Do You Know About Types of Multicellular Organism Flashcards

uni/multicellular photosynthetic protists

- classified into 3 phyla based on colour: red, brown, and green
- scientists believe that algae are evolutionary link between protists and plants

Multicellular algae, also divided into red, brown and green

Phylum Phaeophyta
- most complex protists
- lots of specialized tissue

Phylum Rhodophyta
- first multicellular organisms
- have additional pigment called phycoerythrin which allows red algae to be deep in the ocean and is sensitive to light (reflects red wavelengths of light)

Phylum Chlorophyta
- most are aquatic
- structurally diverse
- most plant-like of algae (same chlorophyll and colour)

holdfast: anchors algae
blade: used for photosynthesis
stipe: long, stem-like structure

When earliest plants moved to land, they had to adapt to:
1. protect themselves from drying out
2. find a different transport system other than osmosis and diffusions
- plant embryos had to adapt to terrestrial and were used to reproduce
- vascular tissue developed from osm. and diff. = xylem (water, up) and phloem(nutrients, up & down)
- alternation of generations/sporic reproduction: sexual reproduction between gamete-making ind. and spore-making ind.
- two multicellular stages in life cycle

- haploid version of plant/gametophyte produces hap. gametes by mitosis
- when gametes fuse, they become diploid version of plant/sporophyte
- sporophyte makes spores via meiosis which turn back into hap. gametophyte

Have 3 phyla: mosses, liverworts, and hornworts
- depend on osmosis (water crossing cell membrane) and diffusion (molecules moving in and out of cell)
- do not have roots, instead have rhizoids which are root-like

Gametophyte Generation(dominant)
- spores are made by sporophyte via meiosis and when dispersed, they germinate turn into male and female gametophyte
- male gametophyte develops into antheridium (produces sperm)
- female gametophyte develops into archegonium (produces eggs)
- sperm swims to arch. (same plant) and fertilizes
Sporophyte Generation
- zygote is made, and new sporophyte is made
- sporophyte releases spores and cycle goes on

Have 4 phyla: whisk ferns, club mosses, horsetails, and ferns
- formed the first forests

Gametophyte Generation
- haploid spores germinate to become a prothallus (gametophyte, has both arch. and anth.)
- sperm from anth. swims to anth. via water droplet and fertilizes
- zygote forms by mitosis and becomes a sporophyte ontop of gametophyte
Sporophyte Generation (dominant)
- roots and fronds grow
- spores are formed in sori by meiosis and releases hap. spores

- allows plants to reproduce sexually without water
- provides protection
- used to disperse plants

Diversity: conifers/evergreens, cycadophytes, ginkgophytes
Reproduction: cones
- male are soft and short-lived
- female are long and longer-lasting
- to transport sperm to eggs, pollen grains are released into wind and some land on female cones

Tiny gametophytes that don't germinate and form a gametophyte