Notes - Protists Continued
II. Algae (plant-like)
o Eukaryotes
o Contain _chlorophyll__ and produce _oxygen_ as a byproduct of Photosynthesis
o Many are __unicellular_, but some are multicellular
o Some are __colonial_ (they live as a group with each cell having specific
functions.
Two groups of algae: Unicellular and Multicellular
1. Unicellular Algae
They are classified by the type of outer _covering_ and _movement_.
Dinoflagellates – These are unicellular algae with __2__ flagella used to spin
the cell through water. They are covered with _cellulose__ __plates__ and the
majority live in saltwater habitats. These are responsible for “_red_ _tides__”.
Diatoms – These are algae that lack both _cilia_ and _flagella_ and
have _glass-like__ cell walls containing silica. They come in a variety of
shapes and patterns. Since they have _rigid_ cell walls, they have pores that
allow gases and other materials to pass through. They are the most
_abundant_ organisms in the ocean. Many are used as abrasives in polishing
agents, detergents, and toothpastes.
2. Multicellular Algae
Were once classified as plants because of _chlorophyll__ and photosynthesis,
but they are classified as protists because they have different
_reproductive_ structures from plants.
They are not necessarily microscopic.
Green Algae – Also called _XXXXXXXX_. Most live in _fresh water_, but some
live in the ocean. Either grow as filaments, linked end to end, or as flat leaf-like
cells.
Example: _XXXXXXX_ (ponds and moist soil) It has flagella that can be
retracted when it becomes dormant.
__Volvox__ (common colonial green algae) Live in ball-shaped colony.
Some green algae live in symbiotic relationships with fungus = _Lichen__
Red Algae – Also called _XXXXXXXX___. They grow in warm, saltwater
habitats. Not all of them are red, some can be orange, green, brown, and black.
Can carry out photosynthesis at _great _ __depths__ because of the
different __pigments_ other than chlorophyll. Very important for coral reefs.
Brown Algae – Also called Phaecophyta. Grow in cool, saltwater habitats.
Example: _Kelp_ These have root-like structures that keep them anchored.
These also have specialized air bladders to help them float.
Algae are also a large component of plankton, but they are the part of plankton
referred to as _phytoplankton__ because they carry out photosynthesis.
III. Fungus-like protists
Divided into 3 groups: Plasmodial Slime Molds; Cellular Slime Molds; Water
Molds.
Decomposers recycle organic material into the environment. They extract their
nutrients from _dead__ organic materials.
1. Plasmodial Slime Molds (_slimy__ or wet in appearance)
Many different colors.
They assume different forms during their life cycle.
__Plasmodium___ – The feeding stage; during this phase the mold forms
a mass of cytoplasm similar to amoeba. It feeds on _bacteria_ and other
small organisms.
__Spores_ – When conditions are not good for __feeding_, the mold stops
feeding and forms a body that produces spores.
When conditions improve, the spores are released and develop into
plasmodium again.
2. Cellular Slime Molds (slimy or _wet___ in appearance)
Alternates between stages similar to plasmodial slime mold, but forms
_pseudoplasmodium___ “false plasmodium” when food is scarce.
3. Water Molds (includes white rusts and downy mildews)
They are decomposers or parasites.
They typically grow in freshwater on decaying _fish__ and __plants__.
They are not true fungus because:
- Their cell walls contain _cellulose__ instead of _chitin_.
- Their spores have _flagella_ whereas true fungi produce spores without
_flagella__.
*****Water Mold caused the Irish Potato Famine