Biology of Fishes Final Exam

Systematics

the study of the relationship among species/lineages

Classification

defining and naming groups of organisms

Character

heritable feature possessed by an organism

Synapomorphy

a shared, derived trait

Clade

a group of organisms that includes the most recent common ancestor of all its members and all descendants of that common ancestor

Clagogenesis

the development of a new clade

Anagenesis

a species changing over time

Convergence

similarities that arose independently in two or more organisms that are not closely related

Derived

describes a character state that is present in one or more subclades, of a clade under consideration

Taxonomy

defining and naming species (generally)

Monophyletic

all members of a named group (no others) are derived from a common ancestor

Paraphyletic

all members of a named group (and others) are derived from a common ancestor

Polyphyletic

members of a named group are not derived from an immediate common ancestor

Homology

a trait that has been inherited from a common ancestor that also possessed the trait

Lineage

any group of organisms connected by a continuous line of descent

Outgroup

a group of organisms outside the clade of interest, generally chosen because they lack characters important to the clade of interest OR chosen because they share characters with the clade of interest

Primitive

describes a character that is present in the common ancestor of a clade

Sister group

the two clades resulting from the splitting of a single lineage

Taxa

a broadly used term that can apply to any focal group

Adaptation

a feature, which may or not be conspicuous, that has a very specific function that acts to specialize the organism

Specialist

an organism/species that performs best in very specific situations

Generalist

a relatively unspecialized organism

Species richness

Higher near the equator, Stable conditions, More food availability, More space

Speciation rate

Higher near poles, Unstable conditions, Fewer species

Competitive exclusion principle

species can be competitively excluded from a niche by dominant/abundant incumbent species

Marine fishes

Concentrated near coral reefs, Lots of food, shelter from predators

Freshwater fishes

Loosely concentrated near the equator, Mainly on large landmasses with large, warm river systems

Rays

Rays are live-bearing.

Skates

Skates lay eggs and have prominent dorsal fin.

Rays vs Skates

Rays have absent or reduced dorsal fin, are kite-shaped, while skates have fleshy tails and lack spines.

Selachii

Selachii refers to sharks.

Skeletal anatomy of sharks

Includes 5-gill arches, pectoral girdle, pectoral fins, first dorsal fin, vertebrae, second dorsal fin, pelvic fins, anal fin, caudal fin.

Buoyancy in sharks

Achieved through a large, oil-filled liver and a heterocercal fin where most of the tail is above the midline.

Gill openings in sharks

Are independent and physically separate but are connected to the esophagus.

Modes of respiration in sharks

Include actively pumping water across gills with mouth movements, using spiracle to pull water in, and ram ventilation.

Placoid scales

Type of scale found in sharks.

Teeth in sharks

Made of calcium phosphate and can be smooth or serrated.

Ampullae of Lorenzini

Electroreceptors that detect electric fields.

Cartilaginous skeleton

Skeleton type found in sharks.

Chondrocranium

The skull of sharks that lacks sutures.

Soft fin rays

Unsegmented in sharks.

Teeth attachment in sharks

Teeth are not fused to the jaw.

Claspers

Structures that males have for reproduction.

Dipnoi

Lungfishes found on 3 different continents due to the breakup of the Gondwana landmass.

Aestivation

A period of dormancy when the water dries up; lungfishes can survive up to 5 years.

Bony skeleton

Type of skeleton found in lungfishes.

Actinistia

Coelacanths that have a vestigial lung derived from the swim bladder.

Polypteriformes

Reedfishes that respire using lungs and can make short over-land excursions.

Acipenseriformes

Includes sturgeons and paddlefishes; sturgeons lack scales and have bony plates.

Amiiformes

Bowfins with a vascularized swim bladder.

Lepisosteiformes

Gars with a vascularized swim bladder that functions as a lung.

Elopiformes

Tarpon that are obligate air breathers.

