Lecture Exam #4 Ch. 34 Flashcards
where do the animals called vertebrates get their name from?
vertebrae, the series of bones that make up the backbone
what modern animals did vertebrates give rise to? (3) (ARM)
1) amphibians
2) reptiles (including birds)
3) mammals
how many vertebrates are there on Earth and what do they include?
57,000 and they include some of the largest organisms
what do verterbrates have?
great disparity with a wide range of differences within the group
what do chordates have?
a notochord and a dorsal, hollow nerve cord
what type of animals are chordates and what clade do they belong to?
they are bilaterian and they belong to the clade konwn as dueterostomia
what does chordates comprise?
1) all vertebrates
2) group of invertebrates, the urochordates and cephalochordates
what do all chordates share?
a set of derived characteristics
what do some species of chordates have?
some of the derived traits only during embryonic development
4 key characters of chordates (NDPM)
1) notochord
2) dorsal, hollow nerve cord
3) pharyngeal slits or clefts
4) muscular, post-anal tail
a longitudinal, flexible rod between the digestive tube and nerve cord
notochord
what does the notochord provide?
skeletal support throughout most of the length of the chordate
in most verterbrates what devleops
a more complex, jointed skeletal and the adult retains only the remnants of the embroynoic notochord
what does the nerve cord of a chordate embryo develop from?
a plate of ectoderm that rolls into a tube dorsal to the notochord
what does the nerve cord develop into?
the central nervous system (the brain and the spinal cord)
found in most chordates, grooves in the pharynx that develop into slits that open to the outside of the body
pharyngeal clefts
functions of the pharyngeal slits (3) (SGD)
1) suspension- feeding structures in many inveterbrate chordates
2) gas exchange in vertebrates (except vertebrates with limbs, the tetrapods)
3) develop into parts of the ear, head and neck in tetrapods
in many chordate species what is greatly reduced during embryonic development?
the tail
what does the tail provide in many aquatic animals?
propelling force
what are lancelets (cephalochordata) named for?
their bladelike shape
what type of feeders are lancelets?
marine suspension feeders
what do lancelets retain as adults?
the characteristics of the chordate body plan
what is more closely related to chordates than lancelets?
tunicates
when does tunicates most resemble chordates?
during their larval stage (which may only last a few min)
what does a tunicate do as an adult?
draws in water through an incurrent siphon, filtering food particles
what do tunicates or “sea squirts” do when attacked?
shoot water through their excurrent siphon
what may have ancestral chordates resembled?
lancelets
where are the same hox genes that organize the vertebrate brain expressed in as well
the lancelets’s simple nerve cord tip
what does the sequencing of the tunicate genome indicate? (2) (GG)
1) genes associated with the heart and thyroid are common to all chordates
2) genes associated with transmission of nerve impulses are unique to vertebrates
what two essential tasks does the skeletal system and nervous system allow vertebraes to do? (2) (CE)
1) capture food
2) evade predators
how many sets of hox genes does vertebrates have?
two or more
how many hox genes do lancelets and tunicates have?
only one cluster
derived characteristics of vertebrates (VEF) (3)
1) vertebrae enclosing a spinal cord
2) an elaborate skull
3) fin rays, in aquatic forms
what does fossil evidence show that the earliest vertebrates lacked?
jaws
what two lineage of jawless vertebrates remain?
hagfishes and lampreys
what do members of hagfishes and lampreys lack?
a backbone
what indicates that hagfishes and lampreys are vertebrates?
the presence of rudimentary vertebrae and the results of phylogentic analysis
what clade of living jawless vertebrates do the hagfishes and and lampreys form together?
cyclostomes
what much larger clade do vertebrates with jaws make up?
gnathostomes
characterisitcs of hagfishes (4) (JCRF)
1) jawless vertebrates
2) have a carliganious skull
3) reduced vertebrae
4) flexible rod of cartlage derived from the notochord
what small features do hagfishes have?
small brain, eyes, ears and tooth-like formations
what type of animals are hagfishes?
marine, most are bottom-dwelling scavengers
how do the parasites, lampreys (Petromyzontida) eat?
ones that feed by clamping their mouth onto live fish
what type of environments do lampreys inhabit?
various marine and freshwater habitats
what does lampreys have?
cartilaginous segments surrounding the notochord and acrhing partly over the nerve cord
what documents the transitions to craniates?
fossils from the cambrian explosion
what were the most primitive of the fossils from the Cambrian evolution?
