) annelids (segmented worms)
57
what are 2 distinct features of platyhelminthes?
1) unsegmented
2) dorsoventrally flattened worms
58
How many openings do platyhelminthes have and where does it lead to?
Flatworms have just one opening that leads to the gastrovascular cavity
59
What do we start to see in the platyhelminthes phylum?
we start to see clear compartmentalization: mouth, pharynx & gastrovascular cavity for processing food & the protonephridium for waste elimination and osmoregulation
60
What is the function of a protonephridium?
waste elimination and osmoregulation
61
Flatworms, in particular, planarians have a complex nervous system derived from what and what 2 parts are included in this complex nervous system?
derived from ectoderm:
1) light-sensitive eyespots
2) centralized nerve nets
62
What are the 3 types of muscle tissues derived from mesoderm do flatworms have and what do the aid in?
1) circular
2) longitudinal
3) dorsoventral muscles
-> all aid in movement
63
True or false: all 3 types of muscle tissues in flatworms can't be observed under the compound light microscope?
FALSE: they can be observed under the compound microscope
64
What germ layer does the excretory system in flatworms (protonephridium) originate from?
originates from the ectoderm germ layer
65
what are 2 types of parasitic flatworms?
1) trematodes
2) tapeworms
66
What is an example of a trematode that can live in human hosts?
Flukes
67
What do tapeworms lack and why is this ironic to you?
Tapeworms lack a digestive system, this is ironic because they parasitize the guts of vertebrates, absorbing nutrients by diffusion alone
68
What are the 3 parts of a tapeworm?
1) scolex = head with suckers and hooks to attach to intestinal wall
2) posterior to scolex is the neck
3) neck is followed by proglottids (segments)
69
What happens to the old proglottids in tapeworms?
As new segments are formed, older segments are pushed back
70
How do adult tapeworm reproduce?
Tapeworms are hermaphroditic: each proglottid has male and female reproductive organs: When a segment is full of fertilized eggs, it detaches itself from the adult tapeworm and is passed in the feces of the host.
71
True or false: rotifers are often smaller than protists?
TRUE
72
Are rotifers coelomates, acoelomates or pseudocoelomates?
pseudocoelomates
73
Since rotifers are often smaller than protists, does it mean that they're unicellular?
No, they're multicellular creatures with specialized organ systems including a complete digestive tract and a fluid-filled pseudocoelom
74
How are nutrients distributed in rotifers?
Body movements help to distribute nutrients
75
What is the distinct feature of rotifers?
crown of cilia around the mouth that draws water in like a vortex
76
How do rotifers reproduce?
Rotifers reproduce by parthenogenesis, in which females produce offspring from unfertilized eggs. Some species are unusual in that they lack males entirely.
77
What are 3 characteristics of annelids?
1) true coelomates
2) segmented bodies
3) complete digestive tract
78
what are parapodia that annelids have?
a pair of paddle-like structures on each body segment
79
What does each parapodium have in annelids?
Each parapodium has numerous chaetae: stiff bristles made of chitin
80
What are chaetae?
stiff bristles made of chitin
81
What is a function of parapodia in annelids?
The parapodia are richly supplied with blood and thus also function as gills (for gas exchange).
82
True or false: leeches are a part of the platyhelminthes phylum?
FALSE: they are annelids
83
What chemical do leeches secrete in order to prevent blood from coagulating?
hirudin
84
What is the structure of earthworms?
Earthworms have a highly compartmentalized alimentary canal: mouth, pharynx, esophagus, crop, gizzard, intestine, anus. Septa partition the segments. Each segment also has four pairs of chaetae for locomotion on each. Metanephridium (derived from mesoderm) in association with blood vessels is present in each segment
85
What are the 7 compartments of the alimentary canal of worms?
1) mouth
2) pharynx
3) esophagus
4) crop
5) gizzard
6) intestine
7) anus
86
At each segment of earthworms, how many chaetae do they have for locomotion?
4
87
What is also present in each segment of earthworms?
Metanephridium (derived from mesoderm) in association with blood vessels is present in each segment
88
What is the metanephridium of earthworms derived from?
mesoderm
89
Do earthworms have a closed or open circulatory system?
closed
90
What clade is the most speciose animal group?
