Lab 8 Flashcards
What are the Subphyla of Chordata
Vertebrata
Cephalochordata
Urochordata
What are the 4 features of Chordata
- Notochord
- Pharyngeal slits
- Dorsal, hollow nerve cord
- muscular, postanal tail
what are the 8 clades of vertebrate
- Myxini (hagfish)
-Petromyzontida (lampreys) - Chondrichthyes (Sharks and rays)
- Actinopterygii (bony, ray-finned fishes)
- Sarcopterygii (bony, lobe-finned fishes)
- Amphibia (amphibians)
- Reptilia (including Aves, birds)
- Mammalia (mammals)
what are the 6 informal groups of vertebrates
- Cyclostomes: Vertebrates with no jaws but a circular mouth
- Gnathostomes: vertebrates with jaws
- Osteichthyans: Vertebrates with mineralized bones
- Lobe-finned: vertebrates with fleshy limbs
- Tetrapods: vertebrates with 4 paired limbs
- Amniotes: vertebrates with an amniotic egg (includes reptiles and mammals)
what are the two groups in Cyclostomes
Myxini (hagfish) and Petromyzontida (lampreys)
what are Myxini
- jawless (agnathan)
- no bones - cartilaginous skeleton
- rudimentary vertebrae - notochord for support
- hag fish
What are petromyzontida
- jawless (agnathan)
- no bones - cartilaginous skeleton
- notochord surrounded by flexible sheath with projections related to vertebrae
- most are parasitic
What are Gnathostomes
- “Jaw mouth”
- Jaws
- Includes Chondrichthyes and the Osteichthyans
What is Chondrichthyes
-Cartilage fish, sharks, rays, chimaeras
- primarily cartilaginous skeleton result of secondary loss of bone
- mineralized bone found in some scales, teeth and vertebrae
what are Osteichthyans
- Bony fish
-ossified (mineralized) bone - lungs (or lung derivative)
- include: Actinopterygii and the Sarcopterygii
What are Actniopterygii
- Ray finned fish
- bony rays support fins
- most familiar fish belong to this group
what are Sarcopterygii
- Lobed fin fish
- lobed-fins - pectoral and pelvic fins have rod shaped bones surrounded by thick muscle
- include: Actinistia, Dipnoi, and the tetrapods
What are Actinista
Coelacanths
- thought to be extinct
- found in S. Africa 1938
What are Dipnoi
Lungfish
Have lungs and gills
What are Tetrapods
Vertebrates with four limbs
have digits
Amphibians and amniotes
what are amphibians
- aquatic and terrestrial life stages
- shell-less egg
- Urodela (Tailed ones) Salamanders
- Anura (tail-less ones) frogs and toads
- Apoda (legless ones) caecilians
what are amniotes and the amniotic egg
- Reptiles and mammals
- amniotic egg
- retains water → can be laid in a dry place
Four extraembryonic membranes:
- amnion: protection
- allantois: waste disposal
- chorion (together with allantois): gas exchange
- Yolk sac: covers yolk (nutrients)
what are reptilia
-turtles, lizards, snakes, crocodilians, birds
-young born in shelled eggs or live
- dry skin - keratinized scales
- ectothermy and endothermy (birds)
what is mammalia
- hair
- mammary glands
- endothermy
- teeth with specialized functions
- three groups: monotremes, marsupials, eutherians
what are pharyngeal fish jaws
Many species of fish like the rockfish (Sebastes sp.) have a secondary pair of jaws called Pharyngeal jaws which are used to further process the food and move it from the mouth to the stomach.
what are cat collar bones like
The collar bones of the house cat Felis catus are different from that of humans. Their clavicle is not attached to the other bones of the body. It allows them to narrow their shoulders and squeeze under closed doors or into small spaces.
how do you make a dichotomous key
A dichotomous key is used to identify organisms based on a serious of 2-option choices.
- Paired characteristics must be clearly differentiated
- Use visible features
- Use constant rather than variable characteristics
- Avoid seasonal characteristics or those seen only in the field
- Use measurements rather than terms like ‘large’ and ‘small’
- If possible
- start both choices of a pair with the same word
- start different pairs of choices with different words
what are the synapomorphies of vertebrate
The synapomorphies of Vertebrata are
- Vertebrae, bone or cartilage surrounding the spinal cord
- Bone and cartilage, connective tissues that do support and protection
- Myoglobin, coloured protein in muscle that stores oxygen
- Pineal organ, endocrine gland in the brain that secretes seratonin
How are hagfish and lampreys similar
- Lack of Jaws
Both hagfishes and lampreys are jawless fish, relying on other mechanisms for feeding - Cartilaginous skeletonBoth species lack true bones and have a skeleton made of cartilage
- Absence of ScalesTheir skin is smooth and lacks the scales other fish have
- Single nostrilBoth have a single, midline nostril for olfaction
compare the habitats of hagfish vs lampreys
Hagfish are found in the waters off the coast of the north Pacific.
Sea Lampreys are found in marine environments but spawn in freshwater rivers and streams. They are found in the Atlantic ocean, North American coast, and they also inhabit the eastern North Atlantic and the Baltic, Adriatic, and Mediterranean seas. Freshwater lampreys live in freshwater ecosystems.
compare the habits of hagfish vs lampreys
Habit refers to the characteristic form or morphology of a species.
Lampreys are primitive, jawless fish with eel-like bodies.
Hagfish are scaleless, soft-skinned creatures with paired thick barbels on the end of the snout.
compare the feeding of hagfish vs lampreys
There are plenty of parasitic species which feed on the blood and fluids of fish and other species. They attach to a host and use their circular, suction-cup like mouths, lined with sharp teeth and a rasping tongue. They scrape the skin to create a wound and secrete and anticoagulant to prevent clotting.