those of the 3-cm-long Haikouella
characteristics of the Haikouella (4) (WEMN)
1) well-formed brain,
2) eyes
3) muscular segments
4) no skull or ear organs
what were among the earliest verterbrates in the fossil record, dating from 500 to 200 million years ago?
conodonts
what did condodonts have?
mineralized skeletal elements in their mouth and pharynx
what was common the fossil record of condodonts?
fossilized dental elements
what are other groups of jawless vertebrates armored with?
defensive plates of bone on their skin
what did minerlization of bone and teeth appear to have originated with?
vertebrate mouthparts
what became fully mineralized much later?
the vertebrate endoskeleton
today what outnumbers jawless vertebrates?
jawed vertebrates, gnathostomes
what do gnathostomes include? (6) (SRLARM)
1) sharks and their relatives
2) ray-finned fishes
3) lobe-finned fisehs
4) amphibians
5) reptiles (including birds)
6) mammals
what are gnathostomes named for?
their jaws
what does the jaws with the help of teeth in gnasthostomes help do?
grip food items firmly and slice them
what are the jaws of gnasthostomes hypothesized to have evolved by?
modificiation of skeletal rods that supported pharyngeal (gill) slits s
other characteristics common to gnathostomes (3) (GEA)
1) genome duplication including duplication of hox genes
2) an enlarged forebrain associated with enhanced smell and vision
3) in aquaitc gnathostomes the lateral line system, which is sensitive to vibration
what are the earliest gnasthostomes in the fossil record that appeared 440 million years ago?
an extinct lineage of armored verterbrates called placoderms
what is another group of jawed vertebrates called that radiated during the Silurian and Devonian periods (444 to 359 million years ago)?
acanthodians
what are three lineages of jawed vertebrates that survive today? (3) (CRL)
1) chondrichthyans
2) rayed-finned fisehs
3) lobe-fins
what do chondrichthyans include?
sharks, rays and their relatives
what do chondrichthyans have?
a skeleton composed primarily of cartlage
what does the largest and most diverse group of chdonrichtyans include?
sharks, rays and skates
what is a second subclass of chondorichythans composed of?
a few dozen species of ratfishes or chimaeras
what type of bodies do sharks have and what type of swimmers are they?
a streamlined body and are swift swimmers
what type of feeders are the largest sharks and what are most of them?
suspension feeders but most are carnivores
what type of digestive system do sharks have?
a short digestive tract with a ridge called the sprial valve
what does the spiral valve do for sharks’ digestive system?
increases the digestive surface area
what type of acute senses do sharks have?
sights, smell and the ability to detect electrical fields from nearby animals
how are sharks eggs fertilized?
internally but embryos can develop in different ways
different ways that embryos can develop in sharks (3) (OOV)
1) oviparous
2) ovoviviparous
3) vivparous
eggs hatch outside the mother’s body
oviparous
the embryo develops within the uterus and is nourised by the egg yolk
ovoviparous
the embryo develops within the uterus and is nourished through a yolk sac placenta from the mother’s blood
vivparous
in sharks, what does the reproductive tracts, excretory system and digestive tract empty into?
a common cloaca
today, what are sharks severly threatened by?
overfishing (pacific population plummeted upto 95%)
what clade of gnasthostomes does the vast majority of vertebrates belong to?
osteichthyes
what do nearly all living osteichthyes have?
a bony endoskeleton
what does osteichthyans include?
bony fishes and tetrapods
what are aqautic osteichthyans?
vertebrates we informally call fishes
how do most fishes breath?
by drawing water over gills protected by an operculum
how do fishes control their buoyancy?
with an air sac known as a swim bladder
what do fishes have?
a lateral line system
what type of embryo development do most fishes have?
oviparous but some have internal fertilization and birthing
what does actinopterygii the ray-finned fishes include?
nearly all the familiar aquaitc osteichthyans
when did ray-finned fishes originate?
during the Silurian period
what are the fins of ray-finned fishes supported mainly by long, flexible rays modified for?
maneuvering, defense and other functions
what did industrial-scale fishing operations drive many ray-finned fish populations to do?
collapse
what are populations of ray-finned fishes also affected by and what does it change?
dams, and it changes water flow patters, affecting prey capture, migration and spawning
when did lobe-fins (sacropterygii) originate?
during the Silurian period
what do lobe-fins have and for what?
muscular pelvic and pectoral fins to swim and “walk” underwater across the substrate
what are the 3 lineages of lobe-fins that survive? (3) (CLT)
1) coelacanths
2) lungfishes
3) tetrapods
even though Coelacanths were thought to have become extinct 75 million years ago, what was caught?
