Marine Biology: Larval Dispersal, Fish, Marine Reptiles, Birds, and Mammals

Vocabulary flashcards covering marine larvae, fish morphology and classification, marine reptiles, seabirds, and marine mammals.

Larva

The immature form of an organism before undergoing metamorphosis.

Leichtotrophic Larva

Non-feeding marine larvae that rely on yolk rather than eating plankton, characterized by a low dispersal range typical of brooding organisms.

Planktotrophic Larva

Feeding marine larvae that eat plankton, develop early feeding structures from energy-poor eggs, and have a large dispersal range typical of broadcasting organisms.

Direct Development

A developmental mode where organisms are born looking exactly like the adult form only smaller, completely bypassing a larval stage.

Connectivity

The interchange of individuals between populations that contribute to the genetic pool.

Dispersal

The process by which organisms leave their birth site and travel to different locations.

Life Cycle

The sequence of changes an organism undergoes through life, taking different forms and eventually returning to the starting state.

Oviparous

A reproductive pattern where eggs are laid externally and rely on yolk for nourishment, involving either external or internal fertilization.

Viviparous

A reproductive pattern where the embryo grows internally via internal fertilization only, with juveniles bypassing a larval stage.

Ovoviviparous

A reproductive pattern where eggs depend on yolk and are incubated internally until live birth.

Recruitment

The incorporation and introduction of members of a species into a population after completing their larval stage and dispersing.

Gene Flow

The transfer of genetic material from one location or population to another.

Speciation

The evolutionary process occurring when organisms split into two reproductively isolated groups that preclude gene flow from a common ancestor, often caused by a lack of connectivity.

Biological Species Concept (BSC)

The concept defining species as groups of interbreeding natural populations that are reproductively isolated from other groups.

Hagfishes

Jawless, deep-water benthic scavengers lacking vertebrae that feed using dental plates and possess slime glands for protection.

Lampreys

Jawless fish that parasitize bony fish using a sucker-like mouth equipped with a rasping tongue and denticles, returning to freshwater to spawn.

Holocephalans (Chimaeras)

Deep-water cartilaginous fish characterized by an upper jaw attached to the braincase, operculum-covered gills, flat crushing jaw plates instead of teeth, and additional claspers on their heads.

Elasmobranchs

A diverse group of cartilaginous fish comprising over $500$ shark species, rays, and skates that feature placoid scales, an inferior mouth, a heterocercal tail, and a spiral intestine.

Heterocercal Fin

A caudal fin morphology where one side of the posterior fin is noticeably longer than the other side.

Diphycercal Fin

A caudal fin morphology where both sides taper to meet at a sharp point at the end of the posterior fin.

Homocercal Fin

A caudal fin morphology where both sides of the posterior fin are symmetrical in length, producing a fan-like shape.

Cycloid Scales

Fish scales that are thin, circular, and smooth.

Ctenoid Scales

Fish scales that are thin, overlapping, and feature a comb-like edge.

Ganoid Scales

Fish scales that are thick, rigid, diamond-shaped, and hard.

Placoid Scales

Tough, tooth-like scales covering the skin of cartilaginous fishes.

Mechanosensory Lateral Line System

A sensory organ system in fishes that senses vibrations and mechanical stimuli in the water to locate prey, evade predators, school, and find mates.

Fusiform Body Shape

A streamlined body shape adapted for fast and efficient swimming.

Dorso-ventrally Compressed

A disk-shaped body morphology characteristic of benthic organisms that provides high maneuverability.

Amnion

The innermost membrane enclosing the embryo of a mammal, bird, or reptile, enabling reproductive independence from water.

Primary Marine Birds

Birds that live over the open ocean and possess specialized adaptations of their wings and beaks for flight, swimming, and marine feeding.

Secondary Marine Birds

Shorebirds and related species that primarily inhabit estuaries and freshwater environments.

Niche Partitioning

The process by which natural selection drives competing species into different feeding patterns and resource exploitation behaviors.

Marine Mammal

A mammal classified by its ecological role of consuming food derived from the sea.

Mysticetes

A parvorder of cetaceans (baleen whales) possessing between $150$ and $400$ keratin plates suspended from the upper jaw for filter-feeding, exhibiting tooth buds only in the embryonic stage.

Odontocetes

A parvorder of predatory cetaceans characterized by the presence of teeth rather than baleen, including species such as sperm whales.

Population

group of individuals of the same species in a specific area; can breed together

Closed population

separate populations

Stepping stones

Metapopulation; connections among populations

open population

one big population

elasmobranchs

 cartilaginous fish, placoid scales, inferior mouth, heterocercal tail , spiral intestine, internal fertilizers 

Ray finned fishes

bony fish, most numerous and dominant vertebrate in the ocean, has a swim bladder, cycloid or ctenoid scales

The Amniotic egg

requires internal fertilization; independence from water

Sea Snakes

• Limited to the indian and pacific ocean

• Live in shallow water but can dive to 150m 

• 3-4 feet long

• venomous

Sea snake reproduction

• Subfamily 1) oviparous = a few new species

• Subfamily 2) ovoviviparous = live births at sea 

Characteristics of seabirds

 feathers. Hollow bones, strong heart. 

sea turtles migrate

1600km

sea turtles eat

jellyfish, sponges, seaweed and seagrasses

sea turtle maturation

- 30 years; breed every 2-3 years, probably to allow for buildup of fat reserves

sea turtle reproduction

environmental sex determination, lay 100 eggs at a time, 2 month gestation period

monogomy and longevity of seabirds

• Reduced sexual dimorphism

• Late maturity

• Picky males and females in terms of finding partners

mustelids

sea otters

Ursuidae

polar bears

Pinnipeds

seals, sea lions, walruses

Sirenians

• manatees and dugongs

Cetaceans

baleen whales, toothed whales