Ecdysozoan
91
What defines an Ecdysozoan?
Ecdysozoans are covered by a tough coat called a cuticle. The cuticle is shed or molted through a process called ecdysis.
92
What is the shedding or molting of the cuticle in Ecdysozoans called?
process is called ecdysis
93
What are the 2 largest phyla in the Ecdysozoan clade?
1) nematodes
2) arthropods
94
What are 4 characteristics of nematodes (round worms)?
1) pseudocoelomates
2) complete digestive tract
3) lack respiratory and circulatory system
4) Muscles are aligned longitudinally along the length of the body
95
What limits the movement of nematodes to thrashing left to right?
the arrangement of the muscles which are aligned longitudinally along the length of the body limits their movement
96
what kind of symmetry do echinoderms have?
adult echinoderms have radial symmetry with multiples of five, but larvae have bilateral symmetry
97
What is the structure of the echinoderm (10 parts)?
1) thin epidermis covers an endoskeleton of hard calcareous plates
2) Gills on the skin surface
3) central disk has a nerve ring and nerve cords radiating from the ring into the arms
4) Digestive glands secrete digestive juices and aid in the absorption and storage of nutrients
5) A short digestive tract runs from the mouth on the bottom of the central disk to the anus on top of the disk
6) Spines on the surface of sea stars = defence
7) Water flows in and out of the water vascular system through the madreporite
8) The water vascular system consists of a ring canal and five radial canals, each running in a groove down the entire length of an arm
9) Branching from each radial canal are hundreds of hollow, muscular tube feet filled with fluid. Each tube foot consists of a bulb-like ampulla and a podium
98
What occurs when the muscles of the ampulla contract in echinoderms?
water is forced into the podium and causes the podium to elongate
99
What occurs when the longitudinal muscles of the podium contract in echinoderms?
water is forced back into the ampulla
100
What can tube feet do in echinoderms?
Tube feet are also useful for grabbing prey
101
How many classes are in the mullusca phylum?
7
102
true or false: mullusca members are bilaterally symmetrical and triploblastic?
TRUE
103
What are the 7 classes of molluscs?
1) Aplacorphora,
2) Monoplacophora,
3) Scaphopoda,
4) Polyplacophora,
5) Gastropoda,
6) Bivalvia,
7) Cephalopoda
104
What's the acronym made to remember the 7 classes inside the mullusca phylum?
Acronym: All Molluscs Send Pleasing Good-Byes Cautiously
105
What are the 4 key features of the molluscan body?
1) muscular foot
2) visceral mass = cluster of organs
3) mantle
4) radula
106
What are the 4 functions of the foot?
locomotion, burrowing, anchoring, and supporting internal organs.
107
The epidermis of the foot of monoplacophorans, polyplacophorans and gastropods (ones that move around) secretes what?
includes gland cells that secrete mucus to hold glide and adhere to substrates.
108
What is the mantle?
(dorsal to mass) a slab of epidermis = mantle that drapes over visceral mass and extends past it creating a mantle cavity and is often covered with a cuticle
109
What do the epidermis cells of the dorsal mantle include in some classes?
In some classes, the epidermal cells of the dorsal mantle include highly secretory cells that secrete CaCO3 that will produce the shell.
110
What does dorsal mean?
Dorsal (or posterior) refers to the back portion of the body
111
What does ventral mean?
ventral (or anterior) refers to the front part of the body
112
What is the radula and what is it used for?
a rasping tooth-like structure made of chitin used for scraping algae from rocks
113
What is contained in the mantle cavity of many molluscan members?
Within this cavity are the gills used for gas exchange and anus.
114
True or false: the coelom is highly reduced in the molluscan phylum, so it won't be seen in lab?
TRUE
115
What part of snails is seen distinctly under dissecting microscope and can often identify snails solely based on this part?
Radula
116
What does the shell of each class look like?
1) Monoplacophorans (won’t cover), gastropods, and cephalopods typically have a conical shell with a single opening, which can be coiled in the gastropods and cephalopods
2) Scaphopods have a conical shell open at both ends
3) Bivalves have a shell composed of two halves, hinged dorsally
4) Polyplacophorans display eight dorsal shell plates, sometimes with spicules on their girdle.
