Transcript Classification Systems Change as Scientists Learn More

Classification Systems Change
as Scientists Learn More
• Taxonomy Changes as Scientists make
Discoveries.
– 3 Domains & 6 Kingdoms
• The 2 most Familiar Kingdoms are Plants &
Animals
• Other Organisms make up 4 More Kingdoms
– Mushrooms & Molds (which Linnaeus put as plants)
are now classified as FUNGI
– Other kingdoms are PROTISTA, ARCHAEA &
BACTERIA
• Species & Environment Changes
– Scientist estimate there are millions or tens of millions
of undiscovered species. Species may change
somewhat as their environment changes over time.
3 DOMAINS
• Microscopes have let scientists observe 3 different
types of cells; so they have arranged the 6 kingdoms
into 3 groups (DOMAINS) based on this.
• Eukarya includes protists, fungi, plants & animals
(all have a nucleus, so are eukaryotes)
• Bacteria and Archaea have no nucleus
(PROKARYOTE cells). Archaea have a unique
chemistry and can survive extreme environments.
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6Kingdom
KINGDOMS
Plantae: plants;
trees, grass & moss
Kingdom Animalia: animals;
lions & bears to bugs &
multicellular microbes.
Kingdom Protista: mostly
unicellular organisms with
nucleus
Kingdom Fungi: mushrooms,
molds, & yeasts
Kingdom Archaea: similar to
bacteria, but very unique cell
structure
Kingdom Bacteria: unicellur
organisms with no nucleus
This system may change as
we learn more
Plantae & Animalia Kingdoms
• About 250,000 plant
species live on Earth.
(tiny mosses to giant
sequoia trees)
• Oldest plant = bristelcone
pine -over 4,000 years old
• All plants are
multicellular eukaryotes
(nucleus). All can make
sugar from Sun’s Energy,
can’t move around except
by growing upward &
toward light.
• Plant cells differ from
animal cells by having
tough walls outside of
cell membrane.
• Scientists already named a
million species of animals.
More than 90% are insects, but
also whales, sharks, humans,
bears, dogs, fish.
• All animals get energy by
eating other organisms or by
eating food made by other
organisms.
• Have ability to move around
for at least part of life.
• Most animals have mouths &
nervous system.
• Are eukaryotes (like plants) but
have no cell walls.
PROTISTA
• Includes wide variety of
organisms (many scientists
think this should be split into
more kingdoms)
• Most are unicellular, some are
multicellular but too simple to
be fungi/animal or plants.
• All have large, complex cells
with nucleus (eukaryote); some
eat other organisms, some get
energy from sun (like plants);
no specialized cells or structures
• Many live in pond/sea water;
many microscopic, but seaweed
is a very large protist (may
grow hundreds of feet/year)
FUNGI
• One group of fungus, YEAST, lets bread rise. Another that
people eat are MUSHROOMS. These grow in thin threads
underground & only the small cap breaks above the ground.
• Usually 3 groups: mushroom, yeast, & molds. Fungi take in
nutrients from their surroundings instead of eating or using
sunlight.
• Stay rooted in 1 place (like plants), most have cell walls too.
• Many act as decomposers (break down dead/decaying
material into simpler parts that can be absorbed or recycled
by other organisms.
ARCHAEA
• In mid-’90’s a scientist studied
genes of some bacteria and
found some had very different
genes. These bacteria were
called archaea, and are now
known to be so different, they
are in their own kingdom &
domain.
• Archaea have no nucleus &
live in many environments
(like bacteria) but cell
structure is different than
bacteria.
• Some live in very extreme
environments (boiling mud
near gysers, hot vents on ocean
floor, salty ponds, & deep
BACTERIA
• Bacteria live nearly
everywhere on Earth. Some
cause human disease & spoil
food, but most are helpful
members of biological
community.
• All are unicellular. Small,
simple cells without a
nucleus(prokaryote).
• Most have cell wall, but
different from plant type.
• Reproduce by dividing in 2
(binary fission/mitosis), and
can make many new
generations in very short time
period.