40-1 copyright 2010 mcgraw-hill australia pty ltd powerpoint slides to accompany biology: an...
TRANSCRIPT
40-1Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Chapter 40: Echinoderms and chordates
40-2Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Deuterostomes• During embryonic development, the blastopore
becomes the anus• Phylum Echinodermata
– sea stars, sea cucumbers, sea urchins
• Phylum Chordata– acorn worms, sea squirts, lancelets, vertebrates
40-3Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 40.1: Deuterostome phylogeny
40-4Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Echinoderms• Sea stars, sea cucumbers, sea urchins, sea lilies,
brittle stars• Pentameric symmetry in adults• Characteristics
– calcareous endoskeleton– bilaterally symmetrical larvae– water vascular system
40-5Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Classification• Class Crinoidea (sea lilies, feather stars)
• Class Asteroidea (sea stars)
• Class Concentricycloidea (sea daisies)
• Class Ophiuroidea (brittle stars)
• Class Echinoidea (sea urchins, heart urchins, sand dollars)
• Class Holothuroidea (sea cucumbers)
40-6Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Echinoderm anatomy• Endoskeleton
– calcite (CaCO3) spicules or ossicles embedded in integument
• Larva– free-swimming, bilaterally symmetrical– pentameric symmetry develops at metamorphosis
• Water vascular system– coelomic canals– gas exchange and locomotion
40-7Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
The water vascular system• Water enters through sieve-like madreporite• Stone canal → ring canal → radial canals• Stone canal
– calcified tube, connects madreporite to ring canal
• Ring canal– runs around base of arms
• Radial canals– run along arms; tube feet and ampullae for locomotion
40-8Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 40.3: Structure of a sea star
40-9Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Chordates• Acorn worms, sea squirts, lancelets, vertebrates• Bilateral symmetry• Characteristics
– notochord – pharyngeal slits – dorsal hollow nerve cord
• Oldest fossils from Cambrian (530 million years ago)
40-10Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Classification• Subphylum Hemichordata (acorn worms,
pterobranchs)
• Subphylum Urochordata (sea squirts, tunicates)
• Subphylum Cephalochordata (lancelets)
• Subphylum Craniata (fish, amphibians, reptiles, birds, mammals)
40-11Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Chordate anatomy• Characteristics of chordates are present at some
stage of the life cycle• Notochord
– dorsal rod between nerve cord and gut, attachment point for blocks of muscles (myotomes)
• Pharyngeal slits– paired openings in pharynx, used for filter feeding in
some chordates
• Dorsal nerve cord– hollow nerve cord above notochord, expanded anteriorly
to form brain in some chordates
Fig. 40.9: Chordate features
40-12Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
40-13Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Subphylum Hemichordata• Acorn worms, pterobranchs• Characteristics
– tripartite body: proboscis, collar, trunk– pharyngeal slits filter food particles from water– mouth in groove between proboscis and collar– dorsal nerve cord in collar
• Marine, solitary (acorn worms) or colonial (pterobranchs)
Fig. 40.8: Acorn worm
40-14Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
40-15Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Subphylum Urochordata• Sea squirts, tunicates, salps• Characteristics
– notochord and dorsal nerve cord in pelagic forms (larvae and adults)
– incurrent and excurrent siphon for water intake and expulsion
– pharyngeal slits filter food particles from water– adult body encased in tunic composed of tunicin (form of
cellulose)
• Marine, solitary or colonial, sessile or pelagic
Fig. 40.10a, b: Tunicates
40-16Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
40-17Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Subphylum Cephalochordata• Lancelets• Characteristics
– notochord extends for full length of body– muscle blocks (myotomes) along body– pharyngeal slits filter food particles from water– oral hood with buccal cirri around mouth– dorsal and tail fins, paired metapleural folds
• Marine, solitary, benthic
40-18Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Subphylum Craniata• Jawless fish and vertebrates
– oldest fossil craniates are lower Cambrian (530 million years ago)
• Characteristics– head with cranium (skull) of cartilage or bone– brain with cranial nerves
• Marine, freshwater or terrestrial, solitary, mobile
40-19Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Agnatha• Lampreys and hagfish• Characteristics
– cartilaginous skeleton– notochord persists in adults– lack jaws
• Extinct jawless fish were bottom-dwelling filter or detritus feeders
• Modern jawless fish are blood-feeding ectoparasites or scavengers
40-20Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Gnathostomata• Vertebrates (fish, amphibians, birds, reptiles and
mammals)• Characteristics
– vertebrae replace notochord in adult– projections from vertebrae protect nerve cord and aorta– neural crest cells give rise to many structures in the head
and other parts of the body – dentine and enamel often form teeth or denticles
• Evolution of jaws from gill-arches allowed vertebrates to exploit a range of diets
40-21Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 40.13: Evolution of jaws
40-22Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Cartilaginous fishes: Chondrichthyes• Sharks, rays, skates, chimaeras• Characteristics
– skeleton of cartilage (frequently calcified)– fins with broad bases– no swim bladder– denticles in skin and along jaws
• Marine or freshwater (few species), benthic or pelagic
40-23Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Ray-finned fishes: Actinopterygii• Sturgeons, paddlefish, barramundi, eels,
seahorses, butterflyfish etc.• Characteristics
– skeleton of bone– fins with narrow bases, supported by bony rays – swim bladder present– jaw formed of teeth-bearing dermal bone
• Marine or freshwater, benthic or pelagic
Fig. 40.16a: Structure of a bony ray-finned fish
40-24Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
40-25Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Tetrapods and their relatives: Sarcopterygii• Lobe-finned fish: coelacanths and lungfish• Characteristics
– fins with broad, fleshy bases
• Sarcopterygians are the closest relatives of tetrapods (amphibians, sauropsids and mammals)– similarities in pelvic girdle, pectoral and pelvic
