BIOL232Z: Comparative Zoology Flashcards
Bryozoa - Moss Animals
~6,000 described species
-sessile
-coelomate
-no circulatory system or excretory organs
-hermaphrodites or gonochorric
-live together, create colonies
Hermaphrodite
Have both male and female reproductive organs
Gonochorric
Either male or female
Brachiopoda - Lamp Shells
~400 living species
- sessile
-coelomate
-simple gut, open circulatory system and excretory system
-Gonochorric
-ventral and dorsal valves
-pedical
pedicle
attach and anchor individual to substrate
Annelida - Segmented worms
~2,000 living species
-Bilateral
-Metameric and segmented
-coelomate
-circular and longitude muscles
-hydroskeleton
-specialised digestive system, closed circulatory, ventral nervous cord
Hydroskeleton
A flexible skeleton supported by fluid pressure
annelida movement
-longitudinal muscles contracted, segment shortens
-circular muscles contracted, segment stretches and elongates
-muscles along gut to aid in digestion
Annelida - reproduction, development and larvae
-asexually by budding out of centre or posterior of body
-planktotrophic trochophore larvae
Mollusca - snails, slugs, octopuses and cephalopods
~80,000-200,000 species
-typically bilateral
-coelomate
-complex gut, kidneys, heart, nervous system, open circulatory system
-mantle has shell glands that excrete calcareous shell
-“Brain” and two nerve cords
-gonochoric or hermaphroditic
Mollusca radula
-part of the mouth
-grating organ used to scrape surface for food
gastropod torsion
-all internal organs rotated
-no longer linear
-anus opens up just behind the head
-some organs that were on the right are now on the left
Arthropoda
> 80% of described animal species
-Bilateral, metameric
-Segmented legs
-Coelomates
-complex regionalised gut, open circulatory system, complex nervous system
-gonochoric
-Exoskeleton with sclerites
-growth by moulting
arthropoda - miriapoda
-many feet
-centipedes and millipedes
-differentiated by legs per segment
Arthropoda - Crustacea
-cephalothorax and abdomen
-carapace covering cephalothorax
-malacostracan tail fin
Arthropoda - Chelicerata
-prosoma and opistosome
-modified appendixes : chelicera and pedipalps
-8 legs
Arthropoda - Hexapoda
-head, thorax, abdomen
-antennae, anntenulae
-six legs, on second and third segments
-wings (not appendixes)
Echinoderma
~7,000 living species
-marine
-pentagonal symmetry
-coelomates, deutrostomes
-water vascular system
-calcareous endoskeleton
-gonochorric
-5 side symmetry
Chordata
~3,000 species (lancelets and tunicates)
-Marine
-bilateral
-coelomates, deutrostomes
-dorsal nerve chord, specialised gut , circulatory system with heart
-gonochorric or hermaphroditic
cephalochordates
-lancelets
-notochord
urochordates
-tunicates
-notochord doesn’t go into the head
-larvae looks like a tadpole
comparative digestive systems
-flatworm: incomplete digestion
-nematode: complete digestion
Spherical
Any plane passing
through the centre divides the organism into halves
Radial
Body parts are arranged radially around a central oral-aboral axis
Bilateral
A single plane, the mid-sagittal plane, divides the body into halves
Gastrulation
rearrangement of
blasters and formation of the
embryonic germ layers
germ layers
-ectoderm (“outside”),
-mesoderm (“in the middle”)
-endoderm (“inside”)
Protostomes
-(“mouth first”)
-mouth develops from the blastopore
Deuterostomes
-(“secondary mouth”)
blastopore gives origin to the anus, the mouth forms secondarily
Porifera - sponges
~9,000 species
-aquatic, sessile
-no gut, muscles or nerves
-no mucus layer
-can be dissociated (broken apart and then reform original shape)
Cnidaria - jellies, corals, anemones
~11,000 species
-aquatic
-swimming Medusozoa or sessile Anthozoa
-lack CNS, discrete organs for respiration, digestion, excretion
-Cnidocytes: specialized cells used for
capturing prey
-Hermaphroditic, gonochoristic
Platyhelminthes - flat worms
~100,000 species
-bilateral, not metameric
-acoelomate
-no skeleton
-incomplete digestive system, no circulatory or digestive organs
-fission/regeneration, gonochoric, hermaphrodites
Nematoda
~30,000 described species
* size: μm to m
* bilateral
* pseudo-coelomate
