27.3 How do Protists affect the world around them.
-
Pros:
Diatoms alone are responsible for
1/5 of carbon fixation
Provide nutrients to coral
Provides habitat for other
organisms
Flagellates live inside termites,
digesting wood
-
-
Cons:
Plasmodium protists cause malaria
Trypanosomes cause sleeping
sickness, leishmaniasis, dysentery
Algae blooms can suffocate other
organisms
Termites cost a lot of $$$
27.4 How do Protists Reproduce
Some protists reproduce without sex,
and have sex without reproducing…
Binary Fission – Equal splitting of one cell into 2, with mitosis followed
by cytokinesis
Multiple Fission – Splitting of one cell into more than two cells
Budding – The outgrowth of a new cell from the surface of an old one
Spores – The formation of specialized cells that are capable of
developing into new organisms
Conjugation – the process by which nuclear material is exchanged over
a period of several hours between two protists of the same species by
means of their oral groove. The result is 2 haploid micronuclei (one
from each of the protists) that will fuse to form a new macronucleus.
Alteration of Generations – In some protists’ life
cycles, the generations will alternate between sporeproducing (diploid) and gamete-producing(haploid).
Heteromorphic Generation – The generations differ in
appearance.
Isomorphic Generation – The generations look
identical, but have different genetic differences.
27.5 What are the Evolutionary Relationships Among Eukaryotes?
Five Major Clades: Chromalveolates, unikonts, rhizaria, excavates, & Plantae
Chromalveolates: usually have cellulose in their walls, are
photosynthetic, and include haptophytes (unicellular and
have one flagella), alveolates (have sacs under
membrane), and stramenopiles (2 unequal flagella).
Unikonts: have only one flagella.
Unikonts consist of amoebozoans (use
lobe shaped pseudopods for movement)
and opisthokonts (which includes
animals and fungi). Opisthokonts have a
posterior flagella, while all others are
anterior.
27.5 What are the Evolutionary Relationships Among Eukaryotes
Rhizaria: are unicellular and
aquatic. It incudes cercozoans,
foraminiferans, and radiolarians.
Excavates: lack mitochondria. These
eukaryotes either split off before the
acquisition of mitochondria or lost
them due to evolution.
Plantae: are normally
photosynthetic and live on both
land and water. This includes
land plants.
References
- Life: The Science of Biology (ninth edition) by Sadava, Hillis, Heller, and Berenbaum
(book, pages 560 – 587)
- Dr.janes. (2013). Lab 2: Animal Diversity 1. (Studyblue Inc.) Retrieved October 21,
2013, from Biology 101: http://www.studyblue.com/notes/note/n/lab-2-animaldiversity-i/deck/2701026
- College, O. (n.d.). Groups of Protists. Retrieved October 21, 2013, from Connextions:
http://cnx.org/content/m44617/latest/?collection=col11448/latest
- LaurenLewis9. (2012, March 6). BIOL102 Lab Chapter 6. Retrieved October 21, 2013,
from Quizzlet: http://quizlet.com/10531521/biol-102-lab-chapter-6-flash-cards/
- Choanoflagellates. (n.d.). Retrieved October 21, 2013, from WikiPremed:
http://www.wikipremed.com/image.php?img=040506_68zzzz328350_Cronoflagela
do2_68.jpg&image_id=328350
- Freeman, S. (n.d.). Biological Science. University Washington .