Download Marine Taxonomy / Zoology Lecture

TAXONOMY
EVERY BIOLOGIST, REGARDLESS OF HIS AREA OF INTEREST, MUST LEARN THE FUNDAMENTALS OF
CLASSIFICATION.
INDEED, THE FIRST STEP IN ANY STUDY IS THE CORRECT IDENTIFICATION OF THE ORGANISMS BEING
STUDIED, AND THIS IS A MATTER OF TAXONOMIC PROCEDURE.
TAXONOMY IS THE SCIENCE OF CLASSIFICATION, WHICH PROVIDES A LOGICAL INTERNATIONAL
SYSTEM FOR THE NAMING OF ORGANISMS.
OUR SYSTEM OF CLASSIFICATION, KNOWN AS THE BINOMIAL SYSTEM (TWO NAMES), WAS
ORIGINATED BY A SWEDISH BIOLOGIST NAMED LINNAEUS.
EACH ORGANISM IS GIVEN A SCIENTIFIC NAME CONSISTING OF TWO LATIN WORDS.
THE FIRST WORD OF THE SCIENTIFIC NAME, ALWAYS WRITTEN WITH A CAPITAL, IS THE
GENERIC NAME, THAT IS, THE NAME OF THE GENUS IN WHICH THE ORGANISM IS PLACED.
THE SECOND WORD IS THE SPECIFIC NAME, WHICH IS NOT CAPITALIZED, AND
IS THE SPECIES OF THE ORGANISM.
THUS THE MALLARD DUCK, WHICH OCCURS ALMOST THROUGHOUT THE WORLD, MAY BE KNOWN BY
MANY COMMON NAMES IN VARIOUS COUNTRIES, BUT ITS SCIENTIFIC NAME,
Anas platyrhynchos, IS THE SAME EVERYWHERE.
EACH SPECIES BELONGS TO A SERIES OF HIGHER CATEGORIES, ALSO ORIGINATED BY LINNAEUS.
THIS HIERARCHICAL CLASSIFICATION INCLUDES, FROM GREATEST TO SMALLEST, THE FOLLOWING
CATEGORIES:
How to remember them
KINGDOM
King
PHYLUM
Phillip
CLASS
Came
ORDER
Over
FAMILY
For
GENUS
Good
SPECIES
Soup
THERE ARE FIVE RECOGNIZED KINGDOMS IN THE CLASSIFICATION SYSTEM. THEY ARE:
PROTISTA - THE PROTIST KINGDOM INCLUDES THE PROTOZOANS (FIRST LIFE).
MANY PROTISTS ARE UNICELLULAR MICROSCOPIC ORGANISMS. PROTISTS ARE EUKARYOTES, OR
ORGANISMS WITH A TRUE NUCLEUS.
MONERA - THE MONERAN KINGDOM INCLUDES ALL BACTERIA AND THE BLUE-GREEN ALGAE.
MONERANS ARE UNICELLULAR PROKARYOTES, OR ORGANISMS WITHOUT A TRUE
NUCLEUS.
PLANTAE - MOST PLANTS ARE MULTICELLULAR ORGANISMS WITH SPECIALIZED TISSUES AND
ORGANS.
PLANTS ARE AUTOTROPHIC, THAT IS THEY MAKE THEIR OWN FOOD FROM SIMPLE
SUBSTANCES, AND CONTAIN CHLOROPHYLL. PLANT CELLS HAVE CELL WALLS.
FUNGI - MOST FUNGI ARE MULTICELLULAR ORGANISMS THAT HAVE SIMPLE STRUCTURES. ALL
FUNGI ARE EUKARYOTES, AND HETEROTROPHIC. THIS KINGDOM INCLUDES MUSHROOMS,
MOLDS, AND YEAST.
ANIMALIA - THE ANIMAL KINGDOM IS MADE UP OF ONLY MULTICELLULAR ORGANISMS.
ANIMALS ARE HETEROTROPHS.
THESE ORGANISMS ARE THE MOST COMPLEX, HAVE TISSUES, AND MOST HAVE ORGANS
AND ORGAN SYSTEMS. ANIMAL CELLS DO NOT HAVE CELL WALLS OR CHLOROPHYLL.
EXAMPLES:
HUMAN
ASPEN
KINGDOM
ANIMALIA
PLANTAE
PHYLUM
CHORDATA
TRACHEOPHYTA
CLASS
MAMMALIA
ANGIOSPERMAE
ORDER
PRIMATES
APETALAE
FAMILY
HOMINIDAE
SALICACEAE
GENUS
Homo
Populus
SPECIES
sapiens
tremuloides
What is diversity of life?
Variety is the spice of life! Diversity is simply the wide variety of organisms in our world. Species diversity is a measure that
combines the number, or richness, of species and their distribution on land and in the sea.