a living coelacanth caught of the coast of South Africa in 1938
where are the living lungishes all found?
in the Southern Hemisphere
though gills are main organs for gas exhange in lungfishes what else can they do?
surface to gulp air into their lungs
what is the third surviving lineage of lobe-fins, tetrapods adapted to?
life on land
what are tetrapods?
gnathostomes that have limbs
what is one of the most significant events in vertebrate history?
when the fins of some lobe-fins evolved into the limbs and feet of tetrapods
specific adaptions of tetrapods (5) (FNFAE)
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) the absence of gills (except some aquatic species)
5) ears for detecting airborne sounds
what does the Tikaalik, nicknamed “fishapod” show about the origin of tetrapods?
both fish and tetrapod characteristics
what did the Tikaalik have? (4) (FRNF)
1) fins, gills, lungs, and scales
2) ribs to breathe air and support its body
3) a neck and shoulders
4) fins with a bone pattern of a tetrapod limb
what could tiktaalik most likely do?
prop itself on its fins, but not walk
when did the first tetrapod appear?
365 million years ago
what are amphibians represented by?
6,150 species in three clades
three clades of amphibians (3) (UAA)
1) urodela (salamanders)
2) anura (frogs)
3) apoda (caecillians)
what are salamanders (urodela)?
amphibians with tails
what type of animals are salamanders?
aquatic but others live on land as adults or throughout life
the retention of juvenile features in sexually mature organisms which is common in aquatic species
paedomophosis
what do frogs (anurans) lack and what do they have?
they lack tails and have powerful hind legs for locomotion on land
what are frogs with leathery skin called?
“toads”
characteristics of caecilians (apoda)
1) leggless
2) nearly blind
3) resemble earthworms
what is the absence of legs in caecilians?
a secondary adaption
what does amphibians mean and what does it refer to?
“both ways of life” and refers to the metamorphasis of an aquatic larva into a terrestrial adult
what are tadpoles?
herbivores that lack legs
what may arise during metamorphosis for tadpoles? (4) (LLEA)
1) legs
2) lungs
3) external eardrums
4) adaptions for carnivory
what is fertilization in most amphibians and what does it require?
external and eggs require a moist environment
where do males or females in some amphibians care for the eggs?
on their back, in their mouth or in their stomach
what has been happening to amphibian populations in recent decades?
they’ve been declining
what are the causes of the declining populations of amphibians in recent decades? (DHCP) (4)
1) a disease- causing chytrid fungus
2) habitat loss
3) climate change
4) pollution
what are amniotes?
tetrapods that have a terrestrially adapted egg
what do amniotes include?
reptiles (including birds) and mammals
what are amniotes named for?
the major derived character of the clade, the amniotic egg (contains membrains that protect the embryo)
what does the extraembryonic membrane include?(4) (ACYA)
1) amnion
2) chorion
3) yolk sac
4) allatois
what was the amniotic egg?
a key adaption to life on land
what do amniotic eggs of most reptiles and some mammals have?
a shell
what other terrestrial adapation do amniotes have? (2) (RA)
1) relatively impermeable skin
2) the ability to use the rib cage to ventilate the lungs
when did living amphibians and amniotes split from the common ancestor?
about 350 million years ago
what were early amniotes more tolerant of than the first tetrapod?
dry conditions
what were the earliest amniotes?
small predators with sharp teeth and long jaws
what does the reptile clade include? (7) (TLSTCBS)
1) tuataras
2) lizards
3) snakes
4) turtles
5) crocodilians,
6) birds
7) some extinct groups
what do reptiles have and what does it create?
scales that create a waterproof barrier
what do most reptiles do?
lay shelled eggs on land
what are most reptiles and what does that mean?
ectothermic, absorbs external heat as main source of body heat
what do ectotherms regulate body temp through?
behavioral adaptions
what are birds and what does that mean?
endothermic, capable of maintaining body temp through metabolism (like mammals)
what were the first major group of reptiles to emerge and what were they?
parareptiles, mostly large, stocky quadrupal herbirvores
as parareptiles were dwindling what were diversifying?
diapsids
what are the two main lineages of diapsids? (2) (LA)
1) lepidosaurs
2) archosaurs
what do lepidosaurs include? (4) (TLSE)
1) tutaras
2) lizards
3) snakes
4) extinct monosaurs
what do archosaurs include? (3) (CPD)
1) crodolians
2) pterosaurs
3) dinosaurs
what were the first tetrapods to exhibit flight?
