Animals IV Flashcards
Deuterostome characters
- triploblastic
- coelomate
- radial cleavage
- anus first
- coelom from mesoderm pouches
- internal skeleton and segmentation (some)
Deuterostome phylogeny
-based on molecular data bc no unigue or derived diagnostic characters
Bilateria ancesteral condition
- blastopore = anus
- radial cleavage
- protostomes are derived
Deuterostomes ancestral condition
- bilateral symetry
- segmentation
- pharyngeal slits
- chordates still have these
- echinoderms are derived
Deuterostome gps
Ambulacrarians (echinoderms and hemichordates)
Chordates
Hemichordata
- used to be chordate subphylum
- bilateral symetry in larva and adults
- acorn worms and pterobranchs
- acorn worms = solitary marine worm-like anials that live in burrows –> deposit or suspension feeders
-most similar to CA of chordates and rest of deuts
Echinoderm clades
Asteroidea = sea stars Ophiuroidea = brittle stars Echinodea = sea urchins Crinoidea = sea lilies Holothuroidea = sea cucumbers
Echinoderm characters
- all marine –> no osmoregulation
- sessile or slow moving adults
- no pharyngeal slits
- radially symetrical adults (bilaterally symetrical larvae)
- most gonochoric, some hermaphroditic
- some regenerate lost parts and do asexual reproduction
- dkin covers ENDOSKELETON of calcareous plates
- water vascular system and tube feet (ancient)
chordata groups
Urochordata - marine
Cephalochordata - marine
Vertebrates - marine and terrestrial
chordata history
-from cambrian
Pikaia
- cambrian cephalochordate originally described as polychaete worm
- segmented with a notochord
chordate characters
notochord muscular, post anal tail pharyngeal slits dorsal nerve cord endostyle
Urochordata
- tunicates
- look like fish as larvae
- sac-like sessile adults
- filter feeders
Cephalochordates
- lancelets
- burried fish-like things with tentacles that stick out
Vertebrate characters
- anterior skull with big brain
- rigid endoskeleton (bony or cartilaginous) supported on vertebral colimn (except hagfishes
- well developed closed circulatory system with heart
- coelom with suspended organs
endoskeleton
allows continuous growth and large size
vertebrate fossil
-rare
-oldest one is Haikouichthys
-one of several Cambrian jawless vertebrates from China
530 mya
-dunno if bony or cartilaginous
-distinct head, tail, and gills
might be an older one from 560 mya
conodonts
- tooth like structures in cambrian strata up to jurassic
- distinctive index fossils
- now known to be parts of jawless vertebrates
- made of jydroxylapatite –> same as vertebral bones
Fish HOX genes
- lots of duplication
- probably led to radiation
ostracoderms
- jawless fish with boy armor 440 mya
- first fossil fish to be described in 1830s
Clystomes
- skeleton
- molecular data
- environment
- feeding
- development
- hagfish
- cartilaginous endoskeleton
- no complete vertebral column
- persistant notochord
- molecular sisters to lampreys
- incomplete skull with brain (no cerebrum or cerebellum)
- tooth-lie keratin structures
- all marine
- scavengers, predators, and suspension feeders
- direct dvlpmnt (no larva)
- makes defensive slime
cyclostomes
- lampreys
- adult is sometimes a fish ectoparasite and larvae are filter feeders
- complete metamorphasis to adult
- complete braincase
- rudimentary vertebral column
- cartilaginous endoskeleton with horny keratinous teeth
- molecular sisters of hagfish and together are sis to other vertebrates
Jawed fish
- chondrichthyans, ray finned, lobe finned
- have jaws developeded from first gill arch
- prob adaptice originally in pumping of water across gills
- from ordovician and radiated in devonian
Placoderms
ancient jawed fish
- teeth are outgrowths of jaw
- fish and reptilian teeth all same type (homodont) and replacable
- mammalian teeth heterodont and fixed number
Chondrichthyans
- sharks, rays, chimaeras
- split with bony fish 420 mya
- mostly marine
- no lungs or swim bladders
- internal fertilization
- live young; no parental care
- skin covered by placoid scales (homologous to vertebrate teeth) –> cant grow in size but increase in number
shark teeth
- also placoid scales
- continually lost and replaced
- outward movement of old ones
- not attached to endoskeleton
- common as fossils
miocene sharks
- great diversity of shark species lived in warm offshore waters of mid atlantic
- shark teeth common on beaches
- mos were similar to present sharks
- Carcharondon megalodon is famous
rays
- close relatives of sharks
- largest number of chondrich species
- dorsiventrally flattened bodies , enlarged pectoral fins fused to head and ventral gill slits
- mostly marine and feed on invertebrates close to the sea floor in coastal areas
- manta rays eat plakton
osteichthyan characters
-marine and freshwater
CaPO4 in cartilage matrix to form bony skeleton
-fins with rods of cartilage for ray finned
-hearts with two chambers
-most have swim bladders derived from lungs (lungs in basal fish)
Actinopterigians
ray finned fish
- most dominant class of vertebrate
- bony endoskeleton and fins with spines
- teleost are most diverse
sarcopterygians
-lobe finned
-coelocanths and lungfish
-latimeria spp =living fossil coelocanth
-fleshy lobed fins
-2 coelocanth spp and Rhipidistia with 6 spp lungfish and tetrapods
-most went extinct at end of permian
lungfish more closely related to tetrapods
lungfish
- 6 spp left
- retain many charateristics of ancient bony fish and sarcopterygian
- homologous lungs to those of tetrapods –> evolved from pharyngeal air sacs in CA of jawed bony fish –> retained in lobe finned –> swim bladders in ray finned
land flora and fauna dates
oldest land plant 470 mya ordic oldest arthropod 450 mya ordic oldest land animals 428 mya (silurian) Tiktaalik = early semi tetrapod 375 dev seed plants 360 mya amniotes 340 mya
problems with moving to land
- mass and structural support
- locomotion
- air breathing
- feeding (can’t filter)
- sensory
- water loss
- reproduction (first seed plants and amphibians need water to reproduce)
Tiktaalik
- discovered 2004 in canada
- from devonian 375 mya
- sarcopterygian fish
- important transition animal
- limbs intermediate between aquatic fish and terrestrial tetrapods
Amphibian characters
-skeleton mostly bony 4 limbs 3 chambered heart (2 atria; 1 ventricle) gas exchange thru skin carnivors as adults both lungs and gills during life
Eryops vs modern amphibians
- temnospondyl amphibian from permian 295 mya
- one of biggest land animals of its time
modern amphibians can be big but most are really small
Lissamphibia clades
Anura = frogs and toads (most)
Caudata or Urodela = salamander (mid)
Gymnophiona or apoda = caecilians (least)
Amphibians water or land?
- not fully adapted to either
- usually aquatic as larvae and terrestrial as adults
- gills turn to (inefficient) lungs
- ectothermic (don’t reg body tmep)
- some retain larval characteristics into adulthood: e.g. axolotyl remains aquatic with gills
anura
frogs and toads
- carnivorous and tailless as adults
- herbivorous tailed larvae
- glandular skin is defensive
- warty frogs called toads
- larvae = tadpoles with internal gills
- complex vocalization and breeding behaviors
caudata
- salamanders
- 550 spp
- from jurassic
- moist skins; skin glands
- tailed as larvae and adults
- capable of regenerating lost limbs
Apoda
- Caecilians
- completely legless
- nearly blind
- mostly tropical; live in soils and are seldom seen
- look like earthworms
- earliest from Jurassic–> fully developed legs and eyes
- internal fertilization and development of young inside female
- remarkable maternal care –> babies eat mom’s skin
