Lab 8 Flashcards

Question

compare the habitats of hagfish vs lampreys

Answer 1

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.

Answer 2

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.

Answer 3

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

Answer 4

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.

Answer 5

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.

Answer 6

Fish can be classified as aquatic, anamniotic, gill-bearing vertebrate animals with swimming fins, and a hard skull, but lacking limbs with digits.

Answer 7

Chondrichthyes have two subclasses: Elasmobranchii includes sharks, rays, skates, and sawfish Holocephali includes the chimaeras

Answer 8

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.

Answer 9

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.

Answer 10

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.

Answer 11

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

Answer 12

- 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

Answer 13

- **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.

Answer 14

- **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

Answer 15

- **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

Answer 16

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)

Answer 17

- **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

Answer 18

There are three main groups of mammals Monotremes includes platypus, and Echidnas Marsupials includes kangaroos, Thylacines, koalas, etc Eutherians include us, whales, elk, etc