Animal Kindgom 2 Flashcards
what is the habitat, ssymmetry and level of org. of porifera
Members of this phylum are commonly known
as sponges. They are generally marine and mostly
asymmetrical animals (Figure 4.5). These are
primitive multicellular animals and have cellular
level of organisation.
Examples: Sycon (Scypha), Spongilla (Fresh water sponge) and Euspongia
(Bath sponge).
explain the tsructure of phylum porifera
Sponges have a water
transport or canal system.
Water enters through
minute pores (ostia) present all over the body wall into a central
cavity, spongocoel,. The large opening through which waste material exits is called osculum
This pathway of water
transport is helpful in food gathering, respiratory
exchange and removal of waste.
Choanocytes
or collar cells line the spongocoel and the canals. They pick up the food ie planktons
Digestion is intracellular. The body is supported
by a skeleton made up of spicules or spongin
fibres.
what is the fertilisation and develomental stages of porifera
Sexes are not separate (hermaphrodite and monoecious),
i.e., eggs and sperms are produced by the same
individual. Sponges reproduce asexually by
fragmentation and sexually by formation of
gametes. Fertilisation is internal and development
is indirect having a larval stage which is
morphologically distinct from the adult.
what are coelentrates or cnidaria
They are aquatic, mostly marine, sessile or free-swimming, radially
symmetrical animals (Figure 4.6).Cnidarians
exhibit tissue level of organisation and are diploblastic. Some of the cnidarians, e.g.,
corals have a skeleton composed of calcium carbonate.
justify the names ceolenterata and cnidaria
i) They have a central gastrovascular cavity called coelentron and a single opening called the hypostome. hence they are called coelenterates
ii) They have cnidoblasts or cnidocytes (which contain the stinging capsules or
nematocysts) present on the tentacles and the body. Cnidoblasts are used
for anchorage, defense and for the capture of prey
what is the digestion and fertilisation of cnidarians
Digestion may be both intracellular and extracellular
because the big preys are broken down outside the body and ten taken in and digested internally.
Thy have internal fertilisation and monoecious
how can cnidarians be clasified on basis of orientation
i) Polyps
They are grounded, sedentary and sessile, cylindrical and have tentacles upward
ii) Medusa
They are free swimming, motile, umbrella shaped and have tentacles downward
iii) Metagenesis
is the phenomenon of existence of two life forms( medusa and polyp) both alternating with each other in life cycle
i.e., polyps produce medusae asexually and
medusae form the polyps sexually (e.g., Obelia).
Examples: Physalia (Portuguese man-of-war), Adamsia (Sea anemone),
Pennatula (Sea-pen), Gorgonia (Sea-fan) and Meandrina (Brain coral).
explain ctenophores
Ctenophores, commonly known as sea walnuts or comb jellies
are exclusively marine, radially symmetrical, diploblastic
organisms with tissue level of organisation.
The body bears
eight external rows of radial ciliated comb plates, which help in
locomotion. It also has tentacles lined with sticky cells called colloblast for catching prey,
Digestion is both extracellular and
intracellular.
Bioluminescence (the property of a living
organism to emit light) is well-marked in ctenophores.
Sexes
are not separate. Reproduction takes place only by sexual
means. Fertilisation is external with indirect development.
Examples: Pleurobrachia and Ctenoplana.
explain the platyhelminthes
They have dorso-ventrally flattened body, hence are called
flatworms (Figure 4.9). Flatworms are bilaterally
symmetrical, triploblastic and acoelomate animals with organ
level of organisation.
These are mostly endoparasites found
in animals including human beings.they may be free living. Hooks(anchorage) and suckers(drawig nutrient from host tissue) are present in the parasitic forms. Some of them absorb nutrients from the host directly through their body surface.
Tthey have a digestive tube for one opening.
Specialised cells called
flame cells help in osmoregulation and excretion.
Sexes are not
separate. Fertilisation is internal and development is through
many larval stages. Some members like Planaria possess high
regeneration capacity.
Taenia solium, fasciola hepatica
The body of the aschelminthes is circular in
cross-section, hence, the name roundworms
(Figure 4.10). They may be freeliving, aquatic
and terrestrial or parasitic in plants and animals.
Roundworms have organ-system level of body
organisation. They are bilaterally symmetrical,
triploblastic and pseudocoelomate animals.
Alimentary canal is complete with a well-
developed muscular pharynx. An excretory
tube removes body wastes from the body cavity
through the excretory pore.
Sexes are separate
(dioecious), i.e., males and females are distinct.
Often females are longer than males. Fertilisation
is internal and development may be direct (the
young ones resemble the adult) or indirect.
Examples : Ascaris (Roundworm), Wuchereria
(Filaria worm), Ancylostoma (Hookworm).
explain the structure of annelida habitat also
They may be aquatic (marine and fresh water) or
terrestrial; free-living, and sometimes parasitic.
They exhibit organ-system level of body
organisation and bilateral symmetry. They are
triploblastic, metamerically segmented and
coelomate animals. Their body surface is
distinctly marked out into segments or
metameres which look like little rings and, hence, the phylum name
Annelida (Latin, annulus : little ring)
what is the organs present in annelida
They possess longitudinal and circular muscles
which help in locomotion.
Aquatic annelids like
Nereis possess lateral appendages, parapodia,
which help in swimming.
A closed circulatory
system is present.
Nephridia (sing. nephridium) are excretory structures which help in osmoregulation and excretion.
Neural
system consists of paired ganglia (sing. ganglion)
connected by lateral nerves to a double ventral
nerve cord.
what is the annelids gender and fertilisation
Nereis, an aquatic form, is dioecious,
but earthworms and leeches are monoecious.
Reproduction is sexual.
Nereis, Pheretima (Earthworm) and
Hirudinaria (Blood sucking leech).
what are basic features of arthropods
This is the largest phylum of Animalia which
includes insects. Over two-thirds of all named
species on earth are arthropods (Figure 4.12).
They have organ-system level of organisation.
They are bilaterally symmetrical, triploblastic,
segmented and coelomate animals.
what are diagnostic features of arthropoda
The body
of arthropods is covered by chitinous
exoskeleton whcih gives a glazy look.
The body consists of head, thorax
and abdomen. They have jointed appendages
(arthros-joint, poda-appendages).
Respiratory
organs are gills, book gills, book lungs or
tracheal system( tracheal tubules, spiracles and air sacs).
Circulatory system is of open
type. Blood diffuses ito open spaces and hence coelom is callled haemocoel.
Sensory organs like antennae, eyes
(compound and simple), statocysts or
balancing organs are present.
Excretion takes
place through malpighian tubules. They