5) Aplacophora molluscs have calcium carbonate spicules covering the entire body
117
What are 6 characteristics of chitons?
1) bilaterally symmetrical marine animals
2) armour of 8 calcareous plates
3) use foot like suction cup to grip rocks
4) radula used to scrape off rock surfaces
5) radula reinforced with iron oxides for greater strength
6) Respiratory organ = gills
118
What are the 2 classes of molluscs that colonize freshwater?
1) Bivalves
2) Gastropods
119
How do gastropods move?
They move slowly by rippling motions of the foot or by cilia
120
What kind of shell do gastropods have?
Most have a single, spiralled shell
121
What are the 3 functions of the spiralled shell?
protection from injury, dehydration, and predation
122
What member of gastropods lacks a shell?
Slugs: lack or have reduced shell
123
What part of slugs becomes a swimming appendage?
the foot and mantle becomes a swimming appendage.
124
What occurs only in gastropods during larval development?
All gastropods during larval development undergo torsion – the rotation of the visceral mass, mantle, and shell by 180˚
125
What is the outcome of torsion in gastropods?
The outcome of this twisting brings the mantle cavity and anus to an anterior position above the head.
126
What does the shell of bivalves look like?
The shell of bivalves is divided into two halves drawn together by strong adductor muscles
127
What does the mantle cavity of bivalves conatin?
contains gills
128
What are the 2 functions of the gills in bivalves?
1) feeding
2) gas exchange
129
How does water move in and out of bivalves?
Water (with suspended food) enters through the incurrent siphon, gills pick up O2 and filter feed. Water, wastes and gametes exit through an excurrent siphon.
130
Which of the 4 main characteristics of molluscs do bivalves lack?
Bivalves lack a head, hence no radula.
131
Do bivalves move, if so, how?
Most species are sedentary, but some have limited motility. The foot is laterally compressed and mostly used for digging and anchoring
132
How do you tell between the 4 groups of bivalves? (clams, oysters, mussels, and scallops)
1) Clams: typically have smooth, rounded shells
2) Oysters: have a rougher texture than mussel shells and can be brown, white or gray and more irregular shape
3) Mussels: have darker blue or black shells that are more oblong in shape and can have an iridescent sheen to them
4) Scallops: have distinctive "ribbed" edges on their shells
133
In cephalopods, what is their foot modified into?
arms
134
What is the mantle in cephalopods modified into?
modified into an excurrent siphon to forcefully eject water allowing for jet propulsion
135
True or false: cephalopods have an open circulatory system, well-developed sense organs, and a simple brain.
FALSE: closed circulatory system, well-developed sense organs, and a complex brain.
136
What is the sole shelled representative of the cephalopods?
nautilus
137
What are the differences between octopi, cuttlefish and squid?
octopuses have eight arms lined with suckers while squids and cuttlefish have both arms (eight of them) and two tentacles specialized at catching prey
138
What do the arms of nautilus look like?
The nautilus lacks tentacles but has many arms (more than 90) without suckers.
139
What is the arthropod body covered by?
covered by a cuticle– an exoskeleton made of layers of protein and the waterproof polysaccharide chitin -> sheds exoskeleton as it grows
140
What are the 3 suspected reasons for the long-standing success of arthropods?
1) segmented body plan armored with a hard exoskeleton.
2) Along each segment are specialized jointed appendages = more hox genes
3) Arthropods have the best dexterity of all invertebrates
141
What is the arthropod evolution characterized by?
Arthropod evolution is characterized by a decrease in the number of segments and an increase in appendage specialization
142
Greater specialization of body parts in arthropods is due to what?
the result of higher number of Hox genes and with key sequence changes
143
How many sets of hox genes do arthropods have?
Arthropods have a single set of a hox genes, but it has many more copies in the certain regions allowing for differentiation
144
What are the 3 sub-phyla of arthropods?
1) Chelicerates (lineages: horseshoe crabs, arachnids and sea spiders)
2) Myriapods (lineages: millipedes and centipedes)
3) Pancrustaceans (lineages: copepods, isopods, decapods, barnacles and hexapods (insects))
145
How was the sub-phylum chelicerates named?
named for clawlike feeding appendages called chelicerae that are used for grasping prey
146
How many segments do chelicerates have?
