UNIT 8: MARINE REPTILES, BIRDS, MAMMALS

• Desiccation is the process of drying out or losing moisture, which marine animals must counteract.
• Ectothermic organisms rely on external conditions to regulate body temperature.
• Salt glands help marine birds and reptiles excrete excess salt.
• Osmolarity refers to the concentration of solutes in a solution and is critical for water balance.
• Carapace is the upper shell of a turtle.
• Plastron is the underside shell of a turtle.
• Scutes are bony plates or scales on reptiles like turtles and crocodiles.
• Basking is when reptiles rest in the sun to regulate body temperature.
• Endothermic organisms generate their own body heat internally.
• Tortoise shell jewelry is made from tortoise shells, often illegally.
• Uropygial gland produces oil for birds to waterproof feathers.
• Preening is when birds groom and maintain feathers.
• Nictitating membrane is a third eyelid for eye protection in birds and some reptiles.
• Gular sac is a throat pouch in birds like pelicans, used for food storage.
• Tactile organs are sensory structures that detect environmental changes in marine mammals.
• Sexual dimorphism refers to appearance differences between males and females of a species.
• Diaphragm is a muscle aiding respiration in mammals.
• Sebaceous glands in mammals secrete oils for lubrication.
• Blubber is a thick fat layer in marine mammals for insulation and energy storage.
• Pinnae are external ear parts, present in sea lions but not seals.
• Tetrapod is a four-limbed vertebrate.
• Heterodont dentition is having different types of teeth.
• Polygamous describes a mating system where one individual mates with multiple partners.
• Harem is a social structure with one male mating with multiple females.
• Vibrissae are whiskers on marine mammals that detect movement in water.
• Baleen are filter-feeding structures in whales.
• Keratin is a protein in baleen, feathers, and scales.
• Throat grooves are folds in baleen whales that expand during feeding.
• Homodont dentition is having teeth of the same shape and size.
• Melon is a fatty structure in toothed whales used for echolocation.
• Echolocation is using sound waves to detect objects.
• SONAR is a human technology that mimics echolocation.
• Hemoglobin is a protein in blood that carries oxygen.
• Myoglobin is a protein in muscles that stores oxygen.
• Basal Metabolic Rate (BMR) is the energy an organism uses at rest.
• Vasoconstriction is the narrowing of blood vessels reduce heat loss and conserve oxygen.
• Nitrogen narcosis is a condition affecting deep-diving mammals due to nitrogen buildup.

Characteristics of Reptiles, Birds, and Mammals

• Reptiles are ectothermic with scaly skin, lay eggs on land, and breathe with lungs.
• Birds are endothermic with feathers and hollow bones, lay hard-shelled eggs, and have a beak.
• Mammals are endothermic with fur or hair, produce milk, and give birth to live young (except monotremes).

Identifying Organisms

• Reptiles include sea turtles, marine iguanas, and sea snakes.
• Birds include penguins, albatrosses, and frigate birds.
• Mammals include dolphins, whales, seals, and sea otters.

Contrasting Examples

• Turtles are reptiles with scaly skin and ectothermy, while penguins are birds with feathers and endothermy.
• Seals lack external ear flaps and move awkwardly on land.
• Sea lions have external ear flaps and use flippers to walk.

Ectothermy vs. Endothermy

• Ectothermy involves body temperature depending on the external environment.
• Endothermy involves body temperature being regulated internally through metabolism.
• Endotherms are active in cold environments, while ectotherms require external heat.

Turtle Reproduction

• Turtles lay eggs on sandy beaches.
• Females return to the same nesting site every few years.
• Hatchlings emerge at night and move toward the ocean.

Evolution

• Fish evolved into amphibians, then reptiles.
• Reptiles split, leading to mammals and birds.
• Birds evolved from theropod dinosaurs.
• Mammals evolved from synapsid reptiles.

Bird Adaptations

• Salt glands remove excess salt.
• Webbed feet aid in swimming.
• Hollow bones reduce weight for flight.
• Waterproof feathers maintain buoyancy and warmth.

Marine Mammal Characteristics

• Blubber provides insulation and energy storage.
• Mammary glands provide milk to young.
• Streamlined bodies reduce drag in water.
• Echolocation is used to locate prey.

Sexual Dimorphism

• Sexual dimorphism is physical differences between males and females.
• Male elephant seals are much larger than females.

