Chapter 34 Flashcards
Vertebrates
animals with vertebrae, the series of bones that make up the backbone
One lineage of vertebrates colonized land ______ million years ago and gave rise to modern __________, _________, and _________
365; amphibians; reptiles; mammals
Chordates
phylum Chordata; bilateral animals that belong to the clade Deuterostomia
Chordates comprise all __________ and two groups of invertebrates, the __________ and ___________
vertebrates; urochordates; cephalochordates
Four key characters of chordates
1) notochord
2) Dorsal, hollow nerve cord
3) Pharyngeal slits or clefts
4) Muscular, post-anal tail
notochord
a longitudinal, flexible rod between the digestive tube and nerve cord; provides skeletal support
The nerve cord
develops from a plate of ectoderm that rolls into a tube dorsal to the notochord
pharyngeal clefts
grooves in the pharynx of most chordates that develop into slits that open to the outside of the body
Functions of pharyngeal slits
- Suspension-feeding structures in many invertebrate chordates
- Gas exchange in vertebrates (except in tetrapods)
- develop into parts of the ear, head, and neck in tetrapods
Lancelets
Cephalochardata; named for their bladelike shape; marine suspension feeder that retain characteristics of the chordate body plan as adults
Tunicates
Urochordata; closest relative to lancelets; mostly resemble chordates in their larva stage (only a few minutes)
T/F: Tunicates are parasitic
False; tunicates draw in water through an incurrent siphon and filter feed
The same _________ that organize the vertebrate brain are expressed in the __________ simple nerve cord tip
Hox genes; lancelet’s
T/F: Vertebrates have two or more sets of Hox genes whereas lancelets and tunicates have only one
True
Vertebrates have the following derived characters
- Neural crest
- Vertebrae enclosing a spinal cord
- An elaborate skull
- Fin rays, in the aquatic forms
Fossil evidence shows that the earliest vertebrates lacked _____
jaws
Only two lineages of jawless vertebrates remain today: __________ and __________
hagfishes; lampreys
T/F: hagfishes and lampreys lack a backbone
True
Gnathostomes
vertebrates that have jaws
Common gnathostome characteristics
- Genome duplication (including Hox genes)
- An enlarged forebrain associated with enhanced smell and vision
- lateral line system , which is sensitive to movement, vibrations, and pressure (in aquatic gnathostomes)
Chondrichthyans
have skeleton composed primarily of cartilage; includes sharks, rays, and skates
T/F: the smallest sharks are suspension feeders, but most are carnivores
False; the largest sharks are suspension feeders
T/F: Sharks and some other animals have two jaws, the oral jaws and pharyngeal jaws
True
Shark eggs are fertilized internally but embryos can develop in three different ways:
1) Oviparous
2) Ovoviviparous
3) Viviparous
Oviparous
Eggs hatch outside the mother’s body
Ovoviviparous
The embryo develops within the uterus and is nourished by the egg yolk
Viviparous
The embryo develops within the uterus and is nourished through a yolk sac placenta from the mother’s blood
cloaca
the common place where the reproductive tract, excretory system, and digestive tract empty
Osteichthyans
vertebrates with bony endoskeletons; include bony fish and tetrapods
Actinopterygii
the ray-finned fishes; include nearly all the familiar aquatic osteichthyans
Lobe-fins
Have muscular pelvic and pectoral fins that they use to swim and “walk”; include coelacanths, lungfishes, and tetrapods
Specific adaptations of Tetrapods
- Four limbs, and feet with digits
- A neck
- Fusion of the pelvic girdle to the backbone
- The absence of gills (except some aquatic species)
- Ears for detecting airborne sounds
three amphibian clades
- Urodela (salamanders)
- Anura (frogs)
- Apoda (caecilians)
Salamanders
amphibians with tails; some are aquatic while others live on land
Paedomorphosis
the retention of juvenile features in sexually mature organisms; common aquatic species
Anurans
Frogs; lack tails and have powerful hind legs for locomotion
Toads
frogs with leathery skin
Tadpoles
herbivores that lack legs, but legs, lungs. external eardrums, and adaptations for carnivore may all arise during metamorphosis
Apoda
Caecilians; legless, nearly blind and resemble earthworms
T/F: in caecilians, the absence of legs is a primary adaptation
False; secondary
Amniotes
A group of tetrapods; living members include reptiles, birds, and mammals
Reptiles
have scales, lay shelled eggs on land
Ectothermic
Cold-blooded; rely on external sources of heat to regulate their body temperature
Endothermic
Warm-blooded; dependent on or capable of the internal generation of heat
Theropods
Bipedal carnivores; the group from which birds come
Snakes
legless lepidosaurs; canivorous
Snake adaptations to help feeding
- Chemical sensors
- Heat-detecting organs
- Vemon
- Loosely articulated jawbones and elastic skin
Derived characters of Birds
- Characters of birds are adaptations that facilitate flight
- wings with keratin feathers
- lack of a unirnary bladder, females with only one ovary, small gonads, and loss of teeth
Adaptations unique to mammals
- Mammary glands (produce milk)
- Hair
- A high metabolic rate (endothermy)
- A larger brain than other vertebrates of equivalent size
- Differentiated teeth
Monotremes
small group of egg-laying mammals consisting of echidnas and the platypus
Primitive monotreme features
- Egg-laying (oviparity)
- Cloaca
- Egg tooth
- Primitive skeletal features
Marsupials
Animals born in very early in its development; the embryo develops within a placenta in the mother’s uterus; short gestation, long lactation
Eutherians
placental mammals; complete embryonic development within a uterus joined to the mother’s placenta
Primates
lemurs, tarsiers, monkeys, and apes; have hands and feet adapted for grasping, and flat nails
Derived characters of primates
- a large brain and short jaw
- Forward-looking eyes close together
- complex social behavior and parental care
- fully opposable thumbs
Three main groups of primates
- Lemurs, lorises, and bush babies
- Tarsiers
- Anthropoids (monkeys and apes)
Curiosity
a quality related to inquisitive thinking and is evident in humans and animals
Derived characters of humans
- upright posture and bipedal locomotion
- Larger brains capable of language, symbolic thought, art, and the manufacturing of complex tools
- reduced jawbones and jaw muscles
- shorter digestive tract
Paleoanthropology
The study of human origins
Hominins
more closely related to humans than to chimpanzees
Homo ergaster
the first fully bipedal, large-brained hominid
