Diversity, classification and evolution Flashcards
how many extant species:
~65 000
vertebrates: list 2 major groups
- non-amniotes
- amniotes
non-amniotes: list
- agnathans
- chondrichthyes
- osteichthyes
- amphibians
aminotes: list
- reptiles
- birds
- mammals
amnion: features
- 2 major groups based on whether amnion exists
- one of 3 membranes within egg, immediately surrounding embryo
- (other 2 are chorion, allantois)
- division roughly aligns w terrestrial/ aquatic life
- amoniotic fluid so embryo bathed in liquid similar to fish and amphibian embryos
non-amniotes: features
- protected by 2 membranes
- fishes, amphibians
- roughly corresponds to aquatic verts
non-amniotes list phylogenetic classification: verts (least - most specific) (4)
- craniata
- vertebrata
- gnathstomata
- osteichthyes
non-amniotes phylogenetic classification: craniata eg.
hagfish (myxiniformes)
non-amniotes phylogenetic classification: verterbata eg.
lamprey (ptermyzontiformes)
non-amniotes phylogenetic classification: gnathostomata eg.
sharks, rays (chondrichthyes)
non-amniotes phylogenetic classification: osteichthyes eg.
lobe-finned fish (sarcopterygii)
non-amniotes craniata: shared characteristics
- brain case
- gills
- distinct head
- differentiated digestive organs
- ventral pumping heart (under neural control)
- tripartate brain
- neural crest cells
- closed circulatory system
eg. hagfish
- eel-like
- known for copious amounts of mucus
- purely marin
- mouth surrounded by tentacles
- scavengers on dead creatures
- accessory hearts
- iso-osmotic
- single semi-circular canal (front/back)
- rudimentary vertebrate (not actual bones)
~70 species
non-amniotes vertebrata: shared characteristics
craniata +
- backbone of vertebrate
- radial fin mm. control movement of limbs/ fins
- 2+ vertical semicircular inner ear canals
eg. lamprey
- marine and freshwater (many move btw two as part of lifecycle)
- pest species (parasites) of other fishes
- sucking disk
- soft bodied
- scaleless
- single, central nostril
- amnocoetes larval form= only filter feeds
~38 species
non-amniotes gnathostomata: shared characteristics
- jawed vert
- teeth
- paired appendages (pectoral, pelvic fins)
- horizontal semicircular inner ear canal (total 3)
- paired nostrils
- 5 gill slits
- series gill arches
eg. chondrichthyes (sharks, rays etc.)
chondros= cartliage icthys= fish
- skates, chimearas
- cartilaginous skeleton
- solid brain case
- 5-7 pairs of gills (and assoc complex arterial sys)
- 2 chambered heart
- intestine w spiral valve
- claspers present in males
- no swim bladder
- teeth at jaw margin
- paired nares
~1200 species (pelagic great whites- deadly vs. majority benthic)
non-amniotes osteichthyes: 2 main classifications
- ray finned fish (actinopterygians)
- lobe finned fish (sarcopterygians)
non-amniotes osteichthyes: shared characteristics
- well ossified bony skeleton
- pair of lungs/ swim bladder (evolved from lungs- maybe 2º lost)
- bony fin rays
eg. actinopterygii (ray finned fish)
aktis= ray pteryx= wing/fin
- single gill opening covered by operculum
- paired fins supported by bony rays
- dorsal fin
- swim bladders mainly hydrostatic
- 2 chambered heart (atrium/ventricle not divided) + conus arteriosis
~32 000 species
most dom class of vert on planet
eg. sarcopterygii (lobe finned fish)
sarkos= flesh pteryx= wing/fin
- single gill opening covered by operculum
- paired fins (limbs) w sturdy internal skeleton and musculature
- single bone connects limbs to girdle (similar to tetrapods)
- diphycercal tail (vert column extends to tip)
- atrium and ventricle party or fully divided
- internal nares
- teeth covered w enamel
eg. name 2 fish classification
- Rhipidistia
- Actinistia
eg. rhipidistia
dipnoi and tetrapodomorpha
eg. lungfish (8 species)
eg. actinistia
ceolcanth (2 species)
eg. tetrapodamorpha:
- vert w 4 legs, tho maybe 2º lost
non-amniotes amphibia: shared characteristics
amphi= both bios= life
- eg. frogs, salamanders
- ectothermic tetrapods
- respiration by lungs/ gills/ skin
