Biology 2201 Unit 2 Chapter 5

Transcription

1 Biology 2201 Unit 2 Chapter Kingdom Protista (pp ) Kingdom Protista general characterisitcs and groups Protists are a very diverse kingdom of living things that do not fit into any other kingdom (Animals, Plants, or Fungi). They are all eukaryotic and most are multicellular, but beyond that this group is very different. In fact, there are 3 main groups of protists: (1) Protozoa (Animal-like protists) (2) Algae (Plant-like protists) (3) Slime Moulds (Fungus-like protists) 1

2 Protozoa (animal-like) Obtain food by feeding on other organisms, either by scavenging, predation, or as a parasite Various shapes and methods of transportation Some protozoa have very complex life cycles No cell walls; most live as single cells There are many different phyla of protozoa, including: Phylum Zoomastigina (Flagellates) Phylum Sarcodina (Sarcodines) Phylum Cilliophora (Cilliates) Phylum Sporozoa (Sporozoans) Phylum Zoomastigina (Flagellates) all have one or more flagella to move some are parasitic while others are not ex. Trypanosoma brucei causes African sleeping sickness (carried by tsetste fly) 2

3 Phylum Sarcodina (Sarcodines) Also called amoebae Move by extensions of their cytoplasm called pseudopodia (false feet) There are free-living, mutualistic, and parasitic species Amoeba - pics 3

4 Phylum Cilliophora (Cilliates) Covered with cilia which helps them move Some members free-living, some mutualistic, some parasitic - Ex. Paramecium Phylum Sporozoa All parasites All make spores at some point in their life cycle Ex. Plasmodium vivax is a sporozoan that can cause malaria. It has 2 hosts, mosquitoes and humans (see life cycle diagram, p. 146) 4

5 Plasmodium vivax life cycle Algae (Plant-like) all photosynthetic (contain chlorophyll) different sizes (from single cell to large seaweeds) seaweeds not true plants; no roots, stems or leaves Groups of Algae (a) Phylum Chlorophyta (Green algae) (b) Phylum Phaeophyta (Brown Algae) (c) Phylum Rhodophyta (Red algae) (d) Phylum Chrysophyta (Diatoms) (e) Phylum Pyrrophyta (Dinoflagellates) (f) Phylum Euglenophyta (Euglenoids) 5

6 Phylum Chlorophyta (Green algae) closest group to land plants cell walls contain cellulose some reproduce asexually while others reproduce sexually some members are unicellular and move by flagella; larger members don t move Phylum Phaeophyta (Brown Algae) Cell walls made of cellulose and alginic acid Cold water seaweeds Don t move around 6

7 Phylum Rhodophyta (Red algae) Warm water seaweeds Don t move Sexual reproduction Phylum Chrysophyta (Diatoms) most abundant group of unicellular algae; biggest component of plankton rigid cell walls with a layer of silica (like in glass) asexual and sexual production present don t move on their own; they float in water 7

8 Phylum Pyrrophyta (Dinoflagellates) Unicellular, mostly marine Have protective coats made of cellulose Each member of this group has two flagella, one to move it and the other to steer Mainly asexual reproduction, but some sexual Phylum Euglenophyta (Euglenoids) Small unicellular freshwater organisms Have 2 flagella Over half of euglenoids do not have chloroplasts and are heterotrophs 8

9 Slime Moulds and Water Moulds (Fungus-Like Protists) Water moulds (Phylum Oomycota) Filamentous organisms that resemble fungi Feed on dead matter mostly; some are parasites One species responsible for Irish Potato Famine Produces spores Plasmodial Slime Moulds (Phylum Myxomycota) look like tiny slugs they feed by engulfing small particles of food reproduce by spores Cellular Slime Moulds (Phylum Acrasiomycota) Individual cells with one nucleus Reproduce by spores Slime Moulds and Water Moulds (pics) 9