2: cephalothorax and posterior abdomen
147
What is a species of marine cheliceriforme?
Horseshoe crab
148
Where do all walking and feeding appendages occur on chelicerates?
cephalothorax
149
How many paired appendages do chelicerates have?
4 paired walking appendages, pedipalps = 6 appendages on cephalothorax
150
Do chelicerates have open or closed circulatory systems?
Open circulatory system, with book lungs through which hemolymph flows for gas exchange
151
For arachnids, what is the chelicera used for?
introducing venom into their prey
152
How many pairs of antenna do myriopods have?
1
153
How many feeding appendages do myriapods have?
1) Mandibles
2) Maxillae (First Pair)
3) Maxillae (Second Pair) or Labium
4) Centipedes only: Maxillipeds (Poison Claws)
154
How many pairs of legs do millipedes have per segment?
segments each one with two pairs of walking appendages
155
What do millipedes eat?
Millipedes eat decaying leaves and plant matter
156
What do centipedes eat?
they're carnivores
157
How many pairs of legs per segment in centipedes?
one pair of legs per trunk segment
158
What extra appendage on the foremost trunk segment do centipedes have?
poison claws on the foremost trunk segment that paralyze prey and aid in defence
159
Are insects more closely related to myriapods or crustaceans?
Recent evidence indicates that insects are more closely related to crustaceans than myriapods. And some lineages of crustaceans are more closely related to insects than other crustaceans.
160
What 2 sub-phylum create the pancrustacean clade?
insects and crustaceans form the pancrustacean clade
161
How many pairs of antenna do crustaceans have?
2 pairs
162
How many segments do crustaceans have?
2-3, but most have 3 = head, thorax, and abdomen
163
How many feeding appendages do crustaceans have?
3 = mandibles + other 2
164
Where do the walking appendages occur on crustaceans?
The thorax (or cephalothorax for some) includes walking appendages
165
What appendage can be featured on crustaceans' abdomen?
pairs of swimming appendages = swimmerets
166
What is the defining characteristic of copepods (crustacean)?
the smallest crustaceans (planktonic), have a cephalothorax and lack appendages on their abdomen (all on cephalothorax) AND Exoskeleton is so thin that it is transparent
167
What are 2 characteristics of isopods ad decapods?
1) hard exoskeletons
2) appendages on each of the three body segments
168
What is the exoskeleton of decapods hardened with?
In decapods (e.g. lobster, crab, shrimp) the exoskeleton is hardened with CaCO3.
169
Why are barnacles not a bivalve?
are sessile crustaceans with laterally compressed, calcified shells. Not a bivalve because of the paired appendages coming out of it.
170
What is the reason that demonstrate why hexapods are the most successful?
Hexapods (insects) are the most successful because of their coevolutionary connection with plants and an important group of arthropods = pollination services
171
How many body segments do hexapods have?
3 = head, thorax, abdomen
172
How many antenna do hexapods have?
1 pair of antennae
173
How many legs do hexapods have and on what segment?
three pairs of legs on thorax. Unlike crustaceans, there are no appendages on the abdomen
174
What systems do hexapods have that are the result of hox genes?
1) open circulatory system
2) respiratory system
3) other complex organ systems = Malpighian Tubules (excretory organs in most insects)
175
Compared to most other invertebrate phyla, what system is the most complex in hexapods?
Compared to other invertebrate phyla, they have the most complex respiratory system
176
True or false: all hexapods have wings
FALSE: not all hexapods have wings
177
How many pairs of wings do most groups of insects have?
thorax includes two pairs of wings
178
The wings are an extension of what?
The wings are an extension of the cuticle
179
True or false: hexapods aren't the only invertebrates capable of flight?
FALSE: hexapods ARE the only invertebrates capable of flight
180
How did hexapods help plants?
Flight enabled cross-pollination and increase the genetic variation in plants
181
What are the 6 different groups of hexapods?
