Chapter 9 Flashcards
Taxonomy
the system we use to name and classify all organisms (living and extinct)
Taxonomy is based on the system developed by
Carl Linnaeus (Carl von Linne) developed in 18th century
System of binomial nomenclature
because every organism has a two part name i.e homo sapiens, panthera leo (lion)
Linnaeus classified every organism in a
hierarchy, taxa, or levels of organization
The taxa are:
*king phillip
domain, kingdom, phylum, class, order, family, genus, and species
Kingdom
- the most general
- consists of the most varied organisms
Species
- the most specific
- consists of organisms that are the most similar
1950s /60s
all organisms were placed into only 3 kingdoms
60s - 1990
scientists expanded the system to 5 kingdoms : Monera (no longer used), Protists, Fungi, Plantae, and Animalia
1990
some scientists added a 6th kingdom, Archaebacteria which included extremophiles (microorganisms that live in extreme environments) and that seemed so different from bacteria that they had to placed into a separate kingdom
Today most scientists use the
3 domain system
based on DNA analysis
The 3 domain system more accurately
reflects evolutionary history and the relationships among organisms
All life is organized into 3 domains
Bacteria, Archaea, and Eukarya
superkingdoms
eukaryota, prokaryota
separate by cell structure
-3 domain system is now favored
Why is monera not used anymore?
because prokaryotes are spread across two different domains , Archaea and Bacteria
Why did scientists switch from the superkingdoms to the 3 domain kingdom?
because Archaea have so little in common with bacteria that they must have their own group
Why did archaebacteria have to be changed to archaea?
because the Archaea are not bacteria
Bacteria:
What are bacteria?
All are single-celled prokaryotes w/ no internal membranes (no nucleus, mitochondria, or chloroplasts)
Some bacteria are _____,some are ______.
anaerobes, aerobes
Bacteria are decomposers that
recycle dead organic matter
Bacteria play a vital role in
genetic engineering (bacteria from the human intestine, escherichia coli, are used to manufacture human insulin)
Some bacteria are _____(blue-green algae); others are _________.
autotrophic
heterotrophic
Do bacteria have introns?
bacteria don’t have introns (noncoding regions within DNA)
Bacteria have a thick,
rigid cell wall
Member species correspond roughly to the old grouping _______ and include:
Eubacteria
- blue-green algae
- bacteria like E.coli that live in the human intestine
- those that cause disease like Clostridium botulinum and Streptococcus
- those necessary in the nitrogen cycle, like nitrogen-fixing bacteria
Archaea:
unicellular and prokaryotic
-no internal membranes such as a nucleus
Archaea include
extremophiles, microorganisms that live in extreme environments
Extremophiles in archaea include
- methanogens
- halophiles
- thermophiles
Methanogens
obtain energy by producing methane from hydrogen
Halophiles
thrive in environments with high salt concentrations like Utah’s Great Salt Lake
Thermophiles
thrive in high temps, like hot springs in Yellowstone, or deep-sea hydrothermal vents
Are introns present in archaea?
introns are present in some genes
All animals belong in the domain
Eukarya
In eukarya
All organisms have a nucleus and internal organelles
Eukarya includes the
4 remaining kingdoms
4 kingdoms in Eukarya are
protista
fungi
plantae
animals
Protista includes organisms that do not fit into the fungi or plant kingdoms such as
seaweeds and slime molds
Protista include
the widest variety of organisms but all are eukaryotes
Most protista are
single-celled, but many are primitive multi celled organisms
What do protista include?
- Includes heterotrophs (such as amoeba and paramecium)
- autotrophs (euglenas which have a red eyespot to locate light and chlorophyll to carry out photosynthesis)
How do protists move?
by various means
amoeba use psuedopods
paramecium use cilia
euglena use a flagellum
Some protists (i.e. paramecium, algae) sometimes carry out
conjugation, a primitive form of sexual reproduction where individuals exchange genetic material
Some protists also cause
serious diseases like amoebic dysentery and malaria
Fungi
All are heterotrophic eukaryotes
Can be unicellular or multicellular
What role do fungi play in ecology?
decomposers
Digestion in Fungi
Carry out extracellular digestion by secreting hydrolytic enzymes outside the body
[fungi] After digestion ,
the building blocks of the nutrients are absorbed into the body of the fungus by diffusion
Fungi are saprobes,
organisms that obtain food from decaying organic matter. As such they recycle nutrients in an ecosystem.
What are cell walls in fungi composed of?
chitin, not cellulose
Certain fungi combine with algae in a
symbiotic relationship forming various lichens which are photosynthetic.
Lichens can survive
harsh, cold environments and even live on bare rock.
Lichens are often the pioneer organisms,
the 1st to colonize a barren environment in an ecological succession
How do fungi reproduce?
Reproduce asexually by budding (yeast), spore formation (bread mold), or fragmentation whereby single parent breaks into parts that regenerate into whole new individuals
-they also reproduce sexually
Examples of fungi:
- yeast
- mold
- mushrooms
- fungus that causes athlete’s foot
Plantae
All are multicellular, nonmotile, autotrophic eukaryotes
Plantae cell walls are made of
cellulose
Plants carry out photosynthesis using
chlorophyll a and b
Plants store their carbohydrates
as starch
How do plants reproduce?
Reproduce sexually by alternating between gametohpyte (n) and sporophyte (2n) generations (known as alternation of generations)
Some plants have vascular tissue (_______), and some have no vascular tissue (________)
tracheophytes
bryophytes
Examples of plantae
- mosses
- ferns
- cone-bearing/flowering plants
Animalia
- All are heterotrophic, multicellular eukaryotes
- Most are motile, can move on their own
How do most animals reproduce?
Most animals reproduce sexually with a dominant diploid (2n) stage
Animalia: In most species, a small flagellated sperm fertilized
a larger, nonmotile egg
What is traditional way of classifying animals?
primarily based on anatomical features (homologous structures) and embryonic development
Animalia are grouped in ____ phyla but we commonly discuss _____
35
9
What are the 9 commonly discussed phyla?
porifera, platyhelminthes, annelids, arthropods, cnidarians, chordates, nematodes, echinoderms, mollusks
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