March 2-7th Flashcards
water to land transition (13)
- lungs
- limbs with digits
- pulmonary vein
- expanded pectoral and pelvic girdle
- ventrally oriented ribs that eventually surrounded lungs
- flattened skull with eyes on top of the head
- spinal column strengthened
- cervical vertebrae (neck) so head moves independetly from body
- development of choanae
- jaw modifications to change from sucking methods
- operculum and gills lost
- caudal fin reduced, lateral line lost
- sensory, physiological and behavioural changes
- —-vision, hearing, gas exchange, water balance, navigation, movement, reproduction
amphibian characteristics (6)
- moist environments
- lay eggs in water
- hatch to an aquatic juvenile phase
- undergo metamorphosis to adult form
- think skin (mucus glands, cutaneous respiration in some)
- breath using buccal force pump
air intake steps in frogs (buccal pump)
- glottis closed and the floor of the cavity lowered, Air enters pocket of buccal cavity
- glottis opens, lung volume is reduced, air forces out of the lungs and out of the mouth and nares
- mouth and nares close, floor of buccal cavity rises, air is pushed into lungs
- glottis closes, gas exchange occurs in lungs
what is an amnion?
a sack like membrane that holds the developing embryo in a compartment of water
what is an amniote?
a vertebrate whose embryo is wrapped in an amnion
what have amniote?
reptiles, birds and mammals
- amnionic egg with a tough outer shell
- internal development
what is anamniote?
no amnion
amniotic egg
- watertight, will not dry
- chorion (gas exchange), allantois (waste repository), yolk sac (nutrients) and amnion
what is dry skin?
layers of scales that help prevent moisture loss
thoracic breathing
- create a negative pressure
- breathing capacity improved
what are osteostracans? what do they have?
the earliest known vertebrates
- bony plates–> dermal armour
- basis for evolutionary development and diversification of integument
placoderms
- armour broke into smaller unit (denticulated cosmoid scales)
- evolution of teeth from scales in mouth (allowed lifestyle, habitat diversification
what is integument?
the largest organ with many varied structures including the skin, hair & associated glands
what are the functions of the integument?
- interface between organism & development
- sense organ
- some organisms: gas, water & ion exchange, nourish young, vitamin D synthesis, blood pressure regulation
- structural role: helps to hold shape
- protection - injury, barrier to pathogen
- gathers and dissipates heat
- defense
- communication
what are the three layers of the integument from inner to outer?
- hypodermis
- dermis
- epidermis
integument similarities of epidermis across vertebrates
- outer layer
- develops embryonically from ectoderm
- rests on basal lamina
- is over top of the dermis
in many fishes and amphibians what are the similarities across vertebrates in terms of epidermis?
-mucus to moisten skin surface
- prevents skin from drying out & prevents bacterial infection
- ensure laminar flow of H2O across surface
what does the epidermis produce?
hair, feathers, baleen, claws, nails, horns, beaks, some scales
what is the scale formation of the epidermis?
folds in integument
what is the epidermis made of in terrestrial vertebrates?
keratin –> stratum corneum
where is keratin thicker?
in regions of lots of contact (feet)
what are the three epidermal layers
- basal lamina
- stratum germinativum
- other epidermal layers
basal lamina
- non-celllar, extracellular matrix of collagen, proteoglycans etc
stratum germinativum
- cuboidal cells that divide
- epidermal layer on top
other epidermal layers (to surface)
- towards surface, outer layer can be keratinized or cornified–> stratum corneum
what do the other epidermal layers (to surface) arise from?
s.germinativum
how does keratinisation occur?
from friction, abrasion
what is keratinisation of the oral cavity due to?
abrasive/sharp food
does keratinisation occur in fish and aquatic animals
no
where is the dermis located?
under the epidermis
what does the dermis contain?
- connective tissue, mostly collagen with eslastin woven into layers (plies)
what is thicker the dermis or epidermis and why?
dermis because it is mature skin with two layers: stratum laxum and stratum compactum
what might the dermis als contain?
macrophages, chromatophores- neural origin, pigment cells, nerve endings & sense organs, blood vessels
what brings blood vessels close to the body surface?
dermal papillae
in fishes and aquatic animals how is dermis arranged?
orderly plies: form stratum compactum, elastic nature
in terrestrial vertebrates how is dermis arranged?
- more irregular arrangement
- rely on limbs, less on trunk
where is the hypodermis located?
- between dermis and muscle layers
- between skin and deep body musculature
what is the hypodermis made out of?
loose connective and adipose tissue
what did the interaction between the epidermis and dermis give rise to?
specialization and derivations
what skin appendages did the interaction between epidermis and dermis give rise to?
- hair & fur
- feathers
- teeth
- scales
- nails and claws
- mammary glands
- sweat glands
fish integument
- covered by mucus
——secreted by glands in the skin
——-important bc it inhibits entrance of pathogens (parasites), slight antibacterial action, and reduces friction when swimming - epidermis alive and active on body surface (no layer of dead, keratinized cells)
- scales of dermal origin
what are the two types of epidermis cells in fish integument?
-club cell
- granular cell
- goblet cell
- sacciform cell
dermis in fish integument
- collagen
- may be elastic
- dermal bone
- scale surface often covered by enamel & deeper layer of dentin
bony fish dermis
- 2 layers
- loose connective tissue & dense fibrous connective tissue
- chromatophores
bony fish epidermis
- basal layer of cells
- above- stratified epidermal cells
spines
- enlargement of single scale
- no joints
- often have poison glands associated with spine
what are photophores?
light generating glands
two types of photophores?
- secretions nourish bacteria
- chemical reactions to produce light
what are some examples of bacterial photophores?
fish, few squid, pyrosoma (tunicate)
how do bacterial photophores work?
in specialized organs, providing nutrients potentially continuous luminescence
examples of fish that have bacterial photophores?
anglerfish, pinecone fish, lantern eyes/flashlightfish, ponyfishes/slipmouths, and ichthyococcus
how do fishes control bioluminescence?
- they have a lid that covers the organ
- rotation of organ
- vascular control: control blood supply to light organ (o2 decreases light intensity decreases)
bioluminescence in splitfin flashlightfish
- suborbital light organ
——-cavity under the eye
how does the suborbital light organ work in flashlightfish?
symbiotic bacteria produce bluish light enhanced by a reflective inside surface (blink up to 90 times per min)
photoblepheron (flashlight fish)
lid slides up to cover organ when not being used
anomalops (flashlight fish)
rotate the photophore
phathanophaneron (flashlight fish)
combination–> rotates and slides up over the organ
what are the purposes of the suborbital light organ
- light assist in predation (see or attract prey)
- avoid predatory fishes (blink-and-run pattern)
- intraspecific communication (schooling, territorial, courtship behaviours, reproductive advantage, species recognition)