1) Beetles (two pairs: one thick and stiff; the other membranous) *think of ladybug
2) Flies and mosquitos (one pair; the other reduced and functions in balancing)
3) Bees, ants and wasps (two pairs of membranous wings)
4) Butterflies and moths (two pairs covered in tiny scales)
5) True bugs (two pairs: one leathery, the other membranous)
6) Grasshoppers and crickets (two pairs: one leathery, the other membranous)
182
What is the definition of a chordate?
Chordates are bilaterally symmetrical deuterostomes with segmented bodies
183
What is the sister lineage of echinoderms?
Chordates are a sister lineage to echinoderms but have evolved separately for at least 500 million years
184
How many groups of vertebrates and invertebrates do chordates include?
Chordates include all vertebrates and two groups of invertebrates.
185
What are vertebrates?
Vertebrates are chordates that have a backbone.
186
What are gnathostomes?
Gnathostomes are vertebrates that have jaws.
187
What does gnatho mean?
Jaw
188
What are Osteichthyans?
Osteichthyans are gnathostomes that have calcified bones.
189
What are terapods?
Tetrapods are osteichthyans that have limbs.
190
What are amniotes?
Amniotes are tetrapods that have a terrestrially adapted egg.
191
What are mammals?
Mammals are amniotes that have hair and produce milk.
192
What are the 4 derived characteristics of chordates?
1) Notochord
2) Dorsal, hollow nerve cord
3) Pharyngeal slits and arches
4) Muscular, post-anal tail
193
Which organism is the only one to have these traits be visible during adulthood?
Lancelets
194
What is the notochord?
a longitudinal, flexible rod between the digestive tube (alimentary canal) and nerve cord
195
What is the function of the notochord?
It provides mechanical support (flexibility, but still rigid) throughout most of the length of a chordate embryo.
196
In humans, what are the remnants of the embryonic notochord in adults?
In humans, it is reduced to the intervertebral disks (IVD) (23 of them, made of cartilage) that cushion the vertebrae.
197
What is the function of the intervertebral disks (IVD)?
IVD gives the spine flexibility without sacrificing strength. Only thing that remains from the notochord
198
What does the nerve cord of chordate embryos develop from?
The nerve cord of chordate embryos develops from a plate of ectoderm that rolls into a hollow tube dorsal to the notochord.
199
What does the nerve cord develop into?
The nerve cord develops into the central nervous system: the brain and spinal cord.
200
What are the grooves in the pharynx called?
pharyngeal pouches/slits
201
when do pharyngeal pouches open to the outside of the body?
pharyngeal pouches eventually open to the outside of the body when the endoderm (lining the pharynx) meets the ectoderm (lining the outside of the embryo) and these openings create slits
202
What is the function of the slits that occur in the openings of the pharyngeal pouches?
The slits function in suspension feeding and gas exchange (the gills)
203
In tetrapods, the pouches develop into something else, what is it?
In tetrapods, the pouches develop into parts of the ear, head, and neck
204
Which pharyngeal pouch, in humans, turns into a tube that becomes a part of the ear?
first pouch (pharyngeal cleft)
205
Where do the tail in chordates occur?
Chordates have a tail posterior to the anus
206
True or false: In non-chordates, the digestive tract extends the entire length of the animal, but the digestive tract doesn’t run the entire length of the animal in chordates.
TRUE
207
What 2 things does the tail contain?
1) skeletal elements
2) muscles
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What is the function of the tail in many aquatic species?
It provides propelling force in many aquatic species
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What were lancelets named afor?
Named for their bladelike shape.
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What are the 2 groups in invertebrate chordates?
Lancelets and tunicates
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How does water move in and out of the lancelet?
Water enters the mouth and exits through hundreds of pharyngeal slits. Water accumulates in the atrium and expelled through the atriopore.
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What functions in filter feeding in lancelets?
pharyngeal slits
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How does gas exchange occur in lancelets?
Gas exchange occurs epidermally = through the surface of the body.
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When do tunicates showcase their chordate features?
only during the larval stage
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What happens to the pharynx in tunicate adults?
as an adult, the basket-like slitted pharynx enlarges significantly.
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How does water flow in and out of tunicates?
Water entering from the prominent incurrent siphon passes through the gill slits and accumulates in the atrium. From there, it is expelled by the excurrent syphon.
