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TRANSCRIPT
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Biological Diversity, Bacteria,and Archaea
Psychedelic Frogfish Indian Pipe Plant Spirillum
Stone Plant Amoeba Devil’s Finger Fungus
Life on Earth
• Throughout the text they refer to “life on Earth”.
• I will use “life” as “life on Earth” for simplicity, but there may be life elsewhere!! Very exciting!
The Extent of Earth’s Biodiversity Is Unknown
• The Earth’s biodiversity includes all living things
• Humans have only identified 1.5 million of an estimated 3 to 100 million species
– W2L: Why? What do you think are some the characteristics of these unidentified organisms?
The Linnaean System of Biological Classification
Domain……………………….Did
Kingdom……………………..King
Phylum……………………….Philip
Class……………..…………..Come
Order………………………….Over
Family………………………...For
Genus…………………………Great
Species……………………….Soup?
Linnaean Taxonomy
• Taxonomy is the part of biology that names organism
• As the name gets closer to the species the group gets more narrow
The basis of the Domain system is based off of rRNAsequence information
Taxonomy
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All Life can be Sorted into Three Domains
• Domain Bacteria
– single‐celled organisms, some cause disease
• Domain Archaea
– “ancient” bacteria
– single‐celled organisms that tend to live in extremely harsh environments
• Domain Eukarya
– includes plants, animals, fungi, and protista
Prokaryotes
Eukaryotes
Cell Type
Prokaryotes verses Eukaryotes
• Prokaryotes do not have a nucleus, Eukaryotes do
• The nucleus is a membrane bound organelle that surrounds the DNA of the cell
A Common Origin Explains the
Unity of Life on Earth
• Scientists think all life descended, through evolution from a common ancestor– shares a set of basic characteristics
– W2L: We talked about these characteristics, what are some of them?
A Common Origin Explains the
Unity of Life on Earth
• All life is categorized in one of three domains: Archaea, Bacteria, and Eukarya
• A branching diagram called an evolutionary tree shows the relationships among groups of organisms
Evolutionary Divergence: Diversity of Life
• A node on an evolutionary tree represents the most recent common ancestor of two organisms
Evolutionary Divergence: Diversity of Life
• A clade is an ancestor and all the descendants that come from it.
• Below the red and blue boxes represent clades
• If the green box was big enough to incorporate the branches in the blue box too that would be a clade
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Evolutionary Divergence: Diversity of Life
• Shared derived traits are evolutionary novelties that are used to help determine relatedness among species
Sorting Organisms Taxonomic Groups
• To place organisms of the six kingdoms of life on an evolutionary tree scientists use:
–DNA
–Shared Traits
W2L: Why do you think we use these to classify organisms? Which is more reliable?
W2L: Do Eugleoids and Diplomonads have more similar or more different DNA than Eugleoids and green algea?How do you know?
Bacteria appeared approximately 3.5 billion years ago
Bacteria and Archaea
• Tiny, Successful, and Abundant
• Bacteria are single‐celled organisms
• The majority of bacteria are not harmful to humans
• Archaeans are single‐celled organisms and are not believed to cause disease
Archaeans
• Extremophiles are archaeans that thrive in extreme environments such as geysers and acidic waters
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Kingdom Archaea bacteria
Halophilic bacteria
Thermophilic bacteria
Kingdom Archaea bacteria
•Astrobiologists think that if life is found on other planets it will be bacteria-like
•Using chemical energy for their life needs
For energy these bacteria use sulfur for energy rather than sugars!! SO cool!!!!!
•Record held by a type of thermophile known as a hyperthermophile: 235°F.
Prokaryotes Represent Biological Success
• Bacteria are the most widespread organisms and can reproduce quickly through a process of asexual reproduction called binary fission
Prokaryotes Occupy a Great Diversity of Habitats
• Bacteria can be found in some of the most extreme environments on Earth…even without oxygen!
• Aerobic bacteria: can use oxygen to survive
• Anaerobic bacteria: do not require oxygen to survive
Prokaryote Structures
• Most prokaryotes have a cell wall that surrounds a plasma membrane
Cell wall
Plasmamembrane
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Prokaryote Structures
• Some prokaryotes have a capsule that helps them evade an organism’s defense system
Prokaryote Structures• Pilli and flagella are structures that allow bacteria to thrive in certain environments
Pilli
Flagella
Prokaryotes are Mainly Single‐Celled, But Some Show Social Behaviors
• Although they are single‐celled organisms, some prokaryotes exhibit multicellular organization
Biofilm
E coli cell disrupted to release its DNA molecule.