* hydro-skeleton + external collagen cuticle
* no circulatory system or respiratory organs
* only longitudinal muscles
* Complete digestive system
Nematoda reproduction
- Rare asexual reproduction (parthenogenesis)
- gonochoric
- very few hermaphrodites
- Moulting (“larval” stages)
Gnathifera (incl. Rotifera)
- Seisonidea
- Monogononta
- Digononta (Bdelloidea)
- Acanthocephala
Rotifera
-bilateral
-pseudo-coelomate
-hydro-skeleton +
intracellular lamina
-no circulatory or respiratory system
Gastrotricha
~30,000 described species
-bilateral
-A/pseudo-coelomate
-Freshwater and marine
-Complete digestive system
-Head with brain and sensory organs
-Ventral cilia used to move
-Hermaphrodites or parthenogenetic
Tardigrada
-bilateral, “metameric”
-hydro-skeleton +
chitinous external cuticle
-pseudo-coelomate
-no circulatory system or
respiratory organs
-moulting
Rotifera and Tardigrada - special characteristics
Dormancy
-Diapause, e.g. resting eggs
-Quiescence, e.g. cryptobiosis
Dorsal
balance/stabilization, sudden direction changes
Pectoral
paired fins, directional changes, aid swimming and directional changes
Pelvic
deceleration
Anal fin
stabilization
Heterocercal caudal fin
sharks, sturgeons, paddlefish
Homocercal caudal fin
nearly all bony fishes
Rounded (Caudal Fin)
effective acceleration/maneuvering, but high drag, not found in fish that swim long distance
Truncated (Caudal Fin)
straight edge, effective for rapid turning and short bursts of speed
* Emarginated – low drag, two lobes
Emarginated (Caudal Fin)
low drag, two lobes
Forked (Caudal Fin)
reduction in turbulence, 2 lobes
Lunate (Caudal Fin)
maintain high speed, efficient/low drag
Sagitiform body shape
elongated, tubular body layout, arrow‐shaped (ambush predators)
Depressiform body shape
wide, flat (bottom dwelling)
Compressiform body shape
laterally compressed, tall/thin body, allow for quick movement/turning (enter vertical crevices for refuge)
Fusiform body shape
streamlined, pointy ends (plane‐shaped), low frictional resistance for extremely fast movement
Anguilliform body shape
long, thin, snake‐like (permit navigation of narrow refuges and reduce drag)
Globiform body shape
round/globe‐shaped
Taeniform body shape
ribbon‐shaped (crevices & narrow refuges)
Agnatha
Jawless, comprises hagfish and lampreys
Chondrichthyes
-Sharks, rays (Subclass Elasmobranchii) and close relatives
-Jawed fish, cartilaginous skeleton, lack swim bladder
-Teeth on a conveyor belt
-Sense of smell ‐ 1/1,000,000, nostrils (solely) for olfaction
Lateral line
line of nerves (neuromasts) that sense ‘particle motion’ –
Physical movement of water, vibration, pressure gradients
Ampullae of Lorenzini
electro sense
elasmobranchs reproductive strategy
-Produce fewer, more mature offspring (K – selection evolutionary strategies)
-Take a long time to reach sexual maturity
-Most fertilize eggs internally
-Some are ovoviviparous (egg’s hatch in mother’s body)
special features of rays
-Anatomy adapted for life on seafloor or in midwater
-Pectoral fins evolved into ‘wings’, fused with head
-Many bones fused for greater rigidity
-Modified tail for defense (whips/barbs)
-Manta rays can exceed 8 meters laterally
Osteichthyes
-Skeleton composed of bone
-More species than all other vertebrates combined (>23,000)
-Most control buoyancy by adding/releasing gas to/from swim bladder
-Homocercal tail
-Bony scales to protect body (typically ctenoid or cycloid)
ray-finned fishes reproduction
-More diversity in reproductive biology than any other vertebrate taxa
-Tend to produce many more offspring, with less investment (r – selection evolutionary strategies)
-Most species are oviparous (eggs are laid with little or no embryonic development within mother)
-Most fertilize eggs externally
mammalian/synapsid adaptations
-Upright posture (specialized vertebrae)
-Specialized teeth
-Ear bones
-Endothermy
-Lactation
-Locomotion and lung ventilation
“Thermogenic opportunity” model
-Basal mammals were nocturnal
-Cold nights meant endothermy was essential to survive
“Warmer is better” model
-Biochemical/physiological processes operate faster
-Increases competitiveness/strength/speed etc.
