Chapter 28

Protista!

•Make a wet mount slide of the “pond” water (from your very own GCM ditch) using about 2 drops of “mucky” water•Observe the protists in the water!•Draw at least 6 diagrams total of protists you observe under 10X and 40X magnifications (3 in each?)•Make your drawings as detailed as possible and label parts you think you can identify. Be sure to include the magnification under which you are observing.

•Research protists and try to classify the organisms you drew!

Survey of Protists!

Why is “Protista” no longer considered a kingdom?

Most are unicellular but can be colonial or multicellular

Protista

1.Photosynthetic, plant-like protists (algae)

2.Ingestive, animal-like protists (protozoa)

3.Absorptive, fungus-like protists

Protista

Some are motile, others are not; most have cilia or flagella at some point in their lives

Protista

Life Cycles1.Mitosis2.Sexual reproduction3.Meiosis and syngamy (formation of a zygote from 2 gametes)

Protista

Habitats – most are aquatic, including oceans, ponds, lakes, damp soil, leaf litter, etc1.Important constituents of plankton; phytoplankton (photosynthetic protists) are the bases of most marine and freshwater food webs2.Symbionts inhabiting body fluids, tissues, and cells of hosts (relationships vary from mutualistic to parasitic)3.Parasitic parasites include the malaria parasites (several species of plasmodium), Giardia lamblia (synonymous with Giardia intestinalis) which causes diarrhea, Trichomonas vaginalis (an STD), and several Trypanosoma species which cause sleeping sickness

Protista

Plasmodium

Giardia lamblia

African trypanosomiasis : symptoms in two stageshaemolymphatic phase: fever, headaches, joint pains, and itching; severe swelling of lymph nodes; Winterbottom's sign, the tell-tale swollen lymph nodes along the back of the neck, may appearIf untreated: anemia, endocrine, cardiac, and kidney dysfunctionsneurological phase: parasite invades the central nervous system; term 'sleeping sickness' comes from these symptoms: confusion, reduced coordination, disruption of the sleep cycle with bouts of fatigue punctuated with manic periods lead to daytime slumber and night-time insomniaWithout treatment, invariably fatal; progressive mental deterioration leading to coma and death; damage caused in the neurological phase is irreversible

Trypanosoma – Sleeping Sickness

The Origin and Early Diversification of Eukaryotes

Unique to Eukaryotes

Membrane-bound nucleusEndomembrane systemMitochondriaChloroplastCytoskeleton9+2 flagellaMultiple chromosomes and linear DNA assoc. with proteins

Life cycles with mitosis, meiosis, and sex

Unique to Eukaryotes

Trends Leading to Increased Complexity

Trends Leading to Increased Complexity

Trends Leading to Increased Complexity

The Endomembrane System

The Endomembrane System

Endosymbiosis

Endomembrane System and Endosymbiosis

•Leucoplast – (food cupboard) – stores starches •Chromosplast – (paint can/food coloring) – gives flowers their colors •Chloroplast – (solar panel) – converts light energy into chemical energy in the form of sugar and starch.

Plastids

•Existence of current endosymbiotic relationships•Mitochondria and chloroplast size vs. prokaryotes• Inner membranes of mito/chloro contain enzymes and transport systems like modern prokaryotes (ETC anyone?)•Mito/chloro replicate similarly to binary fission•Mito/chloro have single circular genome like prokaryotes•Mito/chloro have t-RNA, ribosomes, and other “machinery” necessary to synthesize proteins

Evidence for Endosymbiosis

Which evidence is strongest?

Which evidence is weakest?

Chimera

Cyanobacteria – ancestors of chloroplasts

Alpha Proteobacteria – ancestors of mitochondria

Eukaryotic Cell Organelle Ancestors

Protista!

•Make a wet mount slide of the “pond” water (from your very own GCM ditch) using about 2 drops of “mucky” water•Observe the protists in the water!•Draw at least 6 diagrams total of protists you observe under 10X and 40X magnifications (3 in each?)•Make your drawings as detailed as possible and label parts you think you can identify. Be sure to include the magnification under which you are observing.

Survey of Protists!