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What part in tunicates functions in filter feeding and gas exchange?
The pharynx functions in filter feeding and gas exchange.
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True or false: Tunicates are highly diverged and have more Hox genes than any other chordate.
FALSE: Tunicates are highly diverged and have FEWER Hox genes than any other chordate.
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What does the pharynx resemble in tunicates?
Pharynx with numerous slits looks like gauze
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What does Tetraploidization mean?
2 separate duplications
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How many sets of hox genes do vertebrates have?
Vertebrates have two or more sets of Hox genes
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How many sets of hox genes do invertebrate animals have (tunicates and lancelets)?
lancelets and tunicates have only one cluster. This has enabled the innovation of several characters that are unique to vertebrates
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What type of cells differentiate into anatomical structures unique to vertebrates?
Neural crest cells emerged near the margins of the neural fold. These cells migrate to other parts of the embryo and differentiate into anatomical structures that are unique to vertebrates. Neural crest cells form the vertebrae and parts of the skull and is only seen in vertebrates.
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What are the 4 derived characteristics of vertebrates?
1) Vertebrae enclosing a spinal cord
2) An elaborate anterior skull enclosing a brain
3) Fin rays, in the aquatic forms
4) Chambered ventral heart; split between oxygen rich and oxygen poor blood.
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What are lampreys and hagfish known as?
cyclostomes
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What are cyclostomes?
jawless vertebrates with mouths lined with keratin derived teeth
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What is a visibly defining characteristic of lampreys?
In lampreys, the pharynx is perforated by seven circular gill slits
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How do lampreys ventilate their gills?
lampreys use muscle tissue around the gills to move water in and out of the gills for ventilation
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How do lampreys parasitize other fish and what modification needed to occur in order for them to breathe and eat at the same time?
lampreys parasitize other fish by stitching their rasping circular mouths to their prey and slowly digesting their tissues by secreting urea, thus they require muscle tissue around the gills to move water in and out while they eat
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What is water sucked in from in hagfish?
Hagfish have a single nostril through which water is sucked in before flowing out through the gill slits (Internal gills)
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How does gas exchange occur in hagfish when they're buried in sediment?
dense network of capillaries beneath the skin that function in gas exchange when the animal is buried in sediment
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What is a distinct feature of hagfish?
series of paired slime glands on either side of its body
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What does the slime of hagfish do to predators
Hagfish can release copious amounts of slime when threatened by predators; the slime coats the predator along with its gills making gas exchange difficult
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What does gnotho mean?
jaw
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jaws are hypothesized to have evolved from what?
hypothesized to have evolved from skeletal supports of the pharyngeal region
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What are gnathostomes?
vertebrates with jaws
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Teeth also made jaws more efficient, how?
food can now be mechanically and chemically digested in the oral cavity
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What were the first jawed vertebrates?
Chondrichthyans
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what 3 organisms are included in chondrichthyans?
sharks, rays, and skates
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What is chondrichthyan" is derived from?
“chondrocyte”, the principal type of cell in cartilage
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What part of the chondrichthyan is mineralized (bone)?
Only their teeth and jaws are mineralized; the rest of the skeleton is made of cartilage.
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How do sharks get water to enter?
In sharks, water enters the mouth with brute force (they are fast, powerful swimmers) and exits through five gill slits (slits in the pharynx)
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How many gill slits do sharks have?
5
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What do chondrichthyans have to help them draw water into the pharynx when they aren't swimming?
spiracle
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How do chondrichthyans make up for the lack of a swim bladder?
The challenge of maintaining buoyancy in sharks is therefore met by having copious amounts of fat tissue (fat is significantly less dense than muscle tissue)
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What are Osteichthyans?
All other vertebrates are osteichthyans– animals with mineralized bones. The aquatic members of the clade include ray- and lobe-finned fishes
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What is the defining visible feature of ray-finned fish?
have pectoral and pelvic fins made of a thin web of skin covering radially extending bones
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How does water flow in and out of bony fish?
These bony fish breathe by drawing water through the mouth and pharynx before flowing out through hundreds of external gill filaments (all previous fish had internal gills) lining the branchial arches (the arches that separate the slits)
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How many pairs of arches do bony fish have and what is each one lined with?