“Aerobic scope” model
-More activity requires higher rates of metabolism -> evidence for selective pressure on increased locomotion in ancestral mammals
-Increase in metabolic rate must be accompanied by increase in resting rate, and hence internal heat production
“Parental care” model
-Increases rate of embryonic development – less time until they are independent
-Increases viability of embryos
Evolution of mammals – lactation
-Liquid diet allows jaw to grow
-Permanent teeth can then erupt in adult-
sized jaw
-Allows production of offspring to be separated from seasonal food supply (c.f. birds)
-Allows young to be small relative to parent
Locomotion and ventilation
-Earlier amniotes: sprawling posture, short limbs
-Later synapsids – limbs under body, less bending of trunk
modern mammals
Prototheria
-Monotremes
Theria
-Metatheria (marsupials)
- Eutheria (placentals)
Monotremes
-Mono = one, trema = hole
-Cloaca for reproduction and excretion
-Lay eggs – presumably the ancestral mammalian condition
-Two families:
-Ornithorhynchidae
-Tachyglossidae
monotremes characteristics
-Sprawling stance like earlier amniotes
-Lack teeth as adults
-Produce milk, but have no nipples
-No placenta
Marsupials
-Have a (less extensive) placenta than eutherians
-Produce small live young that (in most species)
mature in a pouch
-Split between new world and Australian groups
-Plus extinct group that inhabited Asia
Eutherian (placental mammals)
-Two major clades –
-Atlantogeneta
-Boreoeutheria
-Nourish young with a placenta
-Enormous diversity
Abduction
a motion that pulls a structure or part away from the midline of the body
Adduction
a motion that pulls a structure or part towards the midline of the body
Locomotion – Skeletal changes
-Epipubic bones are present in monotremes and marsupials
-The position of the limbs in monotremes is more abducted than in therians
-In therians, the position of the limbs is more adducted
kangaroo locomotion
a) Tail provides propulsion
b) Weight bearing is hind limbs
c) Power
Locomotion – Flight
-Bats the only mammal that flies – the rest glide
-Over 1400 species
-Evolved about 65mya
-Short and broad wings in cluttered environment, long and narrow in the open
-Reduced mineralisation in bones
Feeding – Teeth
-Herbivore teeth adapted for grinding
-Omnivore teeth need to grind and shear
-Canines may be used to stab prey in carnivores
Carnivore adaptation, skull and teeth
-A large temporalis muscle is typical of carnivores, with a forceful bite
-Have enlarged canines and specialises molars
reproduction
-marsupial young are altricial, only leave pouch when larger
-Primates, rodents, felids, canids are altricial
-Cetaceans, ungulates are precocial
gymnophiona
213 species
caudata
728 species
anura
-7150 species
-external fertilisation
-radical metamorphosis
-aposematic
-secrete lipophilic alkaloid toxins
caecilians
-213 species
-35 genera
-10 families
-mostly fossorial, some aquatic
fossorial
adapted for burrowing
neoteny in salamanders
-retention of larval characteristics in mature adults
-advantageous in productive and stable habitats
-Selected for where low temperature constrains full metamorphosis
reptiles
-27 crocodiles
-360 turtles
-1 tuatara
-11,302 squamates
turtles
-Marine species can dive up to 500 m
-upland species can live with less than 10 cm of rainfall a year
-slow growth, late maturity, repeated reproduction and late life
-oviparous
crocodiles
-Internal fertilization
-Oviparous
-secondary palate
-Males communicate with audible vocalizations and subsonic vibrations
Temperature – Dependent Sex Determination
-sex is determined by incubation temperature during a
brief but specific stage of embryogenesis
-e.g. crocodilians, turtles and some lizards
tuatara
-Sister to Squamata
-Most species were outcompeted by lizards in
the Cretaceous
-Only species that survives is in New Zealand
-survives to low temperatures