Non-parasitic adults do not feed
Hagfish slither into dead or dying animals and out their way out, using their rasping tongue to carry food into their funnel-shaped mouths
how did jaws evolved
Jaws are thought to have evolved from the gill arches, a series of structures in fish that support their gills.
Jaws arose through the simple transformation of an ancestral rostral gill arch.
what did paired fins allow early gnathostomes to do
Early Gnathostomes also evolved paired fins that allowed them to fine-tune their movements. Help balance the animal, keep it level, and prevent it from rolling. May also help with display, protection, and reproduction.
how can you classify fish
Fish can be classified as aquatic, anamniotic, gill-bearing vertebrate animals with swimming fins, and a hard skull, but lacking limbs with digits.
what are the two subclasses of Chondrichthyes
Chondrichthyes have two subclasses: Elasmobranchii includes sharks, rays, skates, and sawfish
Holocephali includes the chimaeras
what are chondrichtyans like
Chondrichthyans have cartilaginous skeleton, ventrally placed mouth, notochord throughout life, operculum does not cover the gills, absence of an air bladder.
Chondrichtyans vary a lot, some are very flat, some have venom, some are bioluminescent, some are really big, and some are very small, some have teeth, some don’t, some live at the bottom of the ocean, some live in freshwater, etc.
what are osteichthhans like morphologically
Osteichthyans have a bone skeleton, paired fins, one pair of gill openings, jaws, and paired nostrils.
Both Actinopterygii and Sarcopterygii are included in Osteichyans due to their shared characteristics and close evolutionary relation.
what traits do Chondrichthyans share with Osteichtyans
Osteichthyes shares a few characteristics with Chondrichthyans
They are generally streamlined, have two-chambered hearts, are poikilothermic, and dioecious. And are primarily aquatic, generally have fins, scales, and teeth.
what are lobe finned fish like
Lobe finned fish differ from ray finned fish as they have fleshy, lobed paired fins, compared to fins supported by thin, elongated bony structures called rays.
The main groups are Actinistia (Coelacanths) and Dipnoi (lungfish) which share the following features:
- lobed fins supported by a central bony axis
- Paired fins with musculature
what are the key characteristics of vertebrates
- Four limbs with digits (fingers and toes), though some may be modified or lost in certain species
- Vertebral column that supports the body against gravity
- Adaptations for breathing air (lungs or modified respiratory systems)
- Modifications to the skull and jaw for terrestrial feeding
what challenges did tetrapods have to deal with while colonizing land
- Support against gravity: Water provided buoyancy, but on land, tetrapods needed stronger bones and muscles to support their body weight
- Risk of desiccation: Living tissues needed protection from drying out in the air, requiring development of protective skin layers
- Respiratory adaptations: Gills were ineffective in air, necessitating the evolution of efficient lungs and new breathing mechanisms
- Reproduction: New strategies were needed for reproduction outside of water, including internal fertilization and protective eggs
- Locomotion: Movement on land required significant modifications to fins, eventually leading to the development of jointed limbs
- Sensory adjustments: Different sensory adaptations were needed for detecting prey, predators, and mates in air versus water
These challenges drove major evolutionary innovations in body structure, physiology, and behaviour that characterize modern terrestrial vertebrates.
what are 6 ways amphibians differ from other tetrapods
- Dual lifestyle: Most amphibians live both in water and on land during different life stages
- Metamorphosis: They undergo dramatic changes from aquatic larvae to terrestrial adults
- Moist skin: Their permeable skin requires them to stay moist and often serves as a supplementary breathing surface
- Reproduction: Most lay unprotected eggs in water, unlike the amniotic eggs of other tetrapods
- Temperature regulation: They are ectothermic and have limited ability to regulate body temperature
- Water dependency: Most species must return to water to reproduce and maintain skin moisture
why are amphibians sensitive to the air and water quality
- Permeable skin: Their thin, highly permeable skin readily absorbs chemicals and pollutants from both water and air directly into their bloodstream
- Dual habitat exposure: Living both in water and on land exposes them to pollutants in multiple environments, doubling their vulnerability
- Sensitive eggs: Their unprotected, jelly-like eggs are directly exposed to environmental conditions and easily affected by water quality
- Respiratory dependence: Their ability to breathe through their skin means air pollutants can directly affect their respiratory function
- Early life vulnerability: Their aquatic larvae (tadpoles) are especially sensitive to water quality changes during critical developmental stages
how are reptiles unique
Reptiles are distinguished from Amphibians and mammals based on being Amniotes with scales, they are air breathing vertebrates that have internal fertilization and a scaly body.
Birds are considered reptiles as they have scales, lay amniotic eggs, and are descended from reptiles (dinosaurs)
what are 6 features which help distinguish mammals from other animals
- Hair/fur: All mammals have hair or fur at some point in their lives, which helps with insulation and sensation
- Mammary glands: Female mammals produce milk to nourish their young
- Complex brain: Relatively large brain with a well-developed cerebral cortex
- Middle ear bones: Three distinct middle ear bones (malleus, incus, stapes) for enhanced hearing
- Specialized teeth: Different types of teeth (heterodont dentition) adapted for various feeding strategies
- Diaphragm: A muscular structure that aids in breathing
what are the three main groups of mammals
There are three main groups of mammals
Monotremes includes platypus, and Echidnas
Marsupials includes kangaroos, Thylacines, koalas, etc
Eutherians include us, whales, elk, etc
