Lecture 11 Flashcards
Levels of Organismal Complexity
- Protoplasmic
- Cellular
- Cell-tissue
- Tissue-organ
- Organ-system
Protoplasmic
Unicellular organisms (e.g. protozoans)
Colonial
Cellular;aggregation of undifferentiated cells
Multicellular
Cellular;
aggregation of cells that are functionally different
Cell-tissue organismal complexity
- 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
- e.g.cnidarians,some sponges
Tissue-organ organismal complexity
- Organs contain more than one type of tissue(e.g. gonads, lungs, heart)
- More specialized function
- e.g.platyhelminthes
Organ-system organismal complexity
• Organs work together in a system(e.g.reproductive,
respiratory, circulatory)
• e.g. other eukaryotes
Kingdom Fungi chracteristics
• Unicellular and multicellular species
• Fungi do not have chlorophyll
• Have cell walls (like plants), but these are composed of
chitin, not cellulose
• Important ecological function - decomposers
Chitin
In cell wall of fungi, is a nitrogenous polysaccharide
Tough, protective substance, also found in the exoskeleton of arthropods
Chemoheterotrophs
Animals + fungi
Chemoautotrophs
some prokaryotes (e.g. extremophiles)
Photoheterotrophs
some prokaryotes (e.g. purple and green non-sulfur bacteria)
Photoautotrophs
plants, algae, cyanobacteria
Nutrition in Fungi
- Extracellular digestion
* Release digestive enzymes into the environment and then absorb nutrients through their cell walls
Porifera characteristics
Porifera=sponges Simplest multicellular metazoans No organs or true tissues No nervous system or sense organs Adults sessile and attached Limited body movement
What type of symmetry to poriferas have?
Radial symmetry or no symmetry
Are there land porifera?
NO! All sponges are aquatic and mostly marine
Basic Form of porifera
Only body openings are pores
• Many tiny ostia (singular = ostium) for incoming water
• One to several large oscula (sing. = osculum) as water outlets
• Openings can be connected by canals
• Three basic forms
Three basic forms of porifera
Asconoid – flagellated spongocoel
Syconoid – flagellated canals
Leuconoid – flagellated chambers
Asconoid sponges
Flagellated spongocoel
- Water enters through ostia into spongocoel
- Spongocoel is lined with choanocytes
- Water is pulled out of a single large osculum
Syconoid Sponges
Flagellated Canals
• Water movement
• In through incurrent canals
• into radial canals through prosopyles
• into spongocoel through apopyles
• exits through osculum
• Radial canals are lined with choanocytes
Leuconoid Sponges
Flagellated Chambers • Most have numerous oscula • No spongocoel • Incurrent and excurent canals • Flagellated chambers are lined with choanocytes
Choanocytes
in porifera
Flagellated collar cells
• One end embedded in mesohyl, other end exposed
• Move water, collect food particles and consume by phagocytosis
Cell Types in porifera
- Arranged in layers (choanoderm and pinacoderm)
* Or loosely arranged in the mesohyl (extra- cellular matrix)
Pinacocyte:
in porifera
Epithelial type cells
Closest thing to a tissue in a sponge
Porocytes
in porifera
Pore cells
Only in asconoid sponges
Archaeocyte
in porifera Amoeboid cells Move through mesohyl Receive particles for digestion from choanocytes Transport food to other cells Transport oxygen to other cells
Skeleton Types in porifera
Fibrils of collagen
spongin
spicules
Fibrils of collagen
support in porifera
occur through ECM of all sponges
Spongin in porifera
• a form of collagen secreted by Class Demospongiae
• Forms the skeletal network of some sponges
skeleton type
Spicules in porifera
• Many different shapes – can be used to classify sponges
Skeleton type
Sponge Physiology
Feed on particles
Respiration and excretion by diffusion
Archaeocytes transport oxygen, nutrients to other parts of the sponge
Dependent on a current of water flowing through body
Sponge Reproduction
• All reproduce both sexually and asexually
• Most sponges are monoecious in sexual
reproduction
Asexual reproduction in porifera
- Fragmentation
- Budding
- Gemmulation
Sexual Reproduction
in porifera
• Sperm and oocytes can develop from choanocytes (or sometimes archaeocytes)
• Most sponges are viviparous
Sperm released into water
taken up into the canal system of another individual
Choanocytes phagocytize the sperm, and carry them through the mesohyl to the oocytes
Zygote is retained in parent
A ciliated larva is released (indirect development)
• Some sponges are oviparous
Oocytes and sperm are released into water
