system a tics and taxonomy

8/9/2019 System a Tics and Taxonomy

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Marine Mammals(SPECIFICALLY DUGONG)


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Objectives

To be familiar with the

mechanics of Identiying

organisms to the species level,

particularly dugong


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Rationale

3M species of animals and about 350,000species of plants

There is a need to classify organisms


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SPECIES CONCEPT

Biological Species Concept (BSC)

It defines species in terms of interbreeding

Ernst Mayr"species are groups of

interbreeding natural populations that arereproductively isolated from other such

groups.

The BSC explains why the members of

a species resemble one another, i.e. formphenetic clusters, and differ from other

species.


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Phenetic Traits

A trait/character is any recognizable

character, feature, or property of an

organism.

Evolutionary biologists are interested in acharacter's heritability, so, BSC is compared

to Ecological species concept (ESC).

Richard Dawkins, define a species by the

biological species concept.


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When two organisms breed within a species, their

genes pass into their combined offspring.

As this process is repeated, the genes of different

organisms are constantly shuffled around the

species gene pool. The shared gene pool gives the

species its identity.

By contrast, genes are not (by definition) transferred

to other species, and different species therefore take

on a different appearance.


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Systems of ClassificationA. Artificial System of Classification

based on superficial resemblances

ex. Grouping animals with shells

together

B. Natural Classification

based on evolutionary relationships

started by Karl Von Linne or CarolusLinnaeus

ex. Classification based on

embryonic development


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Seven basic categories or taxa or ranks

Kingdom

Phylum/Division

Class

Order

Family

Genus

Species

Each

taxon/category/r

ank is contained

within the levelabove it


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SPECIE

S

GENUS

FAMILY

ORDER

CLASS

KINGDOM

Smallest unit in classification

A group of related phyla/division

Plylum/DivisionA group of related classes

A group of related species

A group of related genera

A group of related families

A group of related order


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HOMOLOGY (Similarity) is the major basis for classification

Homology in structure/appearanceEx. Orgainsms with jointed appendages are group together

Homology in number of chromosomesEx. Organisms belonging to the same species have the same

number of chromosomes

Homology in functionEx. Animals with backbones have insulin-secreting cells

Homology in chemical compositionEx. Turkeys and turtles differ by 8 amino acids


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Five Kingdom Classification Scheme is

based on the following criteria

Type of cells Number of cells Modes of

Nutrition

Prokaryotic Unicellular Photosynthetic

Eukaryotic Multicellular Absorptive

Ingestive


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MAJORGROUPS OFORGANISMS

Monera

Protista

Fungi

Plantae

Animalia

Bacteria and the blue green algae

Amoeba and Paramecium

Yeasts, molds, mushrooms

Thallophyta

Eukaryotic, multicellular, ingestive type of

Nutrition, primarily motile

Eukaryotic,multicellular, photosynthetic,

primarily non-motile

Embryophyta


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Survey of the Major Groups of Organisms

Kingdom Characteristics Examples

Monera Prokaryotic , Unicellular, some members maygroup to form colony or a filament

Some absorptive, some photosynthetic

Bacteria, BGA

Protista Eukaryotic , unicellular, with some colonial

forms

Some absorptive, some ingestivesome photosynthetic

Paramecium,

Amoeba

Fungi Eukaryotic, multicellular

Absorptive type of nutrition (lack chlorophyll)

Reproduce through spores; non-motile

Yeasts, molds,

mushroom

Plantae Eukaryotic, Multicellular, Photosynthetic

Primarily non-motile

Algae,mosses

Vascular plants

Animalia Eukaryotic, Multicellular, ingestive type of

nutrition, primarily motile

Sponges, fishes,

frogs


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Plants maybe classified as follows:

A. Thallophyta plants which are not divided into roots,stems and leaves

Division Chlorophyta green algae

Division Phaeophyta Sargassum

Division Rhodophyta Eucheuma


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B.Embryophyta plants with roots,stems and

leaves

Division Bryophyta liverworts,

hornworts,mosses

Division Tracheophyta -vascular plants

a. Class Filicinae ferns

b. Class Angiospermae flower-

bearing plantsc. Class Gymnospermae cone-

bearing plants


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Animals may be classified as follows:

A. Phylum Porifera sponges

B. Phylum Coelenterata corals

C. Phylum Platyhelmenthis Flatworms (ex. flukes,

tapeworm)

D. Phylum Nematoda- round worms (es. Ascaris)

E. Phylum Annelida- segmented worms (ex. Leeches,

earthworms, marine worms


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F. Phylum Mollusca

shells, snails, clams, squids, octopus

G.Arthropoda crustaceans, (crabs, shrimps,

lobsters) , insects, centipedes, millepedes,

spiders, scorpions

H.Phylum Echinodermata

sea urchins, sea stars sea cucumbers, brittle

stars

I. Phylum Chordata fishes (bony and

cartilagenous), amphibians (frogs and

toads), reptiles, birds, mammals


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Classification ofDugong (Dugon dugon)

Kingdom AnimaliaPhylum Chordata

Class Mammalia

Order SireniaFamily Dugongidae

Genus Dugong

Species dugon

Dugong dugon

(Muller 1776)


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Differences Between Fish and Marine Mammals

Look at the tail:

Whales tail is horizontal

and moves up and down

While a fishs tail is vertical

and moves from side to side


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Differences between Cetacean and Dugong

Cetacean Dugong

Body more streamlined andthicker blubber Body is less streamlined, hasthinner blubber layer;

No hair Tough skin with short and

stubby hairs

Spongy bone Bones dense and thick

blowholes Nostrils at the tip of the snout

Mammary slit found between

the genital slit and anus

Mammary nipples found in

the axilla

The mouth oriented linear to

its body

The rostrum is turned

downward and mouth located

at the ventral plane

Feeds on crustacean, fish or

squid

Feeds on seagrasses


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What separates cetacea from the

suborder of baleen or whalebone(Mysticeti) and tooth whales

(Odontoceti)........?

Answer: the absence of platesand teeth


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Sex Determination in Dugong

Male

Umbilical scar, genital

slit and anus more or

less equally distant

Female

Genital slit and anus veryclose to each other than

the umbilical scar


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