Vertebrates 1 Flashcards
Approximately … of animals are vertebrates
1%
Around half of vertebrates are … and half are …
amniotes, fish (mainly actinopterygiii)
The amniotes and the non-amniotes separated in the…
late Devonian
How many orders of mammals are there?
27
How many orders of birds are there?
41
How many reptile orders are there?
4
How many amphibian orders are there?
3
There is … wherever you look on the phylogenetic tree
asymmetry
- e.g numbers of orders, number of species within each order or group (half of all bird species are passerines yet this is only 1 of 41 orders)
550MYA there were…
separate continents
300MYA there was…
one single continent called pangaea, formed from the merging of other continents through continental drift - pangaea is the main birthplace of terrestrial vertebrates
150MYA…
pangaea broke apart
The number of vertebrate species reached a maximum around…
12 million years ago
What is the smallest vertebrate?
Paedophryne amauensis - 7mm long frog
What is the largest vertebrate?
Blue whale - 33m
What depth have snailfish been found at?
8000m
Barheaded geese have been seen flying…
over the Himalayas at over 8000m of altitude
What is the fastest reproducing vertebrate?
Killifish - life cycle takes 2 weeks
… animals are usually vertebrates as an … … existence requires different feeding modes
large, energetically expensive
Most vertebrates … … whereas some … … to … …
lay eggs, give birth, live young
Vertebrates play important … roles, and are often at the … of most … chains
ecological, top, food
We know much more about vertebrates than invertebrates as they have been studied more for longer.
Correct
Give an e.g. of convergent evolution (analagous characteristics)
Shark, ichthyosaur, dolphin
Give an example of divergent evolution (homologous characteristics)
Human hand, horse hoof, dolphin fin, bat wing
For each living species of vertebrate there may be as many as … extinct species
100
Approximately … of vertebrate species are endangered
20%
What is an endostyle?
structure on floor of pharynx for producing mucus for filter feeding - believed to be homologous to thyroid gland in vertebrates
Larval stage lampreys are..
filter feeders (endostyle becomes thyroid gland in adult)
What makes vertebrates different from invertebrate chordates?
- Presence of vertebrae (usually replace notochord - notochord reduced to discs between vertebrae) - although lampreys and hagfish don’t have fully formed vertebrae, but instead have rudiments (arcualia)
+ Cranium (bony, cartilaginous or fibrous) - with vertebrae makes up endoskeleton - Duplication of hox gene complex (homeobox genes) 0 several duplication events
- Development of neural crest (neural crest cells are migratory and multipotent - responsible for new structures, especially in head - could be considered another germ layer, making vertebrates quadroblastic)
- Placodes (give rise to complex sense organs)
- Brain of vertebrates larger + has 3 parts
Gnathostomes have vertebrae that…
grow around the vertebral column
Vertebrates have increased body size and increased activity. Cephalochordates are up to 10cm long, whereas jawless vertebrates are 10-100cm long. Therefore they can’t rely on … action or …, to achieve the energy required for their higher … …. They have also evolved the ability to sustain periods of … … which can allow bursts of activity
ciliary, diffusion, metabolic rates, anaerobic respiration
Vertebrates also have … tissues, whereas non-vertebrate chordates don’t. For example, bones are strengthened by the unique mineral … (calcium and phosphorous), which is more resistant to … acid after … respiration. Mineralised tissues are made up of … fibres, … tissue matrix and hydroxyapatite, allowing hardness, protection, and flexibility of lightweight materials
Mineralised, hydroxyapatite, lactic, anaerobic, collagen, proteinaceous
… types of tissues can be mineralised. These are…
six
- mineralised cartilage
- bone (highly vascularised so can repair itself) - 2 types: dermal (in skin) and endochondral (inside - requires unmineralised cartilage framework to form)
- enamel, enameloid and dentine (teeth, exoskeleton, dermal scales of cartilaginous fishes)
- cementum (fastens teeth in sockets)
Bone and mineralised cartilage are … mineralised
70%
At the start of vertebrate evolution there are no … tissues. Basic units of this tissue are found in early vertebrates called …, e.g. the … armour of …
mineralised, odontodes (dermal), dermal, ostracoderms
Ostracoderms are an extinct group of … vertebrates
jawless
Bones are thought to be … in origin
dermal (in the skin)
What are the enamel structures on the skin of sharks called?
Denticles
Jawless vertebrates (e.g. hagfish and lamprey) have … endoskeletons
unmneralised
Why did mineralised tissues evolve?
- Defensive structure
- Protected electroreceptors
- Storage/regulation of phosphorous and calcium
What is the group found 500MYA that was for a while though to be the earliest vertebrate group?