Diversity is the key!
Diversity is the key that unlocks the success of organisms in our world. There are a variety of habitats in our world such as
mountains, valleys, deserts, and oceans. Animals and plants that thrive in various habitats each play a unique role.
For example, a killer whale plays the role of a top predator in our oceans because of its adaptations for survival, such as its
size, powerful swimming, and coloration. To take this animal and place it into another environment such as a tropical rain
forest would be absurd; it would not survive. Animals and plants take many forms, inhabitating every environment in our
world. Diversity is the key that unlocks the success of organisms in our world. Animals and plants take many forms,
inhabitating every environment, from forests on land to forests in the sea.
A species is a special group.
A species is a group of plants or animals that are genetically similar and so are able to reproduce with each other. A
population is a group of plants or animals of the same species that live in the same area and have the opportunity to breed
with each other. For example, there is a population of killer whales in Pacific Northwest waters and a separate population in
the Antarctic. Although the animals are the same species, they are geographically isolated and therefore do not commonly
breed with each other.
Whicn ones will survive?
Natural selection refers to proecesses that result in the survival and reproduction of individuals best suited for the
environment in which they live. All species tend to produce more offspring than the environment can sustain. Not all
individuals can survive. Some fish lay millions of eggs, only a few of which will live to be adult fish and reproduce. But
which ones will survive?
Variety is the basis for natural selection.
Individuals within a population are not all exactly the same. Genetically, they vary. Individuals with favorable variations tend
to survive, and those with less favorable variations die. Survivors reproduce others with favorable traits.
A gene pool contains all the traits or genes in any one population that can be passed on through generations. The gene pool
may change slightly over long periods of time as traits change for better survival in specific habitats, but the pool is mainly
consistent to ensure the success of the population.
Plants and animals with biological characteristics better suited for their environment are better represented in future
generations. So through successive generations, gradual and continuous changes occur in the population. Eventually these
changes result in new adaptations and species.
That's a lot of species.
About 1.4 million species of plants and animals have been identified. Some scientists estimate that there may be as many as
100 million species! How do we keep track of them all? More than 2,000 years ago Aristotle, a Greek philosopher, devised
the first classification system with two kingdoms and simple categories to name plants and animals. In the eighteenth centruy,
a Swedish botanist, Carolus Linnaeus, created a classification system based on similarities and differences among
organisms that separate them into categories. The sequence of categories is as follows: kingdom, phylum, class, order,
family, genus, species.
Linnaeus prepared the scientific names of each organism in Latin. Even today, we use Latin or Greek to describe organisms
so that taxonomists world-wide can communicate. Linnaeus used two words to name each organism, a genus name and a
species name. In his system, called binomial nomenclature or two-word naming, the genus describes the group to which the
organism belongs, and the species describes the specific animal.
Species vary in a world abounding with an array of life forms. Imagine a world filled with just one
species. Diversification ensures a species-rich world.
Organisms have been divided into a five-kingdom classification system.
As scientists discovered new organisms and changed their ideas about what characteristics are important in classifying
organisms, the classification system changed. Today's classification system contains five kingdoms: Monera (prokaryotes),
Protista (single-celled eukaryotes), Fungi (molds and yeasts), Planate (plants), and Animalia (animals). This five-kingdom
classification system was suggested by R.H. Whittaker in 1969. Linnaeus used a genus name and a species name to describe
each organism. The scientific name for the West Indian manatee is Trichechus manatus.
Kingdom Animalia
Members of the animal kingdom share these basic characteristics:
 mulitcellular (bodies made up of more than one cell)
 eukaryotic (each cell contains a nucleus and membrane-enclosed organelles)
 cell membranes without cell walls
 heterotrophs (do not make their own food but consume other organisms)
The following phyla include some of the most common animals.
Key Animal Phyla of the Oceans
Phylum: Porifera
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characteristics: aquatic, asymmetrical animals lacking distinct tissues and organs; sessile body consists of two
layers supported by a stiff skeleton; reproduce sexually or asexually.
example: sponges
Phylum: Cnidaria (formerly Coelenterata)
characteristics: radial symmetry, central mouth surrounded by tentacles, nematocysts; reproduces sexually
or asexually. Corals are members of the phylum Cnidaria.
examples: corals, sea anemones, jellyfishes, hydras
 Class Hydrozoa--Portuguese man-of-war
 Class Scyphozoa--Jellyfish
 Class Anthozoa--Corals and sea anemones
Phylum: Platyhelminthes
characteristics: three cell layers; digestive cavity having one opening; no circulatory or respiratory
systems; reproduce sexually or asexually.
