Mammalian Locomotion & Habitat Adaptation

Flashcards on Mammalian Locomotion and Habitat Adaptation

Cetacea

Mammalian group that reinvaded the sea, first appearing in the Early Eocene (56 to 34 mya).

Sirenia

Mammalian group that reinvaded the sea, first appearing in the Early Eocene.

Pinnepedia

Mammalian group that reinvaded the sea, first appearing in the Late Oligocene (34 to 23 mya).

Puijila darwini

An extinct animal from 24 million years ago, possibly a 'walking seal', suggesting an early stage in the transition of mammals back to aquatic life.

Ambulocetus

An early whale, showcasing the evolutionary adaptation of mammals to aquatic environments.

Prorastomus

An early sea cow, exemplifying the adaptation of mammals to aquatic environments.

Natatorial Mammals

Mammals adapted for swimming; exhibit traits such as reduced surface area to volume ratio, subcutaneous fat/blubber, and counter-current blood flow.

Rete Mirabile

Also known as a plexus, this is a counter-current blood flow system that aids in maintaining endothermy in natatorial mammals.

Fusiform Shape

Streamlined body shape seen in natatorial mammals that minimizes drag in the water.

Blowholes

Modified nostrils on the dorsal surface of cetaceans, allowing them to breathe efficiently at the water's surface.

Nitrogen Narcosis

A condition caused by breathing nitrogen under pressure during deep dives; avoided by cetaceans and deep-diving pinnipeds through lung collapse.

Myoglobin

A protein found in high concentrations in the muscles of aquatic mammals, aiding in oxygen storage for use during dives.

Echolocation

A biological sonar used by cetaceans (and bats) to perceive their surroundings by emitting sounds and analyzing the returning echoes.

Phonic Lips

Structures in whales used for sound production during echolocation; located near the blowhole and nasal sacs.

Spermaceti Organ

A structure in sperm whales used in echolocation.

Baleen

Filtering plates in the mouths of some whales, used to filter small organisms like krill from the water.

Volant Mammals

Mammals capable of flight, primarily bats (Chiroptera).

Chiroptera

The order of mammals comprising bats, characterized by their ability to fly.

Unsteady Aerodynamics

Flight principles used by bats that are more similar to insects than birds, enabling slower flight and more maneuverability.

Microchiropteran

Bats that emit sound with bones in their larynx.

Megachiropteran

Bats that click with their tongues.

PRESTIN gene

A gene involved in convergent evolution, found in outer hair cells of bats and cetaceans; important for sound amplification.

Mechanoreceptor Arrays

Sensory receptors on bat wings that detect airflow and aid in maintaining flight path.

Chiropterophily

Bat pollination of flowers; flowers often have a strong, musky smell at night.

Fossorial Mammals

Mammals adapted for digging and living underground, exhibiting traits such as reduced eyes, robust skeletons, and strong claws.

Hypsodonty

Having high-crowned teeth, an adaptation in herbivores for grazing on abrasive vegetation.

Gigantotherms

Large animals that maintain relatively constant body temperatures due to their low surface area-to-volume ratio.

Graviportal Mammals

Mammals adapted for supporting great weight, with straight, columnar limbs and thick limb bones; typically megaherbivores.

Paenungulata

Also known as Subungulata, this is a group of animals with broad, flat nails that could be viewed as intermediate between claws and hooves, including Proboscidea, Hyracoidea, and Sirenia.