-Long lived
Squamata (Lizards)
-11,302 species
-Some are elongated and limbless
squamata parietal eye
-3rd eye
-has a retina, lens and nerve endings
-used for circadian rhythms
-lost in snakes and some lizards
Parthenogenesis
- Reproduction by females without fertilization
- These are diploid, sometimes triploid
- Once a parthenogenetic species is established it doubles its reproductive potential
- Also occur in some snakes
squamata (Snakes)
-3956 species
-Possible evolution from a nocturnal semi-burrowing lineage of lizards
what is a dinosaur
-two holes in skull (diapsid)
-legs under the body
-oviparous
-terrestrial
-had epipophyses
diplodocus
-lots of air spaces in structure of neck to make it lighter
-acted as accessory pumps going up the neck, assist in pumping blood to the brain
dinosaur temperature regulation
-probably mesothermic
-could regulate their body temperature but didn’t do it all the time
jurassic coast
189-199 mya
Epipophyses
backward-pointing ‘ribs’ from the vertebrae
dinosaur bones: what do they tell us
-Sauropod necks pneumatized = nice and light
-Motion: swaying, cervical ribs as shock absorbers
-Plod: compress muscles: squeezes air sacs around the vertebral artery = accessory pumps maintain blood pressure
main groups of birds
-Paleognathae (ratites and tinamous)
-Neognathae – split into Galloanserae (chicken, ducks) and Neoaves (95% of extant species)
birds respiratory system
-Air sacs
-Two respiratory cycles to move one unit of ‘breath’
-One-way passage of air
-Lots of ‘air capillaries’
-Allows birds to breathe at high elevations
-Efficient
adaptations to flight
-Hollow bones to reduce weight
-Air filled bones
-Lower centre of gravity
-Enlarged sternum
-Extended scapula (shoulder bone)
-Fused clavicle (collarbone)
-Fused leg bones
-Small pygostyle (tail bone)
flight muscles
-Contracting pectoralis produces down stroke
-Supracoracoideus produces upstroke
-Ratio of two muscles can be from 3:1 to 20:1
-Weight of muscles can be up to 25% body weight
feather structure
-Simple chemical structure – beta-keratin + lipids/water/pigment
-Contour feathers streamlined, strong through barbule structure
-Many feather types e.g. down, plumes, bristles
-Protect against temperature extremes, water, sun
Mechanics of Flight
-Inner wing stays rigid produces lift through aerodynamic properties
-Outer wing can move to provide thrust
-Tail provides lift, drag, stability and manoeuvrability
Aspect ratio
length/area (long narrow will have high aspect ratio)
Wing loading
weight of bird/wing area (small wings to body is high loading)
Ability to change outer wing shape
manoeuvrability
bird Locomotion on the ground
-Hopping and walking in terrestrial birds
-Runners have long thin legs
-Feet used for locomotion and catching prey in many species
-Trade off between speed on land and in air
beak
-consists of bones that form mandibles
-surafce of bones covered with modified integument ‘rhamphotheca’
-dermis contains sensory receptors
crop
temporary food storage for feeding chicks and storing extra
-In doves and pigeons crop produces ‘milk’ for young
stomach
size related to diet, carnivore stores easily digestible material, herbivores muscles to breakdown food
Proventrilicus
secretes digestive enzymes and acid (large in fruit eaters)
gizzard
muscular, includes small stones to break down food
Small intestine
Enzymes for food breakdown
Large intestine
absorption of water and electrolytes
Cloaca
stores waste while water reabsorbed
birds development of young
-Altricial likely to need two parents
-Precocial one parent
-Most birds have altricial young
-Evolution of polygamy more likely with precocial young
altricial
-Fed in nest
-Eyes closed at hatching
-No feathers
precocial
-Downy plumage
-locomotor activity
-Follow parents
-May search for food and feed alone
environmental odours
-Locate desirable items (food, water, nesting sites, etc.)
