Bio final chapters 30,31,32,33,34 Flashcards
lissamphibians
thin moist skin
monophyletic group
skin is permeable for water and gases
gas exchange can happen in lungs or through skin
rely on water or moist envirnoments
spawn in water by laying eggs
external and internal fertilization
eggs simple lack protective shell or extraembryonic memebrane
gymnophiona
caecillians lissaamphibians
paired protrusible tentacles- moved by eye muscles
eyes reduced
venom glands along jaw
urodela
lissamphibians- salamanders
patterns in formation of bones
anura
lissamphibians- frogs
postnatal development consists of full metamorphosis tadpole to adult
no post anal tail hindlegs elongated for swimming
Amniotes
monophyletic group that includes birds reptiles and mammals
amniotes shared derived features
1.embryo develops within amniotic egg
2. internal fertilization by intromittent organs
3.direct development
embryo develops in amniotic egg
amnion- surrounds embryo
allantois-stores metabolic waste
chorion- surrounds and cushions embryo
shell- protects embryo
allantois and chorion-gas exchange
yolk sac and albumen- nutrients to embryo
shell chorion and amnion-protect embryo
basal amniotes-leathery shell
evolutionary modification- calcium hardened
internal fertilization by intromittant organs
external genitalia specialized for transported sperm, internal fertilization is necessary because amniotic eggs are developed within body
direct development
larval stage and metamorphesis are absent
adaption in amniotes for terrestrial life
keratinised skin that is relatively impermeable to water
breathing is achieved by costal ventilation-movement of the ribcage by muscles to pump air in and out of lungs
gas exchange- exchange between small air tubes and capillaries in lungs
Amniote skull types
temporal fenestra- large opening on temporal region behind eye on skulls in amniotes
anapsids- absence of temporal fenestra (turtles)
synapsids- one pair or lower temporal fenestra
diapsids- two pairs of temporal fenestra behind eye socket
taxa with each skull
s- mammals and close relatives only in lineages leading to mammals
a- basal amniotes close to last common ancestor or reptiles and birds, turtles plesiomorphic
d-lizards snakes crocodiles, extant birds modified several times among reptiles
Charateriistics of non avian diapsids
1.thick keratinised scales over body
2.reproductive adaptation- oviparous laying amniotic eggs some are viviparous giving live birth, parental care to egg or hatchlings is not common
3. circulation- muscular heart with 3 chambers croc-4
4.thermoregulation- ectothermic rely on external heat sources to regulate body temp
Phylogeny of diapsida
2 lineages
lepidosaur- tuataras, lizards, snakes and fossil mosasaurs
archosaur- crocodiles, pterasaurs, and dinos
pterasaur were first tetrapod to fly
lepidosaur
monphyletic group of tuataras and squamates (lizards and snakes)
1.Overlapping keratinised scales periodically shed skin
2. presence of tail anatomy
lepidosaur- squamates
snakes and lizards
quadrupedal lizard like body
or amphisbaenians with reduced limbs or without limbs
limbless snakes
loss or reduction of limbs happened independently
1. flexible loosley jointed skull
2.deterministic growth- growth completely terminates
3. hemipenis as intromittent organ
notable squamates
chameleons, gila monsters-omnivores, snakes
archasauria- birds
evolved from bipedal theropod dinos
1. feathers- homologous to scales in other diapsids
2.reduced number of digits
3. absence of teeth instead have keratinised beaks
4. hollow bones
5. 4 chamber heart
6. fixed lung with one way airflow
7. endothermy only birds and mammals are endothermic use metabolic energy to maintain body temp
8. wide range of parental skills- precocial birds-born feed themselves or altricial birds- rely on parental care
archasauria- crocodiles
semiaquatic
inhabit freshwater
carnivorous predators dont chew
1.4 chamber heart
ectothermic
2.presence of a single medial penis as intromittant organ
3. protective maternal behaviour
diapsida- archasauria
monophyletic group
birds, crocs
ankle anatomy is used to classify two lineages of leading to crocs and birds
characteristics of mammals
1.presence of hair- thin shaft of keratin
2. endothermy- use metabolic energy to maintain body temp
(endothermy and 4 chamber heart suggest high metabolic rates in extant mammals)
3.mammary glands to provide younglings with milk maybe evolved from sweat glands
4. Presence of three middle ear bones- for the detection of higher frequency sounds
5. presence of dentary squamosal jaw joint- enlarged dentary bone
6.jaw with heterodonty teeth multiple tooth types diphyodonty which means they have two sets of teeth in life
7.expandable lungs with thwo way air flow
8. single intermittant organ for fertilizization
precocial- feed themselves atricial- rely on parental care
what are mammals evolved from
synapsids
clade includes mammal like reptiles and therapsids which are mammals
3 clades
monotremata
marsupial
placentalia
monotremata
echidnas and platypus
plesiomorphic traits lost in other mammals
-soft leathery non calcified eggs
-cloaca single opening for genital
-lactation without nipple milk is secreted onto fur
leathery beak instead of teeth NOT homologous with other beaks
Shared derived features of theria
(marsupials and eutherians)
1.Therians are viviparous give birth to developed embryo
2.placenta that proved nourishment consisting of extraembryonic membrane and lining of uterus
-gas exchange, nutrients and waste management
3.nipples to nurse offspring- outlets from mammary glands
