Lesson 5b. Introductn to Metazoans; Phylum Porifera

Sponges and Placozoans

Origin of Metazoa (Animal kingdom)

Evolution of Metazoa

Evolution of Eukaryotic cell followed by diversification

Protozoa, plus multicellular animals

modern descendants of Metazoa

Multicellular animals

referred to collectively as metazoans

Choanoflagellates

solitary or colonial aquatic eukaryotes

choanocytes microvilli

Each cell (_____) has a flagellum surrounded by colar of _____

Flagellum

Beating the _____ draws water into collar

Microvilli

____ collect mostly bacteria

Most are sessile

one species attaches to floating diatom colonies

Choanoflagellates

strongly resemble sponge feeding cells

Choanoflagellates

much debate whether sponge choanocytes are ancestral to choanoflagellates

filter feeders

sessile sponges are _____

pore bearing

Porifera means "_____"

Porifera

sac like bodies perforated by many pores

Porifera

use flagellated collar cells or choanocytes to move water

Porifera

body is efficient aquatic filter

Porifera

approximately 15,000 species of sponge

• most are marine -few lives in brackish water, 150 in freshwater

seas

marine sponges found in all ____ at all depths and vary greatly in size

Dermal cells

many species are brightly colored because of pigments in ________

Embryos

_____ are free swimming, adult sponges always attached

Phylum porifera

some appear radially symmetrical but many are irregular in shape

Phylum Porifera

some stand erect, some are branched and some are encrusting

phylum Porifera, many live as ______ or ____ in or on sponges

• also grow on a variety of other living organisms

noxious odors

Few predators sponges may have an elaborate skeletal structure and often have ____

fibrous or rigid

skeletal structure of a sponge can be ____ or _____

calcareous or siliceous spicules

if skeletal is present, rigid skeleton consist of ____ or ____

Collagen fibrils, spongin

Fibrous portion _____ in intercellular matrix several types of one form or collagen ____ exist

Composition and shape the spicules, classification

_______ forms the basis of sponge _____

small incurrent pores or dermal ostia

Phylum Porifera body openings consist of ____ or ____

choanocytes

Inside the body of Phylum Porifera, water is directed past the ______where food particles are collected

Choanocytes

______ ( flagellated collar cells) line some of the canals

Asconoids, syconoids and leuconoids

Types of canal system

Asconoids

simplest body form

Asconoids

small and tube shaped

spongocoel

Asconoids water enters a large cavity, the _____

choanocytes

Asconoids is lined with ____

choanocyte flagella

asconoids _____ pull water through

Asconoids

All calcarea are ____

Leucosoleniaand Clathrina

Asconoids examples:

Syconoids (flagellated canals)

resemble asconoids but larger with a thicker body wall

choanocyte-lined radial canals

syconoids wall contains ______ that empty into spongocoel

spongocoel

Syconoids _____ is lined with epithelial cells rather than choanocytes

choanocytes

Syconoids food is digested by ____

Leuconoids Oscula

________most complex and are larger with many _____

leuconoids, chambers

________clusters of flagellated _____ are filled from incurrent canals, and discharge to excurrent canals

leuconoids

most sponge are ___

the leuconoid system

evolved independently many times in sponges

Leuconoids

system increases flagellated surfaces compared to volume

• more collar cells can meet food demands

• large sponges filter 1500 liters of water per day

Asconoids syconoids leuconoids

types of canal system

Choanocytes Archaeocytes Pinacocytes ​

Types of cells in Phylum Porifera:

sponge cells, mesohyl

_____ are arranged in a gelatinous matrix _____

mesohyl

connective tissue of sponges

slight alterations in shape, local contractions, and closing and opening of incurrent and excurrent pores -movements occur very slowly

only visible activities of sponges are:

Phylum Porifera, unknown mechanism

________apparently excitation spreads from cell to cell by an _____

Choanocytes

oval cells with one end embedded in mesohyl

Choanocytes, collar

____ exposed End has one flagellum surrounded by a ____

adjacent microvilli

choanocytes collar consist of _____

Microvilli

_____forms a fine filtering device to strain food

mucuous

choanocytes particles too large to enter collar are trapped in _____

Archaeocytes

Food engulfed by choanocytes is passed to _____ for digestion

Archaeocytes

• move about in the mesohyl

• phagocytize particles

• can differentiate into any other type of cell

Pinacocytes

form pinacoderm

Pinacocytes

flat epithelial-like cells

Pinacocytes

somewhat contractile and help to regulate flow of water

Cell independence (Regeneration)

Sponges have a great ability to regenerate lost parts and repair injuries

Reorganization

process of _______ differs in sponges of differing complexity

asexual reproduction

regeneration followed by fragmentation is one means of _______

Budding, External buds and Internal Buds

Asexual reproduction can occur by _____ 1____ and 2____

External buds

small individuals that break off after attaining a certain size

Internal buds (gemmules) archaeocytes

________formed by _______ that collect in mesohyl

Spongin and Spicules

Internal buds is coated with tough _____ and ____

internal buds (gemmules)

survive harsh environmental condition

sexual reproduction

most are monoecious

Zygote, ciliated larva

sponges provide nourishment to ______ until it release as a _____

sperm

in some, one sponge releases ______ which enter the pores of another sponge

Sperm and oocytes

Some sponge releases both ____ and _____ into water

Parenchymula

Free swimming larva of sponges is a solid ______

Class, Calcarea, Class Hexactinellida, and class Demospongiae

Classification of Phylum Porifera:

Calcispongiae

Class Calcarea is also called ____

calcium bicarbonate

Calcareous sponges with spicules of _______

Spicules

____ are straight or have three or four rays

Class Calcarea

most arre small with tubular or vase shapes

Class Calcarea, yellow, green, red, or lavender

class ______, Many are drab in color, but some are bright ,_,_____, or ____

Leucosolenia and Sycon

_____ and ____ are marine shallow-water

Asconoids, Syconoids, Leuconoids

Class Calcarea body form: 3

Hyalospongiae

Class Hexactinellida is also called ____

Class Hexactinellida

glass sponges with six-rayed siliceous spicules of silica

Class Hexactinellida

Nearly all are deep-sea forms

Class Hexactinellida

Most are radially symmetrical

Class Hexactinellida, substrate

Class ______stalks of root spicules attach them to _____

Syconoids and leuconoids types

Class Hexactinellida chambers appear to correspond to both ___ and ____ types

Class Hexactinellida

adapted to a deep-water habitat with a large and easy flow of water

Class Demospongiae

contains 95% of living sponge species

Spicules, spongin

(Class Demospongiae) _______are siliceous but not six rayed

• absent or bound together by ____

Spongillidae

Spongillidae

Freshwater sponges

-Widely distributed in well-oxygenated ponds and springs

Genotype, gemmules

Reproduce sexually, but existing _____ may also reappear annually from _____

Marine demosponges

Highly varied in color and shape

Bath sponges

Lacks siliceous spicules, Have spongin skeletons

Cambrian

Sponges appeared before the ______