BI256 Study Guide - Final Guide: Zygote, Strobilation, Calcareous Sponge

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4 Apr 2017
Lab 1: Protozoan Organisms
Protozoans are unicellular and simple (eukaryotes). Capable of performing locomotion, food capture,
ingestion, digestion, egestion, respiration, excretion, osmoregulation, and reproduction.
Two animal-like properties: (1) Absence of a cell wall (2) Presence of one motile stage in life
Phylum Amoebazoa
-Locomotion by pseudopodia (false foot) or by protoplasmic flow without discrete pseudopodia
-Asexual reproduction by binary fission. Most are free-living but there are also free-living types
The Naked Amoebae
-Mainly fresh-water and parasitic naked amoeba, typically uninucleate.
-Commonly found in organic debris in fresh-water ponds and slow-moving streams where it ingests other
protozoa, bacteria, and diatoms. Reproduce by binary fission
Internal Features
i)A Peripheral Ectoplasmic layer: confined by the PM and composed of an outer clear layer of cytoplasm and an
inner layer of motionless granules
ii) An inner endoplasmic layer of moving granules
b) Nucleus: a slightly ovoid structure near the center of the organism
c) Food Vacuoles: small, dark, food-filled areas within the cytoplasm
d)Contractile Vacuole: clear, spherical, fluid-filled vacuole carried near the organism’s “rear end’ or uroid.
Phylum Euglenoza
-Plant-like flagellates, pigmented chloroplasts used in photosynthesis (holophytic)
1.Pellicle, thin, semi-rigid convering
2. Reservoir-clear, flask-shpaed space at anterior end
3.Chloroplasts-with green chlorophyll
4.Nucleus-Exhibiting a large central nucleolus
5.Contractile vacuole-Empties excess water into reservoir
6.Stigma-a light-sensitive receptor at the anterior end
7.Flagellum-long whip like at anterior end
Osmoregulation ( Paramecium-Ciliophora )
-Many live in hypotonic medium (lower concentration of salts and other molecules
than their cytoplasm). Protozoan dispose of this water by a special water balance system, the contractile
vacuole and its auxilary canals and vesicles. Expel it to the exterior via a small permanent pore
Vorticella-Asexual reproduction: by binary fission. Conjugation takes place, encystment occurs under adverse
-Contraction is brought about by the contraction of the myoneme. Pellicle contains no trichocysts and bears
no cilia
Lab 2: Porifera and Cnidarian Organisms
-Little or no tissue organization. Cellular level of organization (Phylum Porifera)
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