34 Flashcards
vertebrates
derives from the name vertebrate- series of bones that make up the vertebral column
chordates
bilateral animals and belong to clade deuterostomia
notochord
longitudinal flexible rod located between the digestive tube and the nerve cord
Four key characters of chordates:
– Notochord
– Dorsal, hollow nerve cord
– Pharyngeal slits or clefts
– Muscular, post-anal tail
Lancelets (subphylum Cephalochordata)
are named for their bladelike shape
• They are marine suspension
feeders that retain characteristics of the chordate body plan as adults
Vertebrates have the following derived characters:
– Vertebrae enclosing a spinal cord
– An elaborate skull
– Fin rays, in the aquatic forms
• …but, the earliest vertebrates lacked jaws (and some even lack a backbone)
Chondrichthyes Reproduction
Exhibit Internal Fertilization
the evolution of tetrapods
One of the most significant events in vertebrate history was when the fins of some lobe-fins evolved into the limbs and feet of tetrapods
Derived traits of tetrapods
– Four limbs, and feet with digits
– A neck, which allows separate
movement of the head
– Fusion of the pelvic girdle to the backbone
– The absence of gills (except some aquatic species)
– Ears for detecting airborne sounds
Derived Characters of Birds
- Many characters of birds are adaptations that facilitate flight
- The major adaptation is wings with keratin feathers
- Other adaptations include lack of a urinary bladder, females with only one ovary, small gonads, and loss of teeth
3 groups of terrestrial vertebrates:
amphibians, reptiles, mammals
most basal group of living chordates are
the lancelets
____ are more closely related to other chordates than are lancelets
tunicates
the chordate characteristic of tunicates are most apparent during the ____
larval stage
vertebrates are chordates that
have a backbone
An animal has segments, bilateral symmetry, pharyngeal gill slits, a post-anal tail, and deuterostomic development. It must be a member of the phylum ____________.
Chordata
A ____ is a chordate but not a vertebrate.
lancelet
It appears that cephalochordates evolved by a process that involved the development of mature reproductive organs in an otherwise juvenile form. This evolutionary process is called _____.
paedogenesis
Which of the following pairs is NOT matched correctly?
Gnathostomata … hagfish
A lamprey, a shark, a lizard, and a rabbit share all the following characteristics EXCEPT _____.
hinged jaws
A feature of bony fish not found in sharks is(are) _____.
a swim bladder
The gill flap, or operculum, was an important adaptation for fish because it helps with _____.
maintaining a supply of oxygen
The first vertebrates to live on land were _____.
amphibians
The development that freed vertebrates from water for reproduction and allowed them to radiate into diverse terrestrial environments was the _____.
amniotic egg
In contrast to the traditional grouping of reptiles, cladistic analysis indicates that Reptilia is not a monophyletic group and that _____.
birds are more closely related to crocodiles than either is to turtles
Which of the following is NOT shared by extant birds and extant reptiles?
endothermic metabolism
All mammals _____.
nourish their offspring through mammary glands
Which one of the following characteristics appears in mammals, but not in reptiles?
a lower jaw consisting of a single bone
The opossum is an example of a(n) __________ mammal.
marsupial
Eutherians are viviparous, which means that __________.
the young develop within the female”s body
Whales and dolphins belong to the order _____.
Cetacea
The two major groups of primates are _____.
prosimians and anthropoids
If you were to observe a monkey in a zoo, which characteristic would indicate a New World origin for that monkey species?
use of the tail to hang from a tree limb
The earliest primates were most similar to modern _____.
arboreal prosimians
Humans and the slender loris, a prosimian, share many traits that probably evolved in our early primate ancestors, including _____.
opposable thumbs
Humans, apes, and monkeys are classified together as _____.
anthropoids
The modern genera of apes are ______.
gibbons, orangutans, gorillas, chimpanzees, and bonobos
Primates are distinguished from other mammals by __________.
opposable thumbs, nails, and good depth perception
Scientists who study human evolution are called __________.
paleoanthropologists
Which of the following traits distinguishes hominids from apes?
bipedalism (upright walking)
__________ arose very early in hominid evolution; __________ evolved more recently.
Upright posture … large brains
The human skull differs from the gorilla skull in that the human skull has __________.
a larger brain case
Bipedalism is associated first with what hominid?
australopithecines, such as Lucy
The first hominid known to make tools is(was) _____.
Homo habilis
What was the earliest hominid to have an enlarged brain (relative to body size)?
Homo habilis
Homo erectus __________.
followed H. habilis
Which of the following correctly lists probable ancestors of modern humans from the oldest to the most recent?
Australopithecus, Homo habilis, Homo erectus
Some anthropologists think that modern races of Homo sapiens evolved from separate populations of archaic H. sapiens in different geographic areas. How, then, do proponents of this multiregional hypothesis explain the great degree of genetic similarity among modern humans?
The ancestral Homo erectus originally came from Africa.
The multiregional and replacement hypotheses for the origin of modern humans agree that _____.
Homo erectus had an African origin
Which one of the following statements best fits the replacement hypothesis about the origin of modern humans?