Conodonts (with teeth-like structures in pharynx)
What is now thought to be the earliest vertebrate?
Myllokunmingia - 530MYA - had skull and skeletal elements made of cartilage
+ haikouichthys
It is believed that the earliest vertebrates originated in a … environment
marine
- paleontological evidence (fossils in marine deposits)
- comparative physiology (invert chordates + other deuterostomes are marine with isotonic body fluids to marine water + so are hagfish)
Some ostracoderms evolved a … fin and … fins such as
dorsal, paired (pectoral)
The present day agnathans (hagfishes and lampreys) are in the group …
cyclostomes
- don’t have any mineralised tissues
All vertebrates except jawless vertebrates show…
alpha/beta split of haemoglobin globins (which occured 500MYA
- the common ancestor of hagfish and lampreys predates this split so they diverged before this
Most lampreys are … and have teeth made of … rather than mineralised tissues. They use a … tongue to grind tissues and take them up with blood. They also produce an …
predacious, keratin (a protein), rasping, anticoagulant
lampreys display … ventilation through their gill slits as they cant pass water through their mouth when latched onto prey
tidal
- not particularly efficient
Which part of a lamprey’s anatomy prevents water flowing back into the mouth?
Velum
Lamprey’s retain their … throughout their life and their vertebrae are minute …
notochord, arcualia
Lamprey’s have a single … connected to the anterior …
nostril, pituitary
Lamprey larvae are … …
filter feeders
Many lampreys spend their adult life in the … and return to … to breed, meaning they are ….
sea, freshwater, anadromous
Lampreys find streams by following … released by …
pheromones (bile acids), larvae
- detected at low concentrations and produced in large quantities
Some lampreys became landlocked so complete their life cycles in freshwater … … (USA)
great lakes (in the 1920s)
What are the 3 british species of lamprey?
Brook lamprey (doesn’t feed as adult)
River lamprey
Sea lamprey
Hagfishes are generally regarded as … and may use slime to help them catch prey as they may potentially be predacious
scavengers
Hagfish can acquire nutrients….
through their skin and gills and tolerate anaerobic conditions in carcasses
Hagfish don’t have a … fin but do have a … fin
dorsal, caudal
Hagfish are the only vertebrates with blood…
isosmotic to the sea
Hagfish have very small … with skin over them. Other senses are more important, and they have organs such as … for this
eyes, barbels
Hagfish have a … biased sex ratio
female
Hagfish dont have a … …
stage
Hagfish … themselves in … to pull food off carcasses
tie, knots
What are the jawed vertebrates known as?
The gnathostomes
The jaw evolved from the … … … (… …)
anterior branchial arch (mandibular arch)
What supports the jaw?
Hyoid arch (this becomes part of the jaw in later gnathostomes such as the sharks
It is thought that the arch enlargement (which lead to the evolution of the jaw) first…
aided ventilation rather than feeding, as it functioned in closing and opening the entrance to the pharynx
- facilitated more active lifestyle
However, the mandibular arch doesn’t form a … … … in any living vertebrate or fossil and has different … to the rest of the gill arches
functional gill arch, development
It is thought that … had to evolve before the jaw could evolve as too much space was taken up with …
diplorhiny, monorhiny
Which fins control pitch?
Pelvic and pectoral
Which fins control yaw?
dorsal and anal
The genes responsible for the dorsal fin of the lamprey are also responsible for..
the midline and paired fins in bony fishes (same genetic mechanism in different location) - these same genes control limb development in the tetrapods
The evolution with the gnathostomes coincided with the … of the … … complex
duplication, hox gene
Gnathostomes have two … …
olfactory bulbs
When did the placoderms (plated fish) exist?
430-360MYA
What did male placoderms have?
Claspers - for reproduction - believe where internal fertilisation in vertebrates originated - viviparity also found (birth to live young)
- (in cartilaginous fish - modified fins used as intromittent organ instead)
What are the acanthodians?
Extinct “spiny sharks” - no armour plating but denticle-like structures like on chondrichthyes (likely related group)
Chondrichthyes appeared around … and they have a … skeleton which can be …. They have a … filled liver and high blood … concentration for …
400MYA, cartilaginous, mineralised, lipid, urea, buoyancy
Most chondrichthyes have … jaw suspension, meaning the mandibular arch is suspended from the … rather than being fused, using the … arch. This allows them to protrude and retract their jaw.
hyostylic, cranium, hyoid
What are the groups of cartilaginous fishes?
