Download The First Four Kingdoms

The First Four Kingdoms
Kingdoms Archaebacteria and Eubacteria
THE LIFE OF A PROKARYOTE
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Prokaryotes are single-celled organisms. They are the smallest, simplest organisms.
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The group includes:
o Archaebacteria are found in anaerobic and extreme conditions (high [salt], high temperature, and low pH), similar
to what are believed to be the conditions on the early Earth.
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Earth’s early atmosphere did not contain oxygen, therefore the earliest organisms were anaerobic.
o Eubacteria includes the traditional bacteria and is the larger of the two.
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They are found in nearly every habitat studied, including some that no other organism is able to withstand.
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Bacteria have a cell wall and cell membrane, but no membrane-bound organelles such as a nucleus, mitochondria,
chloroplasts, Golgi apparatus, or ER. Some are covered by a layer of “slime” called a capsule.
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They show three basic shapes
o Cocci – spherical
o Bacilli - rod-shaped
o Spirilla – spiral
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Some bacteria are able to move using special cell structures called cilia and flagella.
o Hair-like cilia (singular, cilium) and tail-like flagella (singular, flagellum) are projections from the cell.
o By repetitive beating (like a bending motion), they cause the cell to move. Think of oars in a boat. Flagella can
propel the cell by waving back and forth.
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If a cell is fixed in place, they can also cause water to move across the surface.
RESPIRATION

Obligate aerobes must have oxygen.
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Obligate anaerobes can not survive in the presence of oxygen.
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Facultative anaerobes will use oxygen if it is present but do not need it.
NUTRITION
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Most are heterotrophic…
o Some are parasites which live off a living host.
o Some are decomposers, feeding on dead organisms and waste.
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Some are autotrophic…
o Either use chemicals as a source of energy (chemoautotrophs) or are photosynthetic (photoautotrophs).
REPRODUCTION
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Prokaryotes have a single circular chromosome attached to the inside of the plasma membrane.
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Asexual reproduction
o Prokaryotes reproduce by simply splitting in two in a process called binary fission.
o The DNA is copied and the cell divides into two identical cells.
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Sexual reproduction
o Sexual reproduction combines genes from two different individuals and increases variation. Prokaryotes do not
technically reproduce sexually but can mix genes with one another.
o Conjugation - Two cells join briefly and one cell donates some DNA (called a plasmid) to the other one.
Sometimes part of the cell’s chromosome is donated as well.
o Transformation - Bacteria can also pick up pieces of DNA from the environment.
o Transduction - sometimes viruses transfer pieces of DNA from one cell to another.
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Endospores
o Some bacteria form endospores when environmental conditions become unfavorable.
o Endospores are DNA and a small amount of cytoplasm enclosed in a tough cell wall. They are resistant to
extremes in temperature, drying, and harsh chemicals.
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Mutation is a large source of genetic diversity in bacteria.
Kingdom Protista
THE LIFE OF A PROTIST
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Kingdom Protista consists of organisms that don’t seem to fit anywhere else.
o They are simply eukaryotes that are not fungi, plants, or animals.
o They are so diverse that some argue they should be split into additional kingdoms.

Protists are some of the earliest organisms on Earth. The first eukaryotic cells are thought to have been protists. They gave
rise to fungi, plants, and animals.
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Most protists are small, single-celled organisms that are not necessarily related to one another.
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Protists are eukaryotes that lack the specialized features of fungi, plants, and animals, although they do have membranebound organelles.
The three large taxonomic groups of protists, based on how they obtain nutrition, show huge diversity:
o Plant-like
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Mostly non-motile; photosynthetic.
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Often called algae or seaweeds.
o Animal-like protists
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All motile heterotrophs.
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Includes sarcodines (e.g., Amoeba proteus), ciliates (e.g., Paramecium caudatum), and flagellates
(e.g., Euglena gracilis.).
o Fungus-like
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These heterotrophs obtain nutrition by extracellular digestion.
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These grow in dark, shady habitats and are called slime molds.
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Most are colorful and can be found underneath rotting logs or leaves.
RESPIRATION
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Protists are almost exclusively aerobic.
NUTRITION
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Various feeding strategies:
o Some have chloroplasts and manufacture food like plants.
o Others ingest food like animals.
o Others absorb food like fungi.
REPRODUCTION
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All are capable of asexual reproduction but some reproduce sexually as well.
KINGDOM FUNGI
THE LIFE OF A FUNGUS
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Although originally classified as plants because they share some characteristics, fungi have several characteristics that
make them different:
o They lack chlorophyll, therefore they are not photosynthetic.
o The cell wall is made of chitin rather than cellulose.
o Fungi are heterotrophs and absorb food after the secretion of enzymes and extracellular digestion. Plants are
photosynthetic.
o Fungi reproduce by spores rather than seeds.
o Fungi are composed of filaments called hyphae. Hyphae may be branched. A dense mass of hyphae is called a
mycelium.
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Hyphae may contain internal crosswalls that divide the hyphae into separate cells. The crosswalls of
many species have pores, allowing cytoplasm to flow freely from one cell to the next. Cytoplasmic
movement within the hyphae provides a means to transport of materials.
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There are many uses for fungi:
o Many are harmful and cause decay, rot and spoilage.
o Some cause serious plant and animal diseases.
o Many are beneficial
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Yeasts are used in the manufacture of bread, wine and beer.
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Production of penicillin.
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Many mushrooms are eaten as food.
NUTRITION
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Fungi are major decomposers in every ecosystem. They break down matter into simple nutrients that can be used by other
organisms.
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All are heterotrophic. Fungi excrete enzymes into their environment to digest food. They then absorb the nutrients.
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Most species of fungi decompose dead matter. Many are parasitic and obtain nutrients from living organisms.
REPRODUCTION
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Most fungi reproduce sexually although there are a few examples of those that reproduce asexually.
o Yeast are a notable exception as they show mostly asexual reproduction.
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The hyphae of two individuals meet and fuse. The resulting fungus then has DNA from each of the two partners.
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The above ground structure that we call a mushroom is actually the reproductive structure. Spores produced in the
mushroom are dispersed and grow into new individuals. Spores are non-motile, unlike the gametes of plants and animals.
o Spores are dispersed over great distances by wind, insects, and animals.
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