How old is Earth?
4.5 billion years
How long have microorganisms inhabited the Earth?
3.8 billion years
On what basis are organisms placed into the various groups in a classification scheme?
shared evolutionary history
What are the three domains that classify all living things?
archaea, bacteria, eukaryotes
Which of the three domains contain microorganisms?
Which of the three domains are prokaryotic?
On what basis was it determined that bacteria and archaea should be classified into different domains?
rRNA structural differences
What characteristics are shared by bacteria and archaea?
All are prokaryotic, unicellular, and reproduce via binary fission.
What characteristics differ between bacteria and archaea?
bacterial cell walls contain peptidoglycan, other structural and chemical differences, many archea are are extremophiles
Do fungi represent an evolutionary grouping? Explain.
yes, they are a kingdom, which is a grouping based upon shared evolutionary ancestry.
List the general features common to all fungi.
rigid cell walls (generally composed of chitin), chemoheterotrophic (obtain carbon and energy from other organisms), eukaryotic.
Are fungi unicellular or multicellular? Explain.
they are dimorphic, meaning they are both unicellular (ex: yeast) and multicellular members (ex: molds and mushrooms)
What is a dimorphic fungus?
meaning they are both unicellular (ex: yeast) and multicellular members (ex: molds and mushrooms)
How do fungi get their energy?
organisms that get their energy from other dead organisms
organisms that get their energy from other live organisms
How are fungi important in the environment?
saprobes decompose dead organisms, allowing other organisms to access their nutrients. fungi both produce (ex: fermentation) and destroy food supplies (ex: spoilage) (from a human point of view).
How are fungi important to humans?
they spoil food and are responsible for some disease, they also produce fermented food products.
a beneficial association between fungi and plant roots, formed in roughly 90% of vascular plants, which increases the plants ability to obtain nutrients from soil in return for carbohydrates to the fungi.
a beneficial association between fungi and a photosynthetic algae or bacterium, where the fungi provides nutrients, water, and protection from desiccation; while the algae provides carbohydrates to the fungi.
How are fungi similar to bacteria?
both have cell walls and reproduce via binary fission
How do fungi differ from bacteria?
cell wall made of peptidoglycan in bacteria, chitin in fungi. fungi are dimorphic while bacteria are unicellular, fungi are eukaryotic while bacteria are prokaryotes.
Do algae represent an evolutionary grouping? Explain.
no, they are classified in terms of being eukaryotic organisms that perform oxygenic photosynthesis. no shared evolutionary ancestry.
List the general features common to all algae.
rigid cell walls, oxygenic photosynthesis, eukaryotic.
Are algae unicellular or multicellular? Explain.
algae exist in unicellular, multicellular, or communal forms (groups of unicellular organisms)
How do most protozoa get their energy?
most are heterotrophic, some are photosynthetic autotrophs.
Do protozoa represent an evolutionary grouping? Explain.
no, they represent a diverse grouping of unicellular, mostly mobile eukaryotes, not a monophyletic grouping.
List the general features common to all protozoa.
protozoa are usually single-celled and heterotrophic eukaryotes containing non-filamentous structures that belong to any of the major lineages of protists. They are restricted to moist or aquatic habitats (i.e., they are obligate aquatic organisms). Many protozoan species are symbionts, some are parasites, and some are predators of faeces bacteria and algae. There are an estimated 30,000 protozoan species.
Are protozoa unicellular or multicellular?
How do most protozoa get their energy?
most are hetertrophic, some are photosynthetic.