Homo sapiens evolved from H. erectus in Africa and then migrated elsewhere.
vertebrates are a subphylum in
phylum chordata
Two groups of invertebrate deuterostomes, ______ and _______ , are more closely related to vertebrates than to other invertebrates
the urochordates and cephalochordates
_____ most resemble chordates during their larval stage, which may last only a few minutes
Tunicates
Hagfishes (Myxini)
jawless vertebrates that have a cartilaginous skull, reduced vertebrae, and a flexible rod of cartilage derived from the notochord
• They have a small brain, eyes, ears, and tooth-like formations
• Hagfishes are marine; most are bottom-dwelling scavengers
Lampreys (Petromyzontida)
are parasites that feed by clamping their mouth onto a live fish
• They inhabit various marine and freshwater habitats
• They have cartilaginous segments surrounding the notochord and arching partly over the nerve cord
_____ are vertebrates with jaws
Gnathostomes
______ have a skeleton composed primarily of cartilage
Chondrichthyes
sharks have a
Lateral line system
All fishes rely heavily on the _______
lateral line system: a series of pores and canals lined with cells (neuromasts) that are specialized to detect vibrations.
Chondrichthyes Reproduction (sharks, etc)
Exhibit Internal Fertilization
Ray-finned fishes are in which class
Class Actinopterygii
Tetrapods have some specific adaptations:
– Four limbs, and feet with digits
– A neck, which allows separate
movement of the head
– Fusion of the pelvic girdle to the backbone
– The absence of gills (except some aquatic species)
– Ears for detecting airborne sounds
Class Reptilia are
Ectotherms
Class Aves are part of what clade
reptilia
Derived Characters of Birds
- Many characters of birds are adaptations that facilitate flight •The major adaptation is wings with keratin feathers
- Other adaptations include lack of a urinary bladder, females with only one ovary, small gonads, and loss of teeth
Mammals have
– A high metabolic rate, due to endothermy
– Hair
– Mammary glands, which produce milk
– A larger brain than other vertebrates of equivalent size
– Differentiated teeth
-fur
Monotremes
a small group of egg-laying mammals consisting of echidnas and the platypus
eutherians
have a more complex placenta. Young eutherians complete their embryonic development within a uterus, joined to the mother by the placenta
(humans)
Marsupials
include opossums, kangaroos, and koalas. The embryo develops within a placenta in the mother’s uterus
A marsupial is born very early in its development. It completes its embryonic development while nursing in a maternal pouch called a marsupium
derived characters of primates:
– A large brain and short jaws
– Forward-looking eyes close together on the face, providing depth perception
– Complex social behavior and parental care
– A fully opposable thumb (in monkeys and apes)
Humans are mammals with a
large brain and bipedal locomotion
A number of characters distinguish humans from other apes:
– Upright posture and bipedal locomotion – Larger brains – Language capabilities and symbolic thought – The manufacture and use of complex tools – Shortened jaw – Shorter digestive tract
hominins
originated in africa - had small brain
homo erectus
first hominin to leave africa
vertebrates and tunicates share
a notochord, dorsal and hollow nerve cord
living vertebrates can be divided into two major clades. what are they are?
the cyclostomes and gnathostomes
unlike eutherians, both monotremes and marsupials
have some embryonic development outside of uterus
which clade does not include humans
diapsids
as hominins diverged from other primates, which of the following appeared first?
bipedal locomotion
which of the following could be considered the most recent common ancestor of living tetrapods?
a sturdy, finned shallow water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates
shark eggs are fertilized _____
internally
oviparous
lay eggs that hatch outside of mothers body
ovoviviparous
retain fertilized eggs
viviparous
young develop in uterus and receive nutrients through placenta
_____ are most basal group of tetrapods
Amphibians
Why are birds grouped into the clade with the dinosaurs?
o Amniotic egg
o Tetrapods – reduced forelimbs
o Bones are hallow
o Birds are more closely related to dinosaurs because of modified forelimbs and feathers
True or False: All Chordates are vertebrates. Explain with examples.
False.
all vertebrates are chordates but all chordates are not vertebrates
examples of non vertebrates are sea squirts and lancelets
what is the name of the clade that includes jawed vertebrates?
gnathostomes
name two subphyla within chordata that lack vertebral column
Urochordata and Cephalochordata
what are in subphylum chelicerata? and what phylum is this in?
horseshoe crabs, spiders, ticks, scorpions
Arthropoda
why phylum is pancrustacea in?
arthropoda
what is in phylum echinodermata
sea stars, sea urchin
what phylum and subphylum are lancelets in?
phylum chordata and cephalochordata
what are tunicates (sea squirts in)
phylum chordata and urochordata
what are jawless fishes
Clade Cyclostomes – jawless fishes
Class Myxini – Hagfishes
Petromyzontida – Lampreys
what are the Cartilaginous fishes
class Chondrichthyes
what superclass are the bony fishes
superclass Osteichthyes
what are the clades in mammalia?
- Clade Monotremes – platypus, echidnas
- Clade Marsupials – opossums, kangaroos, koalas
- Clade Eutherians – placental mammals
a. Order Primates
