Transcript Tubeworms have no mouth, eyes, or stomach (“gut”). Their survival

Ch.26/27
• I. History of life
•
A. Earth formed about 4.5 billion years
ago
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B. Life began a few 1,000,000 years later
• 1. Metabolic activity found in 3.5 billion year old rocks
• 2. 3.5 billion year old fossils have been found
• C. Major happenings
• 1. RNA sequence data
shows 2 distinct groups
of prokaryotes which
split about 2 billion
years ago.
a. Archeabacteria
b. Eubacteria
• 2. 2.5 billion years
ago production of
oxygen created an
aerobic environment.
– a. More diversity
exists between
prokaryotes than all
eukaryotes
combined.
Probionts
• 3. 2.2 billion years is the oldest fossils of
eukaryotes
– a. Mitochondria and chloroplasts were probably cells
within cells. ( endosymbiosis)
– b. RNA was probably the first genetic material
• 4. Plants arose from green algae
• 5. Fungi and animals arose from
different groups of heterotrophic
organisms.
– a. Molecular evidence suggests animals are more
closely related to fungi than to plants.
– b. Oldest animal fossils are invertebrates from 700
million years ago.
• 6. Plants and fungi came on land about 475 million years ago
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There is a lot of speculation on how life first came to be and the subject is still
open to debate.
D. RNA: the first genetic material
1. Now it is DNA->RNA->protein
2. A more simple version would have been RNA-> protein
– a. RNA has been found to act like a catalyst and these are called
ribozymes.
Endosymbiosis
• II. The major lineage's of life
• A. The 5 kingdom system recognizes to
fundamentally different types of cells,
prokaryote and eukaryote.
• 1. Kingdom Monera - lumps all bacteria
together
– 2. The plant, fungi and animal kingdoms are all
multicellular organisms.
Ch.26 Domains
• a. Plants are autotrophic
• b. Fungi are heterotrophic but absorb
their food
• c. Animals are heterotrophic but ingest
and digest
• 3. The protist kingdom contains all the
single celled eukaryotes and any that
did not fit the other kingdoms.
• B. The domains
• 1. Superkingdoms _Bacteria, Archaea and
Eukarya also referred to as domains
Ch. 27
Prokaryotes
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I. The two main branches of
prokaryotes
A. Archea - means ancientthought to be most likely
the earliest cells, but
wrong.
B. Eubacteria
C. Shapes and sizes of
prokaryotes
1. spheres- cocci (go
ahead laugh now and get it out
of your system)
2. rods- bacilli
3. helices
Conjugation ch.27
• D. Reproduction
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1. binary fission
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2.Transformation-_genes taken up
from surroundings, like pGlo_
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3.Conjugation-_transfer of genes
from one prokaryote to another
4.Transduction-genes from virus
acquired by bacteria
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E. Nutrition
• 1. Photoautotrophs =Photosynthesis yields organic compounds
2. Chemoautotrophs - oxidize chemicals like, hydrogen sulfide and
ammonia instead of using light for energy (only found in
prokaryote nutrition)
• 3. Photoheterotrophs - use light and organic compounds, can not use
carbon dioxide.
• 4. Chemoheterotrophs - must consume organic molecules.
• 5. Cyanobacteria were the first to use water instead of
hydrogen sulfide
• Phylogeny
•
A. Archea
• 1. Methanogens produce methane from hydrogen gas
and carbon dioxide- oxygen is poison to them
• 2.Halophiles live in saline places.
• 3.Thermophiles like high heat
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B. Bacteria
1. Make up the majority of prokaryotes
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III. Importance of prokaryotes
• A. Decomposers- they return elements to the environment
• B. Symbiosis- relationships _between organisms
– 1. Mutualism- Rhizobium and legumes, nitrogen is fixed
for the plants to use
– 2. Commensalism- Bacteria living in the vagina keep it
basic to prevent yeast growth
C. Diseases
1. Endotoxin- proteins on the prokaryote membranes
» Exotoxin- proteins secreted by prokaryotes, ex
botulism toxin- 1 gram can kill 1 million people
• D. Research
Exotoxins
Tubeworms have no mouth, eyes, or stomach (“gut”). Their survival depends
on a symbiotic relationship with the billions of bacteria that live inside of
them. These bacteria convert the chemicals that shoot out of the
hydrothermal vents into food for the worm. This chemical- based food-making
process is referred to as chemosynthesis.
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Salmonella
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Lyme disease, or borreliosis, is an emerging infectious disease
caused by bacteria from the genus Borrelia