examples: flatworms (tapeworms, flukes, planarians)
Phylum Nematoda
characteristics: mostly parasitic; tubular body, bilateral symmetry; digestive tract with two openings;
reproduce sexually
examples: roundworms (ascaris, hookworms)
Phylum: Bryozoa
characteristics: microscopic, aquatic organisms; form branching colonies; feed with ciliated tentacles in
U-shaped row.
examples: moss animals
Phylum Mollusca
characteristics: soft-bodied, true coelom, muscular foot, visceral mass and mantle; most aquatic; many
have shells; reproduce sexually.
examples: clams, octopuses, snails
 Class Polyplacophora--Chitons
 Class Gastropoda--snails and slugs
 Class Bivalvia--clams, mussels, oysters, scallops
 Class Cephalopoda--Squid, octopi, cuttlefish, nautiloids

Phylum Annelida--Segmented worms
characteristics: true coelom; longitudinal and circular muscles; fairly complex circulatory, digestive,
respiratory, and nervous systems; reproduce sexually.
examples: segmented worms (leeches, earthworms)
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Phylum Arthropoda
characteristics: segmented body; paired, jointed appendages; exoskeleton; open circulatory system;
complex nervous system with brain and two ventral nerve cords; reproduce sexually. The spiny lobster
exhibits arthropod characteristics of an exoskeleton and paired, jointed appendages.
examples: horseshoe crabs, lobsters, insects
 Subphylum Crustacea--Crabs, lobsters, shrimp, copepods, ostracods, barnacles
 Subphylum Chelicerata--Horseshoe "crabs" and sea spiders
 Subphylum Uniramia--Insects (nearly all terrestrial)
 Subphylum Trilobita--Trilobites (all extinct)
Phylum Echinodermata
characteristics: radial symmetry; calcium endoskeleton; open circulatory system; complex nervous system
with brain and two ventral nerve cords; reproduce sexually.
examples: sea stars, sea cucumbers, sea urchins
 Class Stelleroidea--Sea stars and brittle stars
 Class Echinoidea--Sea urchins and sand dollars
 Class Holothuroidea--sea cucumbers
 Class Crinoidea--Sea lilies and feather stars
Phylum Chordata
characteristics: has a notochord, throat slits, and tail at some stage of development; reproduces sexually.
People are in the phylum Chordata. But we're not the only ones.
Chordates are divided into the following classes:
Class: Cephalaspidomorphi
characteristics: circular mouth has sucking disc, no jaw, no paired fins, one nostril.
example: lampreys
Class: Myxini
characteristics: circular mouth has barbles, no jaw, no paired fins, one nostril, no eyes.
example: hagfishes
Phylum Chordata continued
Class: Chondrichthyes
characteristics: skeleton made of cartilage, jaws, paried fins, paired nostrils, scales, two-chambered heart.
examples: sharks, skates, rays, chimaeras
Class: Osteichthyes
characteristics: skeleton made of bone, jaws, fins, most with scales, two-chambered heart.
example: bony fishes
Class: Amphibia
characteristics: begin life in the water, gills replaced by lungs in the adult form, lay eggs, three-chambered
heart.
examples: frogs, toads, salamanders
Class: Reptilia
characteristics: thick, scaly or platelike skin; ectothermic (cold-blooded); embryo develops in the shell
(young born live or hatch from egg); four-chambered heart.
examples: snakes, lizards, turtles, crocodiles
Class: Aves
characteristics: outer covering of feathers, endothermic (warm-blooded), have front limbs modified as wings,
lay eggs, four-chambered heart.
examples: all birds including penguins, flamingos, eagles, parrots, and ducks
Class: Mammalia
characteristics: breathe air, have hair at some stage of development, give live birth, mammary glands,
examples: humans, whales, horses, bears
What is diversity of life?
Variety is the spice of life! Diversity is simply the wide variety of organisms in our world. Species diversity is a measure that
combines the number, or richness, of species and their distribution on land and in the sea.
Diversity is the key!
Diversity is the key that unlocks the success of organisms in our world. There are a variety of habitats in our world such as
mountains, valleys, deserts, and oceans. Animals and plants that thrive in various habitats each play a unique role.
For example, a killer whale plays the role of a top predator in our oceans because of its adaptations for survival, such as its
size, powerful swimming, and coloration. To take this animal and place it into another environment such as a tropical rain
forest would be absurd; it would not survive. Animals and plants take many forms, inhabitating every environment in our
world. Diversity is the key that unlocks the success of organisms in our world. Animals and plants take many forms,
inhabitating every environment, from forests on land to forests in the sea.
A species is a special group.