pterosaurs
what did dinosaurs diversify into
a vast range of shapes and sizes
what did dinosaurs include from a group from which birds are descended?
theropods
what did fossil discoveries and research lead to the conclusion about dinosaurs?
that many of them were agile and fast moving
what else did paleontologists discover about dinosaurs?
signs of parental care among dinosaurs
what did some anatomical evidence support the hypothesis about signs of parental care among dinosaurs?
some were endotherms
when did dinosaurs with exception of birds become extinct?
by the end of the Cretaceous
what may have the extinction of dinosaurs been caused by?
an asteroid
what does the polygenetic position of turtles remain
uncertain
what are the boxlike shells of turtles made of?
upper and lower shields that are fused to the vertebrae, clavicles and ribs
what have some turtles adapated to?
deserts and others live entirely in pods and rivers
where do the largest turtles live?
in the sea
what are many species of sea turtles endangered by?
accidental capture in fishing nets or development of beaches where they lay eggs
what is one surviving lineage of lepidosaurs represented by?
two species of lizard-like reptiles, tuataras
what are living tuataras restricted to?
small islands off the coast of New Zealand
what are tuataras threatened by?
introduced rats which consume their eggs
besides tuataras what are other major living lineage of lepidosaurs? (3) (SLS)
1) squamates
2) lizards
3) snakes
what are the most numerous and diverse reptiles, apart from birds?
squamates
what are snakes?
leggless lepidosaurs that evolved from lizards
what type of animals are snakes?
carnivorous and have adaptions to aid in capture and consumption of prey
what does the adaption of snakes include? (4) (CHVL)
1) chemical sensors
2) heat-detecting organs
3) venom
4) loosely articulated jawbones and elastic skin
what do crocodilians (crocodiles and allligators) belong to?
an archosaur lineage that dates back to the late triassic
what are living crocodilians restricted to?
warm regions
what are birds?
archosaurs but almost every feature of their reptilian anatomy has undergone modification in their adaption of flight (not all birds fly)
what do many characters of birds have?
adaptions that faciliate flight
what is a major adaption of birds?
wings with keratin feathers
what do other adaptions of birds include? (4) (LFSL)
1) lack of urinary bladder
2) females with only one ovary
3) small gonads
4) loss of teeth
what does flight enhance for birds? (3) (HEM)
1) hunting and scavenging
2) escape from terrestrial predators
3) migration
what does flight require for birds? (3) (GAM)
1) great expenditure of energy
2) acute vision
3) muscle control
what did birds probably descend from?
small therapods (group of carnivorous dinosaurs)
what might have early feathers evolved for in birds? (3) (ICC)
1) insulation
2) camaflogue
3) courtship display
by 160 million years ago, what had feathered therapods evolved into?
birds
what remains as the oldest known bird?
archaeopteryx
what clade do living birds belong to?
neomithes
several speices of birds that are flightless (3) (eakRPC)
1) retites, order struthioniformes
2) penguins, order sphenisciformes
3) certain species of rails, ducks and pigeons
what did the demand of flight render the gernal body form for birds?
many flying birds similar to one another
characters that bird species can be distinguished by? (6)(PCFBBF)
1) profile
2) color
3) flying style
4) behavior
5) beak shape
6) foot structure
what are mammals?
amniotes that have hair and produce milk
what class are mammals and what are they represented by?
mammalia, represented by more than 5300 species
derived characters of mammals (MHHLD) (5)
1) mammary glands which produce milk
2) hair
3) a high metabolic rate, due to endothermy
4) a larger brain than other vertebrates of equivalent size
5) differentiated teeth
what type of animals are mammals?
synapsids
in the evolution of mammals from early syapsids what were two bones that formerly made up the jaw joint incorporated into?
the mamalian middle ear
by the early creataceous what did the three living lineages of mammals include? (MME)
1) monotremes (egg laying)
2) marsupial
3) eutherians
what did mammals NOT undergo?
significant adaptive radiaion until after the cretaceous
small group of egg-laying mammals consisting of echidnas and the patypus
monotremes
what do marsupials include? (3) (OKK)
1) opossums
2) kangaroos
3) koalas
what does the embryo of marsupials develop within?
a placenta in the mother’s uterus
when is a marsupial born?
very early in its development
when does marsupials complete embroynic development?
while nursing in a maternal pouch called a marsupium
in some species of marsupials such as the bandicoot what happens?
the marsupian opens to the rear of the mother’s body
in Australia what did convergent evolution result in?
a diversity of marsupials that resemble eutherians in other parts of the world
compared to marsupials what do eutherians have?
