Comparative Anatomy
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- embryonic development
- zygote goes from one cell to an org w/ organs
- What is closest related phylum?
- Hemichordata
- 4 diff b/w us and jellyfish (what we share with starfish)
- 1. Skel sys derv from mesoderm in deuterostomes, ecto in protostomes 2. spiral cleavage in proto, radial in detero 3. body cavity forms enderocoely in deutero, schizocoely in proto 4. blastopore becomes mouth in proto, anus in deutero
- 3 subphyla of Chordata
- Urochordata, Cephalachordata, Vertebrata
- Chordates + Hemichordates
- "protochordates"
- first fossil
- Pikaia
- Notochord
- Slender, flexible rod, lends support Mesoderm Prominent in lamprey/shark some becomes nuleus pulposes
- Dorsal, hollow nerve cord
- ventral in protostomes ectoderm
- Pharyngeal slit
- used for feeding, later respiration
- Endostyle/ thyroid gland
- ventral iodine metabolizing organ
- Which of 5 chordate char do hemichordates have?
- Pharyngeal slit
- Enteropneosta
- Hemichordata Proboscis, collar, trunk excrete t/ skin blood lacks pigment nervous system, no brain gonads in trunk- dioecious Tornaria larva
- Pterobranch
- Hemichordata colonial proboscis, collar, trunk digestive system is U-shaped
- Cephalachordates
- lancelets/amphioxus chordates suspension feeders lack brain, heart
- Urochordates
- Ascidacea- tadpole larva (all 5 char), adult (only 2 char-> endostyle and pharynegeal slit) Larvacea- all 5 char in adult Thaliciacea- free floating adult Monoecious
- Synapomorphy
- shared derived char
- Plesiomorphy
- ancestral char
- synapomorphies of vertebrata
- brain vertebral column head w/ paired multicellular special sense organs paired appendages kidneys neural crest cells bone division of NS into somatic vs autonomic NOTE: these things aren't necesarily unique to animal kingdom, just chordata
- grade vs. clade
- grade- does not imply evolution, similarities in morph clade- monophyletic (shares a common ancester)
- homocercal tail vs heterocercal
- homo- symmetric, teleost fish, swim bladder keeps a float hetero- asymmetrical, cartilaginous fish (sharks), keep from sinking w/ help of large oily liver
- modifications to incr SA in larger
- metabolism- intestines have folds, microvilli-> villi-> plicae cirrularis respiration- mammal lungs- avioli circulatory- capillary beds
- Allometry
- porportion changes as size changes (alien baby)
- Isometry
- proportion stays the same even if size changes
- life history
- ovum + sperm -> fertilization -> zygote -> embryoni development -> hatching/birth -> larval/ juvenile -> sexual maturity -> adult -> senescence
- senescence
- loss of reproductive ability and physical vigor only a few reach this - us, whales, turtles
- cleavage
- rapid cell division with little growth leads to blastula
- extra-embryonic membranes
- yolk sac amniotes also have amnion, chorion, allantois
- macrolecithal
- lots of yolk
- mesolecithal
- middle amount of yolk
- microlecithal
- very little yolk
- isolecithal
- cells in embryo divide evenly (assoc. w/ microlecithal)
- telolecithal
- uneven development of embryo, (assoc. w/ macrolecithal), gives polarity
- ovum membranes
- 1. plasma membrane 2. primary egg envelope- called zona pellucida in mammals, protein layer external to cell memb 3. secondary egg envelope- layer of follicular cells, called corona radiata in humans (4)- tertiary egg envelope- produced by oviduct in some, becomes egg shell in birds+ some mammals, leathery case in sharks, albunum (jelly) in amphibians, not produced if viviparous
- gestation
- period of time where embryo resides w/in female's body (viviparity)
- oviposition
- egg-laying
- parturition
- giving birth to live young
- lecithothophy
- no contribution of female to energy needs of embryo, only yolk
- matrotrophy
- mother provides energy to embryo - placenta - blood -> some sharks feed directly off blood in uterus - unovulated eggs (sharks) -also see cannibalism
- morula
- dense mass of cells produced early during cleavage
- blastula
- produced by cleavage, undifferentiated/ totipotent (time when identical twins occur), hollow sphere of cells, cvity called blastocoel, cells called blastomere
- holoblastic cleavage
- produces sphere, even development, cells all the same size, assoc with microlecithal eggs, isolecithal eggs
- meroblastic cleavage
- uneven development of blastula, disk instead of sphere, macrolecithal, telolecithal
- gastulation
- where cell differentiation occurs, results in tissues embryo forms tube called archenteron (primative gut) -pattern is called invagination in mammals
- neurolation
- ectoderm (dorsal) forms neural plate beneath neural plate mesoderm becomes notochord neural plate becomes a fold, leads to nerve cord mesoderm differentiates
- ectoderm -> epiderm -> ?
- epidermis, mouth, cloace
- ectoderm -> neural plate -> ?
- nervous system
- ectoderm -> neural crest ->
- various
- mesomere -> epimere -> ?
- sclerotome (axial skeleton), dermotome (dermis), myotome (muscle)
- mesomere -> mesomere -> ?
- kidney and urogenital ducts
- mesoderm -> hypomere -> ?
- limbs, gonads, heart, mesentaries
- endoderm -> foregut -> ?