Anguilliformes

True eels with different scale types in freshwater and marine environments.

Osteoglossiformes

Includes arapaima, arowana, and elephant fish with bony tongues.

Ostariophysi

Includes carps, catfish, tetras, and knife fish with a Weberian apparatus.

Fish swimming modes

Include body-caudal fin (BCF) swimming and median-paired fin (MPF) swimming.

Body-caudal fin (BCF) swimming

Includes various swimming types such as anguilliform, carangiform, and thunniform.

Caudal fin types

Include protocercal, heterocercal, hypocercal, homocercal, and hemihomocercal.

First jaws in fish

Occurred in placoderms with jaws made of bony plates.

Aquatic environment

More viscous, requiring more force and motion for prey capture.

Gill-based respiratory system

Necessitates well-developed gill arches in aquatic environments.

Fish limbs

Less dexterous due to the absence of hands and digits; functional demands for prey capture lie with jaws and branchial system.

Terrestrial organisms

Less reliant on jaws for feeding compared to aquatic organisms.

Terrestrial environment

More beneficial to invest in areas like hearing rather than jaw development.

Pectoral fins

Responsible for most fine-scale maneuvering in fish.

Pectoral girdle

Consists of the cleithrum, scapula, and coracoid bones.

Muscle attachment

Muscles attach from cleithrum and coracoid to the radials of the pectoral fin.

Lever systems

Mechanical systems that include Type 1, Type 2, and Type 3 configurations.

Type 1 lever

F between L and force; provides a middle ground.

Type 2 lever

L between F and force; primarily designed for strength.

Type 3 lever

Force between F and L; produces large and fast movements with little effort.

Jaw length

Negatively correlated with bite force in mammals.

Herbivores and carnivores

Have short jaws that produce a forceful bite.

Insectivores

Have long jaws that produce a fast bite.

Jaw length/shape

Correlated with bite force in mammals/birds.

Form-function relationships

When anatomy predictably manifests as a function.

Functional morphology

Characterizes the relative size and shape of the jaws.

Crevice feeders

Have big jaws, upper longer than lower.

Molluscivores

Have intermediate jaws, both the same length.

Browsers

Have compact jaws, slightly downturned.

Coral reefs

Provide a complex benthic environment, making biting a viable feeding strategy.

Fish feeding strategies

Expanded rapidly following the formation of modern reefs.

Fish jaw biomechanics

Biting and suction feeding modes nearly comprehensively differ in their biomechanics.

Bony plates

Effective against teeth, less effective if predator can eat them whole.

Spines

Always arranged along the top and bottom of the body, increases body depth; often utilized as a delivery system for venom.

Stonefishes

The most venomous fishes in the world, produce verrucotoxin.

Tetrodotoxin

Produced by pufferfish, attacks the nervous system and causes paralysis.

Mimicry

************* something else that's dangerous, requires predator avoidance.

Pseudomimicry

Anatomy mimics another anatomical feature, misdirecting attention away from vital organs.

Crypsis

Color pattern blends into surrounding environments to avoid predator attention.

Large body size

Predators cannot eat them, too much risk/hassle to attack.

Sociality

Part of a large group; prey can detect predators faster and take shelter amongst numbers.

Fleeing

Physically outswim predators or retreat to areas inaccessible to predators.

Electric shock

Electric fields mainly for search for prey; electric eels produce a strong electric current.

Life history

Pattern of allocation of resources to maintenance, growth, and reproduction throughout an organism's lifetime.

Guppies

Distributed in ponds throughout Trinidad, co-occur with rivulus in low predation and crenicichla in high predation.

Guppy coloration

Fewer, smaller spots in high predation areas to reduce visual detection by predators.

Salmon lifecycle

Eggs hatch in freshwater after 3 months, followed by stages from alevin to adult.

Olfaction

Smell becomes imprinted when they are smolts before migrating to sea.

Magnetoreception

Have a domain magnetite in their skull.