170 likes | 400 Views
red algae. no flagella (evol. loss) autotrophs & parasites red pigment phycoerythrin absorbs blue light—deep agar from wall subst. also carrageenan (food) unicellular or filamentous. green algae.
E N D
red algae • no flagella (evol. loss) • autotrophs & parasites • red pigment phycoerythrin • absorbs blue light—deep • agar from wall subst. • also carrageenan (food) • unicellular or filamentous
green algae • same accessory pigments as plants: chlorophyll b (green ) & carotenoids (yellow/orange/red) • several groups, many body forms
unicellular + multinucleate = coenocytic “common cell” organism is coenocyte examples: Penicillus Caulerpa (some sp. invasive) both coenocytes = 1 cell!
alga singular algae plural a green snow alga that looks red Chlamydomonas with red carotenoid pigments that protect from UV light
charophycean green algae closest relatives of plants
amoebas examples with fat & thin pseudopodia
giant unicellular amoeba Gromia 1 inch in diameter on sea floor http://www.utexas.edu/news/2008/11/20/giant_protist/ Matz et al., Giant Deep-Sea Protist Produces Bilaterian-like Traces, Current Biology (2008), doi:10.1016/j.cub.2008.10.028
slime molds myxomycetes = “slime fungi” cellular slime mold • 1. Cellular • Unicells may aggregate • multicellular? • 2. Plasmodial (“the blob”) • plasmodium --netlike body • (amoeboid) decomposers
plasmodium of plasmodial slime mold coenocyte. streaming cytoplasm, large surface area one big cell! sporangia
sexual reproduction • haploid: having 1 set of chromosomes • diploid: having 2 sets of chromosomes • polyploid: having >2 sets of chromosomes
sexual reproduction • mitosis: division of nucleus to form 2 nuclei w/same no of chromosomes of original nucleus • meiosis: division of nucleus to form 4 nuclei w/half no. of chromosomes of original nucleus
sexual reproduction • fertilization (syngamy): fusion of 2 gametes to form 1 zygote • isogamy: gametes same form and size • anisogamy: gametes same form, different size • oogamy: large non-motile gamete (egg) & small motile gamete (sperm)
Life cycle terms • alternation of generations: life cycle with at least 2 multicellular phases that can be distinguished by reproductive cells and sometimes by morphology • spore: a reproductive cell capable of growing into a new organism w/out fusing with another cell
Life cycle terms • sporophyte: multicellular spore-producing phase of organism with an alternation of generations • gametophyte: multicellular gamete producing phase of organism with an alternation of generations
Life cycle terms • heteromorphic (“other form”) generations look different • isomorphic (“same form”) generations look the same • alternation of heteromorphic or isomorphic generations
gametes n n 2n 2n zygote humans Chlamydomonas Fig 28.22 3 Life Cycles Fig 13.6 gametophyte mitosis mitosis spores gametes n meiosis syngamy 2n zygote sporophyte mitosis kelps, plants Fig 28.16