BLG 144 Lecture Notes - Lecture 13: Amoebiasis, Nuclear Membrane, Paraphyly
27 Apr 2018
School
Department
Course
Professor
CHAPTER 29 - PROTISTS
- Paraphyletic grouping that includes all eukaryotes except the land plants, fungi, and animals.
- morphological innovations occurred as protists diversified:
1. Nuclear envelope
2. Multicellularity
3. Array of structures that function in support and protection
4. Mitochondrion and chloroplast arose by endosymbiosis
- Vary in how they get their food
- Many species are photosynthetic, while others obtain carbon compounds by ingesting foods or
parasitizing other organism
- Vary on how they reproduce. Can reproduce sexually or asexually
- Eukaryotes range from single celled organisms the size of bacteria to sequoia trees and blue
whales
- Protists refer to a paraphyletic group – represent some, but not all of the descendants of a
single common ancestor
- No synapomorphies define the protists (every trait in an organism can be found in other
organisms)
- Common feature is that they live in environments surrounded by water
Why do biologists study protists? Important medically, ecologically and critical to understand evolution
of plants, fungi and animals
Impacts on Human health and welfare
- Several types can cause human disease and disease in crops :
1. Malaria – caused by a parasitic protist called plasmodium that transferred to humans
from mosquitoes
▪ Cells tpes for eah stage of the plasodiu’s life le is speialized for
infecting a specific host cell
▪ Half the world’s populatio was at risk
▪ Number of other human health problems are also caused by protists, including
amoebic dysentery and trichomoniasis
2. Harmful Algal blooms - happen when dinoflagellates (toxin producing protists) reach
high densities in an aquatic environment. Known as red tides
▪ Toxins built up in class and other shellfish can be toxic to humans
▪ Several types of poisons come from eating contaminated shellfish
Ecological importance of protists
- Represent 100% of eukaryotic species and have a low diversity, but are abundant
- Primary producers – species that produce chemical energy by photosynthesis
- Almost half the total carbon dioxide fixed on earth is made by the production of organic
molecules by protists in the oceans
- Plankton - Diatoms, green algae, and other small organisms living in near water and drift along
or swim only short distances
find more resources at oneclass.com
find more resources at oneclass.com
