Fungi and Porifera Flashcards
What are the levels of organismal complexity?
- Protoplasmic
- Cellular
- Cell tissue
- Tissue organ
- Organ system
What is protoplasmic?
unicellular organisms
What is cellular?
- Can be
Colonial = aggregation of undifferentiated cells
Multicellular = aggregation of cells that are functionally different
What are cell-tissue?
- Cells aggregate into patterns or layers
- Tissue = group of similar cells organized to perform a common function
- True tissue secretes extracellular matrix in form of a basement membrane on which cells sit
What are tissue-organ?
- Organs contain more than one type of tissue
- More specialized function
What are organ-system?
Organs work together in a system
Examples from the kingdom fungi
Yeasts
Rusts and Smuts
Mould anf Mildew
Mushrooms
What is the kingdom fungi?
- Unicellular and multicellular species
- Originally classified as plants (fungi do not have chlorophyll)
- Have cell walls, but these are composed of chitin, not cellulose
Chitin is a nitrogenous polysaccharide - Important ecological function (decomposers)
Photoautotrophs
plants, algae, cyanobacteria
Photoheterotrophs
some prokaryotes
chemoautotrophs
some prokaryotes
chemoheterotrophs
animals, fungi
What is the nutrition in fungi?
- Extracellular digestion
- Release digestive enzymes into the environment and then absorb nutrients through their cell walls
Why are Porifera interesting?
- These are sponges
- Simplest multicellular metazoans
- May seem like plants (they are animals)
- Common household object
- Beautiful shapes and colours
Intro to Phylum Porifera
- No organs or true tissues
- No nervous system or sense organ
- Adults sessile and attached
- Limited body movement
- High totipotency
- All are aquatic (mostly marine)
- Radial symmetry or no symmetry
What is a sponge?
An assemblage of cells embedded in an extracellular matrix and supported by a skeleton of minute needlelike spicules and protein
What is the extracellular matrix (ECM)?
A collection of extracellular molecules secreted by support cells that provides structural and biochemical support to the surrounding cells
What is the basic form?
- Only body openings are pores
Many tiny Ostia for incoming water
One to several large oscula as water outlets
- Openings can be connected by canals
- Three basic forms
Asconoid (flagellated spongocoel)
Syconoid (flagellated canals)
Leuconoid (flagellated chambers)What is asconoid sponges?
- Water enters through ostia into spongocoel
- Spongocoel is lines with choanocytes
- Water is pulled out of a single large osculum
- Small and tube shaped
- Size limited (large spongocoel would create dead space)
What is a syconoid sponge?
- Water movement
In through incurrent canals
Into radial canals through prosopyles
Into spongocoel through apopyles
Exits through osculum - Radial canals are lined with choanocytes
- Same as asconoid but the body wall is evaginated to form canals
What is a leuconoid sponge?
- Most have numerous oscula
- No spongocoel
Incurrent canals
Flagellated chambers
Excurrent canals - Flagellated chambers are lined with choanocytes
- Increased efficiency
- Can grow bigger
Cell Types
- Cells are
Arranged in layers (choanoderm and pinacoderm)
Or loosely arranged in the meshy (ECM) - Small section through sponge wall, showing 4 types of sponge cells. Pinacocytes are protective and contractile; choanocytes create water currents and engulf food particles; archeocytes have a variety of functions, including phagocytosis of food particles and differentiation into other cell types.
What are the cell types?
Pinacocyte
Porocytes
Choanocytes
Archaeocyte
What are pinacocyte?
- Epithelial type cells
- Closest thing to a tissue in a sponge
What are porocytes?
- Pore cells
- Only in asconoid sponges
What are Choanocyte?
- Flagellated collar cells
- One end embedded in meshy, other end exposed
- Move water, collect food particles and consume by phagocytosis
- Exposed end: flagellum surrounded by a collar of microvilli
- Collar forms a filtering device for food particles
- Food ingested by phagocytosis
What are Archaeocyte?
- Amoeboid cells
- Move through mesohyl
- Receive particles for digestion from choanocytes
- Transport food to other cells
- Transport oxygen to other cells
Skeleton types
- Skeleton prevents collapse of canals and chambers
- Fibrils of collagen occur through ECM of all sponges
Collagen is a major structural protein for metazoans
Found in hair, nails, and many other tissues in humans - Spongin
A form of collagen secreted by Class Demospongiae
Forms the skeletal network of some sponges - Spicules
Many different shapes - can be used to classify sponges
What is the sponge physiology?
- Feed on particles suspended in the water
- Respiration and excretion are performed by diffusion
- Archaeocytes transports oxygen, nutrients to other parts of the sponge
- Dependent on a current of water flowing through body
What is diffusion?
Movement of particles or molecules form an area of high concentration to an area of low concentration oxygen in carbon dioxide out
What is the reproduction of sponges?
- All reproduce both sexually and asexually
- Most sponges are monoecious in sexual reproduction
Explain the asexual reproduction
- Fragmentation
- Budding
- Gemmulation
Dormant masses that form under unfavourable conditions
Can survive drought, freezing, no oxygen
When favourable conditions return, Archaeocytes within
gemmules escape and develop into new sponges
Explain the sexual reproduction
- Sperm and oocytes can develop from choanocytes (or sometimes archaeocytes)
- Most sponges are viviparous
Sperm release in water
Taken up into the canal system of another individual
Choanocytes phagocytize the sperm, and carry them through
the meshy to the oocytes
Zygote is retuned in parent
A ciliated larva is released (indirect development) - Some sponges are oviparous
Oocytes and sperm are released into water
What is the ecological relationships?
- Other animals grow in or on sponges
Commensals or parasites
Living hotels
- Sponges grow on other animals
- Unappetizing to potential predators
- Decorator crab
Sponge crab