- Holocephalans (e.g. Chimaera) - live in deep water and have holostylic jaw suspension instead of hyostylic - some have toxic spines and proboscis for electrical reception
- Elasmobranchs (sharks, skates and rays)
What are the distinctive features of the sharks (galeomorphs w/ anal fin and squalomorphs w/ no anal fin)?
blurgh
The skates and rays (batoidea) have enlarged … … and a … (remains of first gill pouch)
pectoral fin, spiracle
What is the difference between a skate and a ray?
skates have dorsal fins on tails, skates lay eggs, rays give birth to live young
Some rays have modified gill muscles which can…
produce an electric charge to stun prey (skates can produce weaker electric currents to stun prey)
Manta rays have … fins used for channeling water in … …
cephalic, filter feeding
Chondrichthyes have a … tail
heterocercal (may be used to give lift as don’t have swim bladder and they are heavy-bodied animals)
Chondrichthyes guts have … valves and are relatively short
spiral
Denticles improve …
hydrodynamics
The stingray barb is a modified …
denticle
Skates have denticles only…
along their midline
Shark teeth form within their … and form a tooth … that rests on their jaw
skin, whorl
Many sharks kill mammalian prey by … (blood loss), and having this tooth arrangement aids in this
exsanguination
Cartilaginous fishes have lots of … investment, which may be a reason for their success, as well as their advanced sensory systems
parental
Cartilaginous fish sensory systems:
- mechanoreceptors (neuromast organs/lateral line detect vibrations)
- Chemoreceptors (acute sense of smell - 1 pt in 10bn) - turn to stimulated side first
- electroreceptors (ampullary organs - in heads of sharks and pectoral fins of rays - detect muscle impulses of prey)
shark vision is developed for…
low light intensities (rod rich retina, cells with crystals of guanine for picking up light)
Sharks have proportionally heavier..
brains than other fishes (brain to body ratio similar to some tetrapods)
Male sharks have modified … fins called … for reproduction
pelvic, claspers
- may have hooks and barbs to ensure sperm transfer
Lecithotrophy means…
no nutrition other than yolk (which would be matrotrophy)
How do viviparous sharks feed their young?
- some secrete substances (uterine fluid)
- some ovulate to feed young
- some have yolk sac placenta
Once sharks are born or eggs are laid there is…
no parental care
Which group represents over 95% of all fish, with over 32,000 species?
Osteichthyes
What are the 2 groups of osteichthyes?
Actinopterygiii and Sarcopterygiii
The first osteichthyes fossils date back to around…
400MYA (radiation in devonian)
Give examples of non-teleost actinopterygiii
sturgeon, paddlefish
Sturgeon have scales reduced to thicker … and have secondarily lost …
scutes, bone (so have cartilaginous skeleton)
Paddlefish paddles detect …
electrical impulses (have ampullary organs like sharks)
Teleosts have specialisation of feeding mechanisms. A large reason for this is the … of the bones in their skull and jaws, allowing them to exploit a wide range of prey. The volume of the … … is increased, creating suction.
flexibility, buccal cavity
Another teleost feature is … jaws, which come from modified gill arches and help … …
pharyngeal, process food
- may account for diversity in diet
Moray eels have a … pharyngeal jaw, which can be extruded from the mouth
raptorial
What does the lateral line detect?
mechanical cues (water displacement) - often fish have neuromasts in head as well (or instead of in shoals often)
Teleosts have a … tail, … scales, and a … shape. Most are …
homocercal, small, fusiform, oviparous (lay eggs)
Bony fishes have a … … for buoyancy, which is an outpocketing of the …. This is homologous to …
swim bladder, gut, lungs (in lungfish and tetrapods)
If a fish’s swim bladder is connected to its gut, it regulates the air in it by…
coming up for air and burping air out
If a fish’s swim bladder is not connected to its gut, it regulates the air in it by…
secreting and depositing gases from and to the blood supply
The gills of teleosts are covered by an …
operculum
Some species can’t use muscular action to draw water into the buccal cavity and over the gills. Instead they…
swim with their mouth open, called ram ventilation
- often in fast swimming fish such as tuna
What is regional heterothermy?
When fish warm up certain areas of their body (muscles) so they are more effective (at swimming)
Some teleosts require additional gaseous exchange to that they get from their gills, for example….
anabantid fishes, which are obligate air breathers (they have organ called labirynth organ)
Eels migrate from freshwater to the sea to spawn. This makes them …
catadramous
What are the groups in the sarcopterygians?
Lungfishes (3 genera) and coelacanths + those that gave rise to the tetrapods. Lungfish more closely related to tetrapods than coelacanth
Lungfish have both … and …. Australian lungfish have relatively well-developed … as they live in more … water bodies. African and South American lungfish are more dependent on their …
gills, lungs, fins, permanent, lungs
African lungfish can survive in … in … for several years, keeping itself moist using …, during dry periods.
burrows, mud, mucus
Coelacanths do have a lung but..
it is filled with fat (for buoyancy)