appendages, dermal bones and heart
• Marine or freshwater, benthic or pelagic
Fig. 40.17: Comparison between lobe-finned fish and tetrapod
40-26Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Question 1:
The hagfishes and the lampreys:a) are a sister group of the sharks because they have
cartilaginous skeletons
b) have a rasping tongue homologous with the radula found in most molluscs
c) have retained paired pectoral and pelvic fins
d) are closely related parasites that bore into the sides of their hosts and then quickly secrete large quantities of mucous
e) are probably not any more related to each other than they are to the other fishes but are grouped together because they both lack jaws
40-27Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
40-28Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Amphibia• Frogs, toads, newts, salamanders, caecilians• Characteristics
– skull with occipital condyles that articulate with vertebrae– single sacral vertebra– glandular skin without epidermal structures– eggs lack shells– lungs and skin used in gas exchange
• Freshwater and terrestrial
40-29Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Amniotes• Vertebrates (sauropsids, mammals)• Characteristics
– extra-embryonic amnion encloses embryo in fluid-filled sac
– embryonic allantois (outgrowth of hindgut) is used for excretion during development
– thick, waterproof skin with scales, hair or feathers– intervertebral disc– atlas and axis are first two cervical vertebrae
• Amniotes include Sauropsida (birds, ‘reptiles’) and Mammalia
40-30Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 40.20: Relationships of amniotes
40-31Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Sauropsida: Chelonia• Turtles, tortoises and terrapins• Characteristics
– body protected by dorsal and ventral shields (carapace and plastron respectively)
– shoulder (pectoral) girdle lies inside rib cage– anapsid skull (lacks openings to accommodate jaw
muscles)– jaws toothless
40-32Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Sauropsida: Lepidosauria• Snakes, lizards and tuatara• Characteristics
– teeth fused to edges of jaws– some species can shed tail at pre-formed fracture points
(autotomy)– snakes can disarticulate jaws to accommodate large prey
• Tuataras (Sphenodon) of New Zealand are ‘living fossils’– only surviving members of order Rhynchocephalia
40-33Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Sauropsida: Archosauria• Crocodiles, birds, dinosaurs• Characteristics
– diapsid skull with additional preorbital opening– moveable membrane over eye– muscular gizzard
• Most of the diagnostic characteristics of birds are adaptations to flight– birds are descendants of the dinosaur lineage
40-34Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Mammalia• Characteristics
– epidermal hair– milk production from mammary glands– left aortic arch carries systemic circulation
• Subclass Prototheria– Order Monotremata (egg-layers)
• Subclass Theria– Order Metatheria (marsupials)– Order Eutheria (placentals)
Fig. 40.29: Mammalian relationships
40-35Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
40-36Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Primates• Lemurs, tarsiers, monkeys, apes (including
humans)• Characteristics include
– prehensile digits and opposable thumb– bicuspid premolars, molars with three to five cusps– binocular vision, large brain
• Strepsirhini (lemurs, lorises, galagos, pottos)– rhinarium (nose pad) with slit-like nostrils
• Haplorhini (tarsiers, monkeys, apes)– nose with rounded nostrils
40-37Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 40.31: Phylogeny of primates
Question 2:
Extinctions of animal species:a) are sufficiently rare that most animal species that have
evolved are still present on the earth today
b) always occur every 5 million years
c) only occur as a result of major global events, such as asteroid impacts or climate changes
d) have occurred at a relatively constant ‘background’ rate during periods when global environmental conditions have been relatively stable
e) do not occur as a result of competition or predation
40-38Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
40-39Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
The first hominids• Characteristic bipedal gait of hominids frees hands
for grasping food, holding young, nest-building and tool-making
• Sahelanthropus tchadensis (7 to 6 million years ago)– Djurab Desert, Chad, Africa– ape-like brain case, short face and ‘human’ teeth
• Australopithecus (4.4 to 2.5 million years ago)– Ethiopia to South Africa – forward-jutting face, brow-ridge, ‘human’ hands and
molar teeth
40-40Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Paranthropus: robust forms• Tool-making hominids coexisted with Homo in
Africa• Paranthropus (2.8 to 1.6 million years ago)
– skulls with sagittal crests – powerful jaw with large premolars– vegetarian, used digging tools (probably for collecting
tubers and other plant material)
40-41Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Homo: increase in brain size• Oldest fossils of Homo are about 2.5 million
years old– H. rudolfensis and H. habilis coexisted with
Australopithecus in Africa
• Differences between Homo and Australopithecus– brain capacity of Homo larger than Australopithecus– reduction in jaw and tooth size in Homo– evidence of tool-making (H. habilis)
• More modern species with larger brain capacity– H. ergaster from Africa– H. erectus from Java (‘Java Man’) and China (‘Peking
Man’) made more sophisticated tools than H. habilis
40-42Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Out of Africa or a multiregional origin of Homo sapiens?• Out-of-Africa theory
– migration of anatomically modern humans from Africa, replacing all other populations of Homo
– mtDNA evidence suggests a common ancestor 170 000 years ago
• Multiregional theory– anatomically modern humans evolved semi-
independently from H. erectus–like ancestors simultaneously in different regions
Fig. 40.34: Suggested phylogeny of hominids
40-43Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Summary• Echinoderms, hemichordates and chordates are all
deuterostomes• Echinoderms are radially symmetrical as adults• Chordates are characterised by a dorsal notochord
and pharyngeal slits • All tetrapods other than amphibians are amniotes• Amniotes evolved into two major groups: the
sauropsids and the mammals
40-44Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University