Prokaryote DNA
• Have less DNA than Eukaryotes
Prokaryotes Pick‐up DNA
• Some prokaryotes can use bits of DNA from their environment
Ex. Antibiotic resistance
Prokaryotes Reproduce Asexually
• Prokaryotes can receive DNA from other species and incorporate it into their own DNA
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Prokaryotes: Metabolic Diversity
• W2L: What is metabolism? Remember it was one of our characteristics of life.
Metabolism
• Metabolism is the building up and breaking down of molecules in an organism.
• Two things are needed:
– Energy
– Building materials
Metabolism: Energy
• The energy to make molecules comes from one of two places:
– From the sun: Photo‐
– Or from chemicals: Chemo‐
Metabolism: Building Blocks
• The main building block for organisms is carbon, where does this carbon come from?
• Carbon can come from inorganic substances such as CO2 from the environment.
– Autotrophs or producers
• Carbon can come from organic substances such as carbohydrates from food.
– Heterotrophs or consumers
Metabolism: Building BlocksEnergy Source
Photo‐Energy from Sun
Chemo‐Energy from chemicals
Carbon Source
Auto‐Carbon from inorganic molecules
Photoautotrophs Chemoautotrophs
Hetero‐Carbon from organic molecules
Photoheterotrophs Chemoheterotrophs
Prokaryotes: Metabolic Diversity
• Photoautotrophs
– Use light as energy and inorganic molecules as carbon source (ex CO2, like plants). Producers
• Photoheterotrophs
– Use light as energy and organic molecules as carbon source. (ex. green non‐sulfur bacteria) Consumers
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Prokaryotes: Metabolic Diversity• Chemoautotrophs
– Use chemical energy and inorganic molecules as a carbon source. Some of the chemical energy that can be used is from : iron ore, hydrogen, sulfur, etc…(Ex. Chemolithotrophs). Producers
• Chemoheterotrophs
– Use chemical energy and organic molecules as a carbon source (animals) . Consumers
Producers/Autotrophs: Produce Organic Molecules
Consumers/Heterotrophs: Consume Organic Molecules
Prokaryotes Changed the World with Oxygen‐Producing Photosynthesis
• Prokaryotic photosynthesis changed the atmospheric composition of Earth by increasing the level of available oxygen
Prokaryotes Changed the World with Oxygen‐Producing Photosynthesis
• The increased oxygen levels in the atmosphere allowed for larger eukaryotic cells that require more energy to thrive
Prokaryotes Play Important Roles in the Biosphere and in Human Society
• Prokaryotes are important members of all ecosystems:– Cyanobacteria are the basis of the food chain in aquatic ecosystems.
• W2L: What would happen without this?
– Decomposers break down dead organisms and recycle the nutrients back into the environment.
• W2L: What would happen without this?
– Plants benefit from bacteria that use atmospheric nitrogen and convert it into ammonia through nitrogen fixation.
• W2L: What would happen without this?
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Prokaryotes Play Important Roles in the Biosphere and in Human Society
• Humans benefit from prokaryotes
– Prokaryotes produce antibiotics as a by‐product of metabolism
– Fermentation occurs when certain bacteria lack oxygen to carry out metabolism. Fermentation produces such things as alcohol, cheese, and butter
– Bioremediation is the use of
organisms to clean up
environmental pollution
All of Us Together
• The Human Microbiome Project is an attempt to identify and catalog the proposed several thousand species of microbes inhabiting the human body
• All of us live in harmony with many kinds of bacteria. – W2L: What are some examples?
Some Bacteria Cause Disease
• Pathogens: organisms that cause disease
• Most pathogens are host specific. What does this mean?
Some Bacteria Cause Disease
• Certain pathogens can secrete exotoxins that damage surrounding tissue, while others produce endotoxins, which triggers illness in the host organism
Some Bacteria Cause Disease
• Antibiotics are secreted by some microorganisms to kill or slow the growth of another microorganism—great source!!
• Overuse of antibiotics can lead to selection for antibiotic resistance
• Antibiotics are ineffective against viruses
Viruses Lack Cellular Organization
• Although viruses contain DNA and can reproduce, and evolve, they lack the structures within cells that are necessary for cellular life
• Viruses are know
to attack
organisms in every
kingdom of life