Mammalian Skin Glands

• Sebaceous glands secrete oil for waterproofing and skin protection.
• Sweat glands regulate temperature (absent in marine mammals).

Diving Adaptations

• Vasoconstriction reduces blood flow to non-essential organs.
• Myoglobin & Hemoglobin store oxygen for dives.
• Slowed heart rate (bradycardia) conserves oxygen.

Population Techniques

• Aerial surveys involve counting from aircraft.
• Tagging & tracking uses GPS and radio tags.
• Acoustic monitoring involves listening to vocalizations.

Advantages of Blubber

• Blubber provides insulation.
• Blubber provides buoyancy
• Blubber provides energy storage.

Similarities

• Dolphins and penguins both have streamlined bodies to reduce water resistance.
• Dolphins and penguins both exhibit social behaviors.
• Penguins use flippers, dolphins use fins for swimming adaptations.

Conservation

• The Marine Mammal Protection Act (1972) prevents marine mammal hunting.
• Conservation efforts have helped recover sea otter, whale, and seal populations.
• Climate change, pollution, and fishing nets still pose challenges.

Marine Reptiles Characteristics

• Dry, scaly skin prevents water loss.
• They produce eggs (oviparous) with soft, leathery shells to prevent desiccation.
• Reptiles are ectothermic, using external sources to regulate body temperature.
• Reptiles bask in the sun to regulate body temperature
• Salt glands help maintain osmolarity by removing excess salt.

Sea turtle characteristics

• Bodies are enclosed in two shells: carapace (dorsal) and plastron (ventral).
• Vertebrae and ribs are fused to the inside of the carapace.
• Limbs are modified into flippers for swimming.
• They bask at the surface to increase body temperature.
• Lay 100-160 eggs in the sand and return to land, usually their birth beach, to lay eggs.
• The incubation period is approximately 60 days.

Marine Iguanas Characteristics

• Marine Iguanas have one species which is the Galapagos marine iguana.
• Their tail is laterally flattened for swimming.
• They remain close to shore and can dive up to 10 meters for food.
• They are herbivorous, grazing on algae.
• They bask on rocks to regulate body temperature.
• Marine Iguanas sneeze out excess salts, leaving a crusty residue on their heads.

Saltwater Crocodiles

• The tail is laterally flattened and used for swimming.
• They can travel up to 100 miles from shore.
• Basking on land is used to regulate temperature.
• Saltwater crocodiles can be 5 meters in length.
• Saltwater crocodiles are aggressive carnivores inhabiting estuarine communities.

Marine Bird Characteristics

• Birds are endothermic, regulating body temperature internally.
• Flight is a common characteristic, enabling long-distance travel for resources.
• Birds have hollow bones to reduce weight.
• Eggs are hard-shelled (oviparous).
• Salt glands eliminate excess salts.
• Webbed feet or partially webbed feet.
• Waterproof feathers ensure birds are not weighed down.
• An uropygial gland produces oil for waterproofing.
• Birds have nictitating membranes, for eye protection during dives.

Marine Mammal Characteristics

• Most have hair for insulation, protection, camouflage, communication, sensory input, buoyancy, and sexual dimorphism
• Marine Mammals are Endothermic.
• They have mammary glands used to nourish young.
• Except for monotremes, marine mammals are Viviparous (give live birth).
• Muscular diaphragm aids breathing.
• They have un-nucleated red blood cells to carry more oxygen.
• Marine Mammals have a four-chambered heart to support an active lifestyle.
• Sebaceous glands produce sebum for waterproofing.
• Sweat glands help detoxify the body.
• They have separate urogenital openings (except monotremes).
• Most have pinnae (external ear flaps) for focusing sound.
• Marine mammals usually have seven cervical vertebrae (except manatees).
• Inner ear bones allow for efficient sound transmission.

Diving Adaptations

• Marine mammals exhibit efficient surface breathing, replacing up to 90% of air in lungs with each breath.
• Increased hemoglobin and myoglobin improve oxygen storage.
• A decreased basal metabolic rate (BMR) reduces energy consumption.
• Selective vasoconstriction restricts blood flow to conserve oxygen.
• Collapsible lungs help avoid nitrogen absorption.
• Marine mammals exhibit high resistance to carbon dioxide.