- eggs laid in water/ moist env
- dev through aquatic larval stage
- skin moist w mucous glands, no scales
- bones support fish jaw now ear bones
- eyelids
- 3 chambered heart (divided atria)
- urinary bladder (1º waste is urea)
amniotes classification: main classifications
- sauropsids
- synapsids (mammals)
amniotes reptilia shared characteristics:
repere= creep
- turtles, crocodiles, lizards, snakes
- ectothermic tetrapods
- respiration via lungs
- embryo dev into shelled egg (amnion present)
- no larval stage
- skin dry, lacking mucous glands
- epidermal scales
- 3 chambered heart (2 atria, ventricle partially divided)
- no 2º pallet (must hold breath while swallowing)
- kidneys present but not well developed (uric acid, urea principal waste, salt glands)
- inner, middle ear
~8100 species
amniotes aves shared characteristics:
ave= bird
- endothermic for forelimbs modified for flight
- body covered w feathers
- bipedal, scales on feet)
- flattened ribs, keeled sternum for flight mm attachment
- toothless, beaked jaws
- complex vert (v flexible neck)
- flow through lungs
- 4 chambered heart
- well dev kidneys (main excretion= uric acid)
~9700 species
amniotes mammalia shared characteristics:
mamma= breast
- endothermic vert
- high metabolism
- 4 chambered heart
- possess mammary glands (specialised sweat glands)
- body covered w hair
- brain large w neocortex
- 3 middle ear bones
- distinctive jaw + cranium
- erect limb posture
- tidal lungs w alveoli
- bondy 2º pallet (eat/ breathe simultaneously)
~4800 species
taxonomy: invented by
- linnaeus
- binomial sys,
- hierarchal ‘ranking’ sys
- higher taxa have ranks
- species back then places into same genus based on morphological characters
- no concept of evol/ genetics
taxonomy classes:
phylum - class - subclass - order - family - genus - species (broad - specific)
cladistic analysis: parsimonious tree
- requires fewest evolutionary events (appearance of shared derived characters)
phylogentic systematics: define clade
- group of organisms related through common descent
phylogentic systematics: define derived
- different from ancestral condition
phylogentic systematics: define members of clade have
- shared derived characters
phylogentic systematics: define apomorphy
- derived character
phylogentic systematics: define synapomorphy
- shared derived character
eg. shared derived character
- forelimbed structure on terrestrial vert, lobe-finned fish
define plesiomorphies:
- shared ancestral traits
eg. plesiomorphies:
vert have vertebral column
define symplesiomorphies:
- shared ancestral traits
- BUT doesn’t tell about how closely related species are
define: polarity
- direction of change
define: outgroup
- species that are more distantly related
define: monophyletic
- evol lineages must have single evolutionary origin
define: dichotomous branches
- come out from theoretical ancestor
define: crown group
extant species
define: stem group
extinct species
define: paraphyletic and eg.
- don’t contain all decendents from common ancestor because stem group taxa excl by definition
cladograms: features
- capture traits of animals that share common heritage
define: sister group
- monophyletic lineage closely related to lineage being discussed
homology vs analogy:
- some traits derived from common ancestry (homologous)
- eg. wings developed independently are analogous, evolved through convergent evol
parallel evolution: and eg.
- species recently diverged dev similar specialisations (eg. jerboa and kangaroo rat- long hind limbs for hopping)
reversal evolution: eg.
- vert started out in water being streamlined, important
- reptiles, birds, mammals returned to water and adopted stream-lined shape
- terrestrial w well dev limbs returned to aquatic env reverted to body form
- penguin, dolphin
define: homoplasy
- convergence, parallelism, reversal all forms of homoplasy
- homoplastic similarities not indicative of common ancestry
- convergent and parallel evolution falsely suggest common evolutionary og.
- reversal conceals common orgins