Bony fish have 4 pairs of such arches, each one lined with two rows of gill filaments
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What are the gills protected and aided by in bony fish?
protected and aided by an operculum –a bony flap that helps to ventilate the gills
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What are the 2 pumps for gas exchange in bony fish?
mouth and operculum
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What is a defining characteristic of lobe-finned fish?
Lobe-fins have rod-shaped bones surrounded by muscle on pelvic and pectoral fins that they use to swim and “walk” underwater across the substrate
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What are the 2 surviving lineages of lobe-finned fish?
coelacanths (2 spp.) and lungfishes (6 spp)
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What kind of respiration occurs in lungfish?
bimodal respiration system using both lungs and gills for gas exchange.
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What are the lungs in lungfish modified from?
The lungs = modified swim bladders
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The lungfish are the closest living relatives to what?
Lungfish are the closest living relatives to the tetrapods
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What are the 5 derived characters of tetrapods?
1) Four limbs, and feet with digits
2) A neck, which allows separate movement of the head
3) Fusion of the pelvic girdle to the backbone
4) No gills (except some aquatic species)
5) Ears for detecting airborne sounds
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What are salamanders?
Salamanders are amphibians with tails
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Where do amphibian eggs and larvae develo?
Amphibian eggs develop in water and the larvae of most species remain aquatic before metamorphosing into the adult form and moving on land
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What aids frogs/toads with movement on land?
Frogs/toads lack tails but have powerful hind legs for locomotion on land
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What are caecilians and what do they look like?
Amphibians and they look like worms, but they are limbless amphibians
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What are the key external features of the caecilian?
Key external features of their true taxon are their face and jaw
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What is caecilian anatomy adapted for?
burrowing
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How does respiration and gas exchange occur in amphibians?
Subcutaneously with capillaries under skin and lungs where air is forced into the lungs when the floor of the buccal cavity is raised.
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What are amniotes?
Amniotes are tetrapods with a terrestrial adapted egg
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What 2 classes of animals do amniotes include?
Amniotes include the reptilian and mammalian class
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What animals do reptiles include?
The reptiles include the tuataras, lizards, snakes, turtles, crocodilians, birds, and some extinct groups (dinosaurs). Most reptiles lay shelled eggs on land.
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What are the major adaptations that occurred in birds so that they are adapted to flight?
Major adaptations are wings, feathers, and porous bones (brittle because they need to be light enough to fly)
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What shape of ears do birds have?
Birds have funnel-shaped ears that lead to the middle ear containing a surprisingly large diversity of bone shapes for transmitting sound
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How many species of mammals are there?
Mammals represented by more than 5,300 species
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What are the 5 derived characteristics of mammals?
1) Mammary glands, which produce milk
2) Hair
3) A high metabolic rate, due to endothermy. Meaning you need a very good heart to pump blood efficiently to enable rapid oxygenation of your muscle tissue and to preserve heat
4) A larger brain than other vertebrates of equivalent size
5) Differentiated teeth
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What does differentiated teeth in mammals suggest?
Varied diet means you’re exploiting the environment so your brain is ever growing. Diet complexity/variety and IQ related
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All molluscs have an open circulatory system except one group, which is it?
cephalopods
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Which group within molluscs is the most speciose?
gastropods = 80% of all molluscs
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What are 4 examples of gastropods?
1) snails
2) slugs
3) limpets
4) nudibranchs (sea slugs)
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The arthropod phylum is in what clade and same clade as what other phylum?
Arthropods are in the clade ecdysozoan with nematodes
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What are the 3 lineages in chelicerates?
1) horseshoe crabs
2) arachnids
3) sea spiders
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What are the 2 lineages in myriapods?
1) millipedes
2) centipedes
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What are the 5 lineages in pancrustaceans?
1) isopods
2) decapods
3) copepods
4) barnacles
5) hexapods
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What are some modern examples of cheliciforms?
mites, ticks, scorpions, and spiders
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What appendage in chelicerates is posterior to the most anterior appendage which is the chelicera?
pedipalps
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What are 3 examples of decapods?
lobsters, crabs, and shrimp