a more complex placenta
where do young eutherians complete their embryonic development within?
a uterus, joined to the mother by the placenta
what gives conflicting dates on the diversification of eutherians?
molecular and morphilogical data
what does the mammalian order Primates include? (4) (LTMA)
1) lemurs
2) tarsiers
3) monkeys
4) apes
what are humans members of?
the ape group
what are the 3 main groups of living primates? (3) (LTA)
1) lemurs, lorises and bush babies
2) tarsiers
3) anthropoids (monkeys and apes)
what derived characteristic do most primates have?
hands and feet adapted for grasping and flat nails
what does the oldest anthropoid fossils about 45 million years old indicate?
that tarsiers are more closely related to anthropoids than to lemurs
where did the first monkeys evolve?
in the Old World (Africa and Asia)
when did monkey first appear in the New World (South America)?
roughly 25 million years ago
what did the New and Old world undergo during their many millions of years of separation?
separate adaptive radiations
what do the other group of anthropoids consist of?
primates informally called apes
what does the ape group include? (6) (GOGCBH)
1) gibbons
2) orangutans
3) gorillas
4) chimpanzees
5) bonobos
6) humans
where did apes diverge from 25-30 million years ago?
old world monkeys
what are humans?
mammals that have a large brain and bipedal locomotion
how old is the species Homo Sapiens?
200,000 years old
characteristics of humans that distinguish them from other apes (4) (ULRS)
1) upright posture and bipedal locomotion
2) larger brains
3) reduced jawbone and jaw muscles
4) shorter digestive tract
what is the human’s larger brain capable of? (4) (LSAM)
1) language
2) symbolic thought
3) artistic expression
4) the manufacture and use of complex tools
how identical are the human and chimpanzee genomes?
99%
what can have a large effect on humans?
change in regulatory genes
the study of human origins
paleoanthropology
what are hominins (formerly called hominids) more closely related to?
humans more than chimpanzees
what did paleoanthropologists discover about humans?
fossils of about 20 species of extinct hominins
what does the oldest fossil evidence of hominins date back to?
6.5 million years ago
what did early hominins show evidence of?
small brains and increasing bipedalism
what is the correction for the misconception that early hominins were chimpanzees?
hominins and chimpanzees shared a common ancestor
what is the correction for the misconception that human evolution is like a ladder leading directly to homo sapiens?
Hominin evolution included many branches or coexisting species, though only humans survive today
a paraphyletic assemblage of hominins living between 4 and 2 million years ago
australopiths
what species of australophiths walked fully erect?
Australopithecus afarensis
what did “robust” australopiths have?
sturdy skulls and powerful jaws
what were “gracile” australopiths?
more slender and had lighter jaws
when did hominins being to walk long distances on two legs?
about 1.9 million years ago
what was bipedal walking?
energy efficient in the arid environments inhabited by hominins at the time
what showed the oldest evidence of tool use 2.5 million years ago?
cut marks on animal bones
what did fossil evidence indicate about tool use?
that it may have originated prior to the evolution of large brains
what are the earliest fossils place in our genus Homo ranging in age from 2.4 to 1.6 million years ago?
Homo habalis
what was found with homo habalis and which gave them this nickname?
stone tools, “handy man”
what was the first fully bipedal, large-brained hominid
Homo ergaster
when did Homo ergaster exist?
between 1.9 million and 1.5 million years ago
what did homo ergaster show a significant decrease in?
sexual dimorphism (a size difference between sexes) compared with its ancestors
what was homo ergaster fossils previously assigned to but most paleoanthropologists now recognize them as separate species?
homo erectus
where did homo erectus originate 1.8 million years ago?
Africa
what was the first hominin to leave Africa?
Homo Erectus
where did neanderthals live and when?
in Europe and near east, from 350,000-28,000 years ago
characteristics of neanderthals (3) (TBM)
1) thick-boned with a larger brain
2) buried their dead
3) made hunting tools
what did recent genetic analysis indicate that occured between neandherthals and homo sapiens?
gene flow
when did homo sapiens appear and where?
in Africa by 195,000 year ago
what are all living humans descended from?
these African ancestors
where do the oldest fossils of homo sapiens originate and date back to?
the Middle East, 115,000 years ago
when and where did humans first arrive?
in the New World sometimes before 15,000 years ago
what new fossil was found in 2004 of an 18,000 year old fossil in Indonesia ?
Homo floresiensis
what were homo sapiens first groups to show evidence of?
symbolic and sophisticated thought
what was found in 2002 in South Africa?
a 77,000 year old artistic carving
