phylum porifera Flashcards
what type of feeders are sponges ?
almost all suspension feeders (filter feeders)
exception to suspension feeding sponges
cold water deep carnivorous sponges - Chondrocladia grandis
prey on planktonic crustaceans
what is multicellularity ?
a condition or state of having or being composed of many cells — with more than one cell type performing different functions
possible evolutionary progression of multicellularity characteristics
- cell adhesion (cells become selective)
- cell specialization and interdependence
- embryonic differentiation
what are the advantages of multicellularity? why did it develop ?
- cells can perform all life functions more efficiently due to specialization
- larger body sizes and more complex body types can be achieved w this, positive competitive advantage
- the diversity of body sizes and types opened up much larger range of habitat niches (not avail to unicellular) - in relation to temp, pH, chemical availability etc)
metazoan tissue types
- epithelial tissue
- connective tissue
- nervous tissue
- muscle tissue
- gametogenic tissue
defining characteristics of epithelial tissue
- forms tight and regular cell sheets (cellularity)
- have a dictated direction (polarity)
- is surficial layer for other cells (attachment)
- have no blood cells (avascular)
- show rapid growth (regeneration)
functional importance of epithelial tissue
- transitional covering on all internal and external surfaces on body
- lines body cavities and hollow organs - is the major tissue in glands
- performs protection (skin), secretion (glands), absorption, excretion, filtration, diffusion, and sensory reception
connective tissue defining characteristics:
- formed by an abundant intercellular matrix with relatively few connecting cells
- contains collagen (the main structural protein - most abundant protein in mammals) — whats being released when making bone broth
functional importance of connective tissue
- binding and holding other tissues together
- supporting and protecting individuals organs
- provides elasticity for movement (ex// cartilage)
defining characteristics of nervous tissue
- ropelike linear or branching bundles in structure
- fibers are excitable - capable of sending and receiving electrochemical signals
- comprised of neurons and neuroglial cells - glial cells supporting the neural structures
functional importance of nervous tissue
- generate and conduct sensory or motor impulses between the brain or spinal cord
- provides all parts of the body w information, and controls both voluntary (movement) and autonomous body functions (digestion)
defining characteristics of muscular tissue
- ability to shorten and lengthen
- highly cellular and highly vascular (supplied well w blood vessels)
- often have elongated nuclei
functional importance of muscular tissue
- contractions produce movement of body parts
- must work w nervous tissue for stimulus
- used for heat generation and fluid distribution functions (ex// blood)
defining characteristics of gametogenic tissue
- haploid (n) or one set of chromosomes. ONLY tissues that are haploid
- produced by dedicated diploid (2n) germ cells which undergoes meiosis that forms haploid cells
- typically sexually dimorphic — male gamete smaller in size and motile — female gamete several times bigger and non-motile