- pharynx, esophogus, trachea
- endoderm -> midgut -> ?
- stomach, liver, pancreas
- endoderm -> hindgut -> ?
- urinary bladder
- histogenesis
- differentiation of embryonic tissues
- epithelium
- cellular, all 3 emb tissues, free surface + basal layer, also makes glands
- exocrine
- glandular secretion released into duct which carries out of organ
- endocrine
- ductless gland, secretion released into blood stream, example is thyroid
- connective tissue
- specialized cells + a matrix, bone, blood, cartilage, adipose, dense formed by mesoderm
- muscle
- skeletal - mesoderm, generic movement cardiac - mesodern, involuntary, myogenic heart (heartbeat orig. w/in heart) smooth - involuntary muscles, peristalsis (invol. gut movement)
- nervous
- ectoderm only, irratability (ability to detect stimuli) and conductivity (can relay info from one tissue to another by action potentials)
- yolk sac
- endoderm, amniotes and anamniotes have
- amnion
- ectoderm, surrounds only embryo
- chorion
- ectoderm, outermost etraembryonic layer
- allantois
- endoderm, wastesite, facilitates exchange b/w embryo and blood supply in placenta
- coelum
- forms in hypomere divides during development in to pericardial cavity and pleuroperitoneal cavity, divided by transverse septum in mammals additional division made in pleuroperitoneal cavity into plerral and peritoneal cavities
- kidneys
- mesomere, develop outside body cavity in retroperitoneal
- paedomorphy
- juvenile char retained in the adult
- heterochrony
- shift in onset or timing of features of an organism in a descendant as compared to ancestor
- peramorphy
- adult char of ancestors become exagg. in desc.
- hypermorphasis
- features grow larger for a longer amount of time (results in exagg. adult traits)
- acceleration
- features develop faster in descendent (results in exagg. adult traits)
- predisplacement
- features develop earlier in development comp to ancestor
- progenesis
- somatic development ceases early, sexual maturity comes early - webbed feet in salamanders?
- neoteny
- feeatures grow at a slow rate, sexual maturity overcomes somatic development -mudpuppies?
- postdisplacement
- feature is offset so late in development that it never appears
- Haekel's Biogenic Law
- "ontogeny recapitulates phylogeny"- thought we could see ancestor in embryonic development
- epidermis
- stratified squamous epithelium, gives rise to hair, feathers, baleen, nails, claws, beak, some scale types, outer layer of horn
- dermis
- dense, irregular connective tissue, inc nervous tissue, adipose, blood vessels may be glands, dermal bones
- hypodermis
- subutaneous layer, superficial fascia not derived from integument, cushions skin
- melanocytes
- produce pigment, from neural crest cells
- scales
- folds in integument, fish have dermal scales, reptiles have epidermal
- teeth
- interaction if epidermal and dermal enamel -> ameblasts -> epidermal cells dentin -> odentoblasts -> dermal cells
- functions of integument
- protection, barrier to microorganisms, mechanical abrasion, rich with blood, thermal regulation many verts breathe t/ skin color, camouflage, species/sexual recognition osmoregulation, controls water content of the body
- layers of epidermis
- periderm (outer) stratum basale (where cell division occurs) SB separated from dermis by basement membrane basement mem- basal lamina (collagen) and reticular lamina (reticular fibers), secretes protien
- Horns
- bony core covered in keratinized sheath Grow for life
- Antlers
- bony core covered in vascularized skin (velvet) shed annually
- Charles Darwin
- Natural selection- 1. high repro rate, 2. competition, 3. survival of the few, which survive is det by natural selection
- Carlus Linnaeus
- species immutable, devised system for naming plants/animals
- Jean-Baptiste de Lamarck
- species evolve toward the perfect (us), inheritance of acquired characteristics
- Alfred Wallace
- Also came up with natural selection, published first paper on topic with Darwin
- Thomas Huxley
- "Darwin's Bulldog"
- Richard Owen
- believed species immutable, archetypes
- Georges Cuvier
- parts perform a specific function, if they changed nothing would work
- homology
- parts share a common ancestor (ex bones in mammals)
- analogy
- parts have a similar function (bat wing, bird wing)
- homoplasy
- features look alike (stick, stickbug)
- preadaption
- structure or behavior existed before biological role (ex feathers existed for warmth before they were used for flight)
- Age of earth
- 4.6 by
- Paleozoic
- Age of Fishes
- Mesozoic
- Age of Reptiles
- Cenozoic
- Age of Mammals
- Agnathan
- jawless fishes- cyclostomes -> hagfishes and lampreys
- Myxinoidea
- hagfish
- Petromyzontida
- Lampreys
- Gnathostomes
- jawed fished (and tetrapods)
- Chondrichthyes
- cartilagenous fish sharks, rays, and ratfish
- Osteichthyes
- bony fish
- Actinopterygii
- Ray-finned fishes
- Sarcopterygii
- fleshy-finned fishes gave rise to tetrapods lungfish, coelacanths
- Lissamphibia
- amphibians
- Urodela
- Salamanders
- Anura
- Frogs and toads
- Gymnophiona
- Caecilians
- anapsid
- 1 temporal fenestra mammals
- diapsid
- 2 temporal fenestrae reptiles, birds, crocs