-Avoid dangers (fire, etc.).
-Prey localization,
-Homing
-Territorial marking
-Predator deterrence and avoidance
-Pollination
pheromones
-Sex attractants,
-Identity of individuals,
-Social status,
-Social group, and place,
-Aggregation - mediate feeding, sex, and aggression;
-Dispersion - maintain individual spacing
-Reproductive - trigger courtship displays and postures
pheromones mechanism
-individuals in social groups will often give off a group odour
-dogs roll in fox poo to smell like their environment
olfaction
chemo-sensation
odour receptors
reside in an epithelium interspersed with supporting cells.
Aqueous fluid
separates the membrane from environmental chemicals - which reflects the evolutionary origin of these systems in a marine environment
vertebrate olfaction
-birds, sharks and amphibians, quite a small area of the brain for scent
-number of genes involved in receptors determines how well they can smell
dogs olfaction
-volmeronasal organ: specific to dogs, allows them to process pheromones
-short nosed dogs can’t smell well due to less room for receptors
Invertebrate olfaction
-Bipolar neurons
-Neurons extend a thin dendrite to the environmental interface
-Recognition begins with the interaction of odour with odorant receptors on the dendritic
vertebrate olfactory systems
The main olfactory system (MOS) and the accessory olfactory system (AOS)
Vomeronasal organ (VNO)
-Part of the accessory olfactory system
-Involved in perception of pheromones
-Opens into to the nasal cavity.
-Present in most tetrapods - first seen in amphibians
Vertebrate olfaction: Birds
-Small olfactory bulb in general
-uropygial gland produces preen oil that can differ seasonally and between sexes
-Pigeons use olfaction in homing
Vertebrate olfaction: Kiwi
-Kiwis highly developed and functional olfactory system
-Kiwi’s olfactory bulb is the second largest among all birds relative to the size of its forebrain
-‘Nose’ at the end of the beak unlike other birds
Electrosense
-Modified hair cells in the lateral line of some fish detect electric currents in water
-used for communication, prey detection or navigating
ampullae of Lorenzini
-Sharks and rays
-jelly-filled canals detect differences in voltage between the opening of the canal and the electroreceptors
-detect prey and navigate using the earth’s magnetic field
Nervous system variation
-Hydras have neurons arranged in nerve nets
-Sea stars have nerves projecting into each arm connecting to a central ring
-Bilateral organisms have central ganglia
Nervous system: CNS
-CNS occurs only in bilateria, although not in all bilateral animals
-More developed inverts, show a more complex nervous system and the development of brains in the animals’ rostral part.
-An insect’s brain is a complex of six fused ganglia (three pairs) located dorsally within the head capsule.
ENS
-Enteric Nervous System found across invertebrates and vertebrates
-ENS occurs in all animals investigated, including hydra, echinoderms and hemichordates that don’t have a CNS
arthropod CNS
-The nervous system of an arthropod consists of specialized cells - neurons
-Arthropod CNS is segmented and can be roughly divided into the brain and the ventral nerve cord
The Brain evolution
-Larger brain reduced rate of growth and reproduction
-probable limit on brain size
Cephalopods
-Elaborate sense organs and nervous system
-Well developed eyes
-High visual acuity, but unlikely to see colours
-No blind spot
-Brain has lobes may be comparable to cerebellum and frontal lobes in vertebrates
-Rarely live for more than 2 years
squid
-smaller brain
-complex clusters of nerves
-vertical and optical lobes, like octopus
Octopus
-Brain-to-body ratio is the largest of any invertebrate
-Have about as many neurons as a dog
-Each arm has its own mini brain plus a central brain
-Brain has almost 40 different lobes
-Arms can act independently
-Chromatophores, for changing colour
coelomate
internal cavity separated by organs with peritoneal lining
