Transcript Classification Intro - LaPazColegio2014-2015

CLASSIFICATION
Invertebrates
ANIMALIA
Deuterostomes
(sea urchins, sea stars, vertebrates)
Protostomes
(worms, arthropods, mollusks)
FUNGI
Cnidaria
(anemones, jellyfish)
Porifera
(sponges)
Basidiomycota
PLANTAE
Ascomycota
Zygomycota
Amoebozoans
Angiosperms
(flowering plants)
Gymnosperms
“PROTISTS”
Pteridophyta
(ferns)
Bryophyta
(liverworts, mosses)
Chlorophyta
(green algae)
Rhodophyta
(red algae)
Oomycota
(water molds)
Phaeophyta
(brown algae)
Diatoms
Dinoflagellates
Apicomplexans
Ciliates
Kinetoplastids
Euglenids
Diplomonads
EUKARYOTIC TREE OF LIFE
Fig. 18-7
WHAT ARE THE KEY FEATURES OF
ANIMALS?

Animals possess all of the following
characteristics






Multicellularity
Their cells lack a cell wall
They obtain energy by consuming other organisms
Most reproduce sexually
They are motile at some point in the life cycle
They are able to respond rapidly to external stimuli
AN EVOLUTIONARY TREE OF SOME MAJOR
ANIMAL PHYLA
Fig. 23-1
LACK OF TISSUES SEPARATES SPONGES
FROM ALL OTHER ANIMALS

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Tissues are groups of similar cells that carry
out a specific function (e.g., muscle)
Sponges are the only modern-day animals that
lack tissues
 Individual cells in sponges may be
specialized, but they act independently and
are not organized into true tissues
Sponges and all remaining tissue-containing
phyla arose from an ancient common ancestor
without tissues
PORIFERA (SPONGES)

Sponges have a simple body plan

Sponges belong to the phylum Porifera and are found
in most marine and aquatic environments
Sponges do not move, but occur in a variety of sizes and
shapes
 They may reproduce asexually by budding, where the
adult produces miniature versions of itself that drop off and
assume an independent existence
 They may reproduce sexually through fusion of sperm and
eggs

THE DIVERSITY OF SPONGES
Fig. 23-4
CNIDARIANS

Cnidarians are well-armed predators
Sea jellies, sea anemones, corals, and hydrozoans
belong to the phylum Cnidaria
 These animals are mostly marine and are all
carnivorous predators
 The cells of cnidarians are arranged into distinct
tissues, including a contractile muscle-like tissue and
an organized nerve net

CNIDARIAN DIVERSITY
Fig. 23-6
PLATYHELMINTHES (FLATWORMS)

Flatworms may be parasitic or free living
Flatworms are bilaterally symmetrical and belong to
the phylum Platyhelminthes
 Many species are parasites, organisms that live in
or on the body of another organism
 Non-parasitic, free-living flatworms inhabit aquatic,
marine, and moist terrestrial habitats
 Flatworms can reproduce both sexually and
asexually; most are hermaphroditic, having both
male and female sexual organs

THE LIFE CYCLE OF THE HUMAN PORK
TAPEWORM
1 A human eats
poorly cooked
pork with
live cysts
2 A larval
tapeworm
is liberated by
digestion and
attaches to
the human’s
intestine
adult tapeworm
6 inches
head (attachment site)
3 The tapeworm matures in a human
intestine, producing a series of
reproductive segments; each segment
contains both male and female sex organs
8 The larvae form
cysts in pig muscle
4 Eggs are shed from
the posterior end of the
worm and are passed
with human feces
5 A pig eats food
contaminated by
infected feces
7 The larvae migrate through
blood vessels to pig muscle
6 Larvae hatch
in the pig’s intestine
Fig. 23-10
PLATYHELMINTHES (FLATWORMS)

Another group of parasitic flatworms is the
flukes
Flukes have complex life cycles that include an
intermediate host, such as a snail
 Blood flukes cause schistosomiasis, which causes symptoms
such as diarrhea, anemia, and possible brain damage
 As many as 200 million people worldwide may be infected
with flukes

FLATWORM DIVERSITY
Fig. 23-9
ANNELIDA (SEGMENTED WORMS)

Annelids are segmented worms and belong to the
phylum Annelida

The annelid body is divided into a series of repeating
units (segmentation)

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The segments contain identical copies of nerves, excretory
structures, and muscles that allows for complex movement
Annelids have a fluid-filled coelom

The coelom functions as a hydrostatic skeleton, where
pressurized fluid provides a framework against which
muscles can act
DIVERSE ANNELIDS
Fig. 23-12
MOLLUSCA

The three classes of mollusks are:
Gastropods
 Bivalves
 Cephalopods
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MOLLUSCA

Gastropods are one-footed crawlers

The snails and slugs are collectively known as
gastropods
They have a muscular foot for locomotion
 They may possess a shell, but not all gastropods are shelled
 They feed using a radula, a flexible ribbon studded with
spines that scrape algae from rocks or grasp larger plants
or prey
 Most use their skin and gills for respiration, but terrestrial
mollusks have a simple lung

MOLLUSCA

Bivalves are filter feeders

Bivalves include scallops, oysters, mussels, and clams
They live in fresh water and marine habitats
 They possess two shells that can be clamped shut by a
strong muscle
 They are filter feeders and use gills for both feeding and
respiration
 Most have a muscular foot used for burrowing or for
attaching to rocks

MOLLUSCA

Cephalopods are marine predators

Cephalopods have tentacles with chemosensory
abilities and suction disks

The tentacles are used for locomotion and to capture prey
These animals are able to move rapidly by forcefully
expelling water from the mantle cavity
 They possess closed circulatory systems

THE DIVERSITY OF CEPHALOPOD
MOLLUSKS
Fig. 23-16
ARTHROPODS

Arthropods are the most diverse and abundant
animals
The phylum Arthropoda includes insects, arachnids,
myriopods, and crustaceans
 Arthropods have appendages and an exoskeleton
(external skeleton)

The exoskeleton is secreted by the epidermis (the outer
layer of skin)
 It is composed primarily of protein and chitin (a
polysaccharide)

THE EXOSKELETON MUST BE MOLTED
Fig. 23-18
THE DIVERSITY OF ARACHNIDS
Fig. 23-22
THE DIVERSITY OF MYRIAPODS
Fig. 23-23
THE DIVERSITY OF CRUSTACEANS
Fig. 23-24
ECHINODERMS
Echinoderms have a calcium carbonate skeleton
 The phylum Echinodermata includes sand
dollars, sea urchins, sea stars, sea cucumbers,
and sea lilies

Echinoderm larvae exhibit bilateral symmetry; adults
show radial symmetry
 They exhibit deuterostome development
 They possess an endoskeleton (internal skeleton)
that sends projections through the skin

THE DIVERSITY OF ECHINODERMS
Fig. 23-27
PHYLUM

CHORDATA
The phylum Chordata includes two invertebrate
groups (the sea squirts and the lancelets) plus
the vertebrates