O most are autotrophs with chloroplasts water molds o

Info icon This preview shows pages 7–9. Sign up to view the full content.

View Full Document Right Arrow Icon
o Most are autotrophs with chloroplasts Water molds o Or Oomycetes Heterotrophs that form a mesh of nutrient absorbing filaments Diatoms o Diatoms= diploid, photosynthetic, single celled or colonial protists that secrete a protective silica shell. Shell consists of 2 overlapping parts that fit one inside the other, like a shoe box and its lid Some have a cylindrical shape but others are square or needlelike Usually reproduce asexually Live in lakes, seas, and damp soils Brown algae o Multicelled protists living mainly in cool, coastal waters o Have commercial uses like food or nutritional supplements 21.9 Red Algae Red algae= live in clear, warm waters and multicelled marine algae o Red because their chloroplasts contain necessary pigments that absorb blue- green and green light o Have commercial uses Agar
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Carrageenan o Two lineages of green algae Chlorophyte algae Largest lineage of green algae Include freshwater and marine species Chlamydomonas o Single celled species common in ponds Charophyte algae Charophyte= mostly freshwater group of green algae o Some are live as single-cells, others form strands of cells, and others have a complex body 21.11 Amoebozoans and Choanoflagellates Amoebozoans= lineage of heterotrophic, unwalled protists that live in soils and water & include amoebas and slime molds o Amoebas= live as single cells Predator in freshwater habitats o Slime molds Sometimes described as “social amoebas” Two types Cellular o Cellular slime molds= spend the bulk of their existence as individual haploid amoeboid cells. o Ex. Dictyostelium discoideum o Each cell eats bacteria and reproduces by mitosis When food runs out, they aggregate to form a multicelled mass
Image of page 8
Enviro gradients in light and moisture induce the mass to crawl along as a cohesive unit often referred to as a slug When slug reaches suitable spot, its component cells differentiate to form a fruiting body When spore germinates, it releases a cell that starts the life cycle anew Plasmodium o Plasmodium slide molds= spend most of life cycle as a multinucleated mass called a plasmodium. o Forms when a diploid cell divides its nucleus repeatedly by mitosis but doesn’t undergo cytoplasmic division Choanoflagellates o Choanoflagellates= thought to be the closest living protest relatives of animals. Name means “collared flagellate” Has flagellum surrounded by a collar of microvilli Sponges have cells with a similar structure
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern