Transcript The Diversity of Life

How do we classify living organisms?
 Taxonomy is the study and practice of classifying
living organisms.
 Modern taxonomy uses the three domain system.
 Domain Archaea: Unicellular and live in harsh
environments; no nuclei
 Domain Bacteria: Unicellular and ubiquitous; no
nuclei
 Domain Eukarya: Conatains unicellular and
multicellular organisms, all of which have a nucleus
 Organisms are classified by first being placed in one of
those domains, and then into increasingly narrow
groups, based on DNA similarities.
 Taxonomic ranks, order of most to least inclusive:
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Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
 Domain Archaea
contains unicellular
and prokaryotic
organisms.
 Unicellular: made up
of only one cell
 Prokaryotic: contains
no nucleus
 Archaea reproduce via
fission, and they often
live in harsh
environments.
 Domain Bacteria
contains unicellular
and prokaryotic
organisms.
 Bacteria reproduce via
fission, and they are very
common.
 They are required to
support life on Earth.
 Domain Eukarya
contains both
unicellular and
multicellular
organisms, as long as
they are eukaryotic.
 Multicellular: made up
of more than one cell
 Eukaryotic: contains a
nucleus
 Eukarya reproduce via
several asexual and
sexual reproductive
methods, depending on
the organism.
 Eukarya are further
divided into four
kingdoms:
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Protista
Fungi
Plantae
Animalia
 Protists include a
diverse collection of
unicellular and
multicellular organisms.
 Most, however, are
unicellular.
 Individual protist species
can function as animals,
plants or fungi.
 Examples: amoebae,
diatoms, some plankton
 Fungi include organisms
with a nucleus and cell
walls. Fungi are capable
of absorbing nutrients
from decaying
organisms.
 They have a vital role in
our biosphere as
decomposers, breaking
dead organisms down to
recycle matter.
 Some fungi have a
parasitic relationship
with other organisms,
such as athlete’s foot.
 Examples: Mushrooms,
yeast, mold, including
slime molds
Which domain is associated with unicellular
organisms that live in extreme environments?
2. True or false: Eukarya only reproduce sexually.
3. True or false: All eukarya have a nucleus.
4. Why are fungi so critical to our ecosystems?
1.
 Plants are multicellular
organisms with cell walls
and chloroplasts.
 Chloroplasts are
specialized structures
needed for
photosynthesis.
 Photosynthesis
generates glucose and
oxygen gas from carbon
dioxide and water.
 Plants have root systems,
to draw water and
nutrients from the soil.
 These root systems are
adapted to local
ecosystems.
 Plants also have leaves,
which are the specialized
structures that collect
light and gases.
 The leaves and roots are
usually connected with a
vascular system.
Essentially, these are
vessels that transport
water, minerals, and
glucose.
 Vascular tissue has very
thick cell walls, which
support the plant.
 Some plants, such as
mosses, do NOT have
vascular systems.
 These plants must collect
water from the
environment, so they live
in damp ecosystems.
 Plants are further divided
into gymnosperms and
angiosperms.
 Gymnosperms are
evergreens; woody trees
with needle-like leaves
and cones (which
contain the tree’s seeds).
 Gymnosperms do NOT
produce fruit; instead,
they produce cones
which open up and
release seeds.
 Gymnosperms can live in
drier environments than
other plants, as they
conserve water through
their cones and needles.
 Gymnosperms are the
primary source for our
lumber and paper.
 Examples: pines, firs,
hemlocks, cypresses,
spruces, yews, junipers
 Angiosperms are land-
based flowering plants.
 All angiosperms produce
fruits, which contain the
plant’s seeds.
 Many flowers require the
assistance of animals to
scatter seeds and for
pollination.
 Angiosperms often adapt
themselves to enable
pollination and
reproduction.
 For instance, grass seeds
are barbed, to latch on
to other organisms.
 Fruit can be eaten, and
the seeds scattered.
 Large and colorful
flowers attract potential
pollinators.
 Angiosperms are
important sources of
food, such as fruit, wheat
and beans. Also, many
angiosperms provide us
with fibers and lumber.
 Examples: grasses, oak,
palm, ivy, cactus, myrtle,
peppers, cabbage,
parsley, all flowers, beanproducing plants
_______ are plant structures designed to collect
sunlight and gasses.
2. _______ are plant structures designed to absorb
water and nutrients from the soil.
3. True or false: All plants have vascular tissues.
4. Identify whether the statement describes
gymnosperms or angiosperms:
1.
Produce flowers and fruit
b. Woody and needle-like leaves
c. Cones, for containing seeds
a.
 Animals are consumers –
they cannot produce
their own food. They
must consume other
organisms for nutrients.
 Animals cells do not have
cell walls. This means
that animals have soft
and flexible bodies.
 Animals may or may not
have a skeletal structure.
 Animals without a
backbone are called
invertebrates.
 Animals with a backbone
are called vertebrates.
 Invertebrates are very
diverse.
 Some invertebrates
anchor themselves to
hard surfaces in the
ocean. They filter food
from the water, and are
called filter feeders.
 Examples: corals,
mollusks, barnacles,
several worms
 Other invertebrates
inhabit the ocean as
active consumers,
whether as omnivores,
hunters or scavengers.
 Examples: squid,
lobsters, crab, octopi.
 Insects are the largest
sub-group of
invertebrates, by far.
 Insects have a waterproof
exoskeleton, which holds
in moisture. They move
and reproduce quickly.
 Insects are often key pollinators for various
ecosystems. Indeed, many plants have coevolved along
with insects, and both organisms need each other to
survive.
 Insects are also used to control pests that might harm
other crops. Ladybugs are a good example.
 However, insects can also act as vectors for disease, and
can cause damage by eating crops.
 Examples: butterflies, moths, beetles, flies,
mosquitoes, termites, mantises, bees,wasps,
grasshoppers, ants
 Vertebrates are also very
diverse.
 The first vertebrates were
fish, as life evolved from
the oceans.
 Today, many vertebrates
live on land.
 Animals include several subgroups:
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2.
3.
4.
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Fish, which live entirely in aquatic environments. Many
have gills, to collect oxygen.
Amphibians, which are partially terrestrial and partially
aquatic. Virtually all return to water to nest.
Reptiles, the first true terrestrial vertebrates. They lay
virtually waterproof eggs, and like fish and amphibians,
are cold-blooded.
Birds are warm-blooded vertebrates with feathers. Their
eggs have hard shells.
Mammals are warm-blooded vertebrates with fur, and are
capable of producing milk.
1.
Determine the kingdom of each animal from the
description.
Thick cell walls and chloroplasts
b. Mainly unicellular, microscopic
c. Includes invertebrates and vertebrates; no cell wall
d. Cell wall, but they absorb nutrients from dead
organisms or other organisms; decomposers.
a.
_________ are invertebrates, and are key pollinators
in nature.
3. _________ were the first vertebrates to exist.
2.