A species is a group of plants or animals that are genetically similar and so are able to reproduce with each other. A
population is a group of plants or animals of the same species that live in the same area and have the opportunity to breed
with each other. For example, there is a population of killer whales in Pacific Northwest waters and a separate population in
the Antarctic. Although the animals are the same species, they are geographically isolated and therefore do not commonly
breed with each other.
Whicn ones will survive?
Natural selection refers to proecesses that result in the survival and reproduction of individuals best suited for the
environment in which they live. All species tend to produce more offspring than the environment can sustain. Not all
individuals can survive. Some fish lay millions of eggs, only a few of which will live to be adult fish and reproduce. But
which ones will survive?
Variety is the basis for natural selection.
Individuals within a population are not all exactly the same. Genetically, they vary. Individuals with favorable variations tend
to survive, and those with less favorable variations die. Survivors reproduce others with favorable traits.
A gene pool contains all the traits or genes in any one population that can be passed on through generations. The gene pool
may change slightly over long periods of time as traits change for better survival in specific habitats, but the pool is mainly
consistent to ensure the success of the population.
Plants and animals with biological characteristics better suited for their environment are better represented in future
generations. So through successive generations, gradual and continuous changes occur in the population. Eventually these
changes result in new adaptations and species.
That's a lot of species.
About 1.4 million species of plants and animals have been identified. Some scientists estimate that there may be as many as
100 million species! How do we keep track of them all? More than 2,000 years ago Aristotle, a Greek philosopher, devised
the first classification system with two kingdoms and simple categories to name plants and animals. In the eighteenth centruy,
a Swedish botanist, Carolus Linnaeus, created a classification system based on similarities and differences among organisms
that separate them into categories. The sequence of categories is as follows: kingdom, phylum, class, order, family, genus,
species.
Linnaeus prepared the scientific names of each organism in Latin. Even today, we use Latin or Greek to describe organisms
so that taxonomists world-wide can communicate. Linnaeus used two words to name each organism, a genus name and a
species name. In his system, called binomial nomenclature or two-word naming, the genus describes the group to which the
organism belongs, and the species describes the specific animal.
Species vary in a world abounding with an array of life forms. Imagine a world filled with just one species. Diversification
ensures a species-rich world.
Marine Life throughout Earth History
Proterozoic fauna
Stromatolites (cyanobacteria or blue-green algae) formed reefs.
Acritarchs are cysts of dinoflagellates or green algae.
Ediacaran-Vendian fauna (latest Proterozoic)
Radiation of soft pancake- and ribbon-shaped creatures. Some workers consider them to be primitive "jellyfish" and
"worms," while others believe they are an early radiation of multicellular animals that were thin but had no internal
complexity.
Tommotian (small shelly) fauna (earliest Cambrian)
Tiny cups, caps, and other hard fossils. They probably include primitive sponges and gastropods (snails).
Cambrian fauna
Trilobites (many-legged arthropods, now extinct)
Inarticulate brachiopods (the two shells come apart after death)
Primitive mollusks (look like slugs with pointed hats on)
Nautiloids (ancestors of the living chambered nautilus)
Weird echinoderms (distantly related to starfish and sea urchins)
Archaeocyathids (cone-shaped; the reef builders of the Cambrian)
Bizarre soft-bodied Burgess Shale animals such as Opabinia (five eyes and a nozzle), Wiwaxia (sclerites), Hallucigenia
(spike legs and seven ?mouths), and Anomalocaris (big carnivore)
Paleozoic fauna (Ordovician to Permian)
Articulate brachiopods (the two shells stay attached after death)
Graptolites (planktonic animals found in black shales)
Conodonts (tiny teeth and plates of an illusive creature)
Ostracods (small ball-shaped crustaceans)
Rugose and tabulate corals (the primary reef builders)
Bryozoans (twig-like animals that helped make reefs)
Crinoids (stalked echinoderms like modern sea lilies)
Fusilinids (wheat-grain-shaped protists with a hard shell)
Ammonoids with simple sutures (arose from nautiloids)
Eurypterids (giant carnivorous arthropods)
Fishes (jawless, lobe-finned, ray-finned, and shark types)
Mesozoic fauna (Triassic to Cretaceous)
Ammonoids with complex sutures
Oysters and other bivalve mollusks; gastropod mollusks
Rudist bivalves (looked like corals and built reefs)
Hexacorals (primary reef builders)
Echinoids (sea urchins and sand dollars)
Planktonic foraminifera (protists with a hard shell)
Teleost fishes (advanced ray-finned fishes)
Marine reptiles: ichthyosaurs, plesiosaurs, mosasaurs, crocodiles (some giant), phytosaurs, sea turtles (some giant)
Cenozoic fauna (Tertiary and Quaternary)
Invertebrate and fish life similar to the Cretaceous
Marine mammals: whales, dolphins, porpoises, seals, manatee