Chapter 2
Self-Quiz
Unit 1: Diversity of Life
Understanding and Organizing the Diversity of Life
Review
Working from the assumption that all
life
is descended from a
,
systematists
depict the relationships among organisms as an
tree in which related groups are clustered by virtue of
to form a lineage, and classify all organisms according to an evolutionary
.
The
traditional
classification system is the
: compare similarities in
,
, and
.
This can be difficult
and subject to change over time. Biologists increasingly use molecular data such as
.
6 kingdoms:
(Monera),
,
,
,
,
. Where do viruses belong?
6 levels below Kingdom: Phylum, Class, Order, Family, Genus,
.
Scientific name is genus and specific epithet,
e.g.
Homo sapiens
: Kingdom
, Phylum
, Class
, Order
. Family
, Genus
, Species
. What about
Rosa gallica
?
Or
Rosa setigera
?
Modern taxonomy now include many more levels.
Above kingdom
are
3 domains:
,
,
. Other finer divisions also exist (do not memorize this):
(
e.g.
Metazoa),
(
e.g.
Deuterostomes),
(
e.g.
Vertebrata),
etc.
Evolutionary taxonomy
is being replaced by
, which uses
from a universal,
to determine relationships shown on a
cladogram
. These features should show
,
distinctive traits
not shared
by
other organisms.
Shared
features
do not exhibit novel traits from a common ancestor and do not indicate relatedness.
features do not indicate relatedness because they are not derived from a
, but have
developed independently
due to
to similar habitats.
Many traditional taxonomic groups are not "real" groups according to cladistics. A "real group" consists of organisms descended from a
and includes all of its descendents. In
cladistics
such a group is called a
.
Birds
share a
common ancestor
with
. Therefore, if reptiles are to be considered a
, they must include
.
Biologists are able to identify precise evolutionary relationships through the use of
and other molecular tools.
Chapter 3
Self-Quiz
Unit 1: Diversity of Life
Major Groups of Living Organisms
Review
All
organisms
evolved from a common
. All cells belong to one of two basic types.
cells
have relatively simple structure and lack specialized internal
.
cells
contain internal organelles.
Bacteria and Archaea are prokaryotes, but remember they are not a "clade" because lack of organelles is not a
from a
.
Prokaryotes
are the most abundant organisms, and reproduce by splitting in two in a process
called
.
Major parts of a
prokaryotic cell
include
,
,
, and
circular
. An
Eukaryotic cell
contains
internal
such as
,
, and a
which contains DNA.
The kingdom
Protista
is not a "clade", and includes mostly single-celled,
organisms such as
algae.
Protista are the most diverse eukaryotic organisms. Sexual reproduction first appeared in the kingdom
and requires
.
The kingdom
Plantae
contains
, eukaryotic organisms most of which are capable of producing food in the form of
via
. Thus
plants
are
, also known as
, in the food web. Plant photosynthesis also produces
that enables
aerobic life.
Two important innovations in the
Plantae
are specialized cells organized into
tissues
such as the
system
and the
seed,
which provides the growing
embryo
with nutrients and protection.
The kingdom
Fungi
is made up of eukaryotes that are mostly
, but can also be
or
in the
food web.
The
main body
is a
made of tissues called
which are usually hidden and can
grow
to be
very large.
Fungi
digest their food
, and have cell walls made of
.
Lichens
are a
and unicellular
living together as a single organism.
The kingdom
Animalia
consists exclusively of multicellular eukaryotes that are usually motile and ingest their food; they are mostly
in the food web. Most animals have specialized
,
, and
.
Acoelomates
have no
.
Porifera
are
without tissues, and can be reassembled when passed through a sieve.
Cnidaria
include
,
, and
. They possess specialized cells organized into
that allow them to move their tentacles and sometimes swim.
Platyhelminthes,
or
exhibit
bilateral symmetry
and possess
and
including simple nervous, reproductive, and digestive/excretory systems.
Tapeworms
and
flukes
are
.
Coelomates
possess a
. In
Protostomes
the first opening of the
blastula
develops into the mouth.
Annelida
such as earthworms and leeches have
bodies
capable of complex movements.
Arthropoda,
such as
insects, spiders, and lobsters,
have
legs and are protected by an
made of chitin. They are the
most diverse
organisms on earth.
In
Deuterostomes
the first opening of the
blastula
develops into the anus. Vertebrates are a subphylum of
Chordata
and possess a hard
Viruses
are difficult to classify. They may have evolved from different organisms. Many organisms show cross-
kingdom
relationships.
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Feb 23, 2006
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