Transcript Topic 5.3 Classification Invertebrates & Vertebrates

TOPIC 5.3 CLASSIFICATION OF BIODIVERSITY
ESSENTIAL IDEA: SPECIES ARE NAMED AND
CLASSIFIED USING AN INTERNATIONALLY AGREED
SYSTEM
UNDERSTANDINGS:
• The binomial system of names for species is universal among biologists
and has been agreed and developed at a series of congresses.
• When species are discovered they are given scientific names using the
binomial system.
• Taxonomists classify species using a hierarchy of taxa.
• All organisms are classified into three domains.
• The principal taxa for classifying eukaryotes are kingdom, phylum, class,
order, family, genus and species.
• In a natural classification, the genus and accompanying higher taxa consist
of all the species that have evolved from one common ancestral species.
• Taxonomists sometimes reclassify groups of species when new evidence
shows that a previous taxon contains species that have evolved from
different ancestral species.
• Natural classifications help in identification of species and allow the
prediction of characteristics shared by species within a group.
TOPIC 5.3 CLASSIFICATION OF BIODIVERSITY
ESSENTIAL IDEA: SPECIES ARE NAMED AND
CLASSIFIED USING AN INTERNATIONALLY AGREED
SYSTEM
Applications and skills:
• Application: Classification of one plant and one animal species from
domain to species level.
• Application: Recognition features of bryophyta, filicinophyta,
coniferophyta and angiospermophyta.
• Application: Recognition features of porifera, cnidaria, platylhelmintha,
annelida, mollusca, arthropoda and chordata.
• Application: Recognition of features of birds, mammals, amphibians,
reptiles and fish.
• Skill: Construction of dichotomous keys for use in identifying specimens.
CLASSIFICATION OF
INVERTEBRATE ANIMALS
Topic 5.3
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
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
LACK OF TISSUES SEPARATES SPONGES
FROM ALL OTHER ANIMALS



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
 found in most marine and aquatic environments
 occur in a variety of sizes and shapes
 may reproduce asexually by budding or sexually
through fusion of sperm and eggs

CNIDARIANS
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 musclelike tissue and an
organized nerve net

PLATYHELMINTHES (FLATWORMS)
may be parasitic or free living in aquatic, marine,
and moist terrestrial habitats
 are bilaterally symmetrical
 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

ANNELIDA (SEGMENTED WORMS)

The annelid body is divided into a series of repeating
units (segmentation)


Annelids have a fluid-filled coelom


The segments contain identical copies of nerves, excretory
structures, and muscles that allows for complex movement
The coelom functions as a hydrostatic skeleton, where
pressurized fluid provides a framework against which
muscles can act
One way digestive tract
MOLLUSCA

The three classes of mollusks are:
Gastropods
 Bivalves
 Cephalopods

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
 These animals are able to
move rapidly by forcefully
expelling water from the
mantle cavity
 They possess closed
circulatory systems

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
calcium carbonate skeleton
 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

PHYLUM

CHORDATA
The phylum Chordata includes two invertebrate
groups (the sea squirts and the lancelets) plus
the vertebrates
CLASSIFICATION OF
VERTEBRATE ANIMALS
TOPIC 5.3 CLASSIFICATION OF BIODIVERSITY
ESSENTIAL IDEA: SPECIES ARE NAMED AND
CLASSIFIED USING AN INTERNATIONALLY AGREED
SYSTEM
Applications and skills:
• Application: Classification of one plant and one animal species from
domain to species level.
• Application: Recognition features of bryophyta, filicinophyta,
coniferophyta and angiospermophyta.
• Application: Recognition features of porifera, cnidaria, platylhelmintha,
annelida, mollusca, arthropoda and chordata.
• Application: Recognition of features of birds, mammals, amphibians,
reptiles and fish.
• Skill: Construction of dichotomous keys for use in identifying specimens.
Jaws
Vertebral column
Skull
Dorsal nerve cord, notochord,
pharyngeal gill slits, post-anal tail
Lungs
Lobed fins
Mammalia
(mammals)
Reptilia
(turtles, snakes
crocodiles,
birds)
Amphibia
(frogs,
salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fish)
Chondrichthyes
(sharks, rays)
Petromyzontiformes
(lampreys)
Vertebrates
Tetrapods
Hair, milk
Amniotic egg
Limbs
AN
EVOLUTIONARY
TREE OF THE
VERTEBRATES
VERTEBRATE ADAPTATIONS

Several adaptations have allowed vertebrates to successfully
invade most habitats




presence of an internal skeleton that can grow and repair itself
allowed for greater size and mobility, enabling these animals to
invade most habitats
Jaws evolved to allow these animals to exploit a much wider
range of food sources than jawless animals that preceded them
The development of paired appendages (fins, legs, wings)
helped to stabilize movement
The increased size and complexity of the brain and sensory
structures allowed these animals to perceive their environment
in detail and to respond in a variety of ways
WHAT ARE THE MAJOR GROUPS OF
VERTEBRATES?

Today, vertebrates include the following groups:







Lampreys
Cartilaginous fishes
Ray-finned fishes
Lungfishes
Amphibians
Reptiles (and birds)
Mammals
LAMPREYS





Some
lampreys
parasitize
fish
jawless
rounded
sucker that
surrounds
the mouth
spinal cord is
protected by
cartilaginous
segments
live in both
fresh and salt
waters
CARTILAGINOUS FISHES

Cartilaginous fishes
are marine predators
They are of the class
Chondrichthyes, and
include sharks,
skates, and rays
 Most are marine
 They possess jaws
and a cartilaginous
skeleton
 Their body is
protected by a
leathery skin
embedded with tiny
scales

BONY FISHES
 the


most diverse vertebrates
Bony fish are found in nearly every watery
habitat, both freshwater and marine
This group includes:
Ray-finned fishes, such as the angler fish, the
moray eel, and the sea horse
 Lobe-finned fishes, which include the lungfish
and the coelacanth

THE DIVERSITY OF RAY-FINNED FISHES

most diverse and abundant group of vertebrates






Fins which are formed by webs of skin supported by bony
spines
bony skeleton
skin is covered with interlocking scales
two-chambered heart
gills are for respiration
Most have a swim bladder
LOBED-FINNED FISHES

fleshy fins that contain rod-shaped bones
surrounded by a thick layer of muscle

Some of these modified fleshy fins could be used to drag
the fish from a drying puddle to a deeper pool


This gave rise to the first vertebrates to invade land—the
amphibians
Some of the lineages of lobefins left descendents that
survive today and are the tetrapods (amphibians,
reptiles, and mammals)
Amphibians:







frogs, toads, salamanders, and
caecilians
Amphibians begin life adapted to an
aquatic environment (e.g., tadpoles
have gills)
They later mature into semiterrestrial adults with lungs
three-chambered heart
adults respire through lungs and
moist skin
Most have four limbs
Most are confined to moist habitats
use of external fertilization requires
water

eggs, protected only by a jelly-like
coating, are vulnerable to water loss
REPTILES

class Reptilia and are adapted for
life on land

These animals evolved from an
amphibian ancestor about 250 million
years ago






Reptiles include lizards, snakes,
alligators, crocodiles, turtles, and birds
They respire exclusively through lungs
tough scaly skin that protects the body
and resists water loss
internal fertilization with shelled
amniotic egg
three- or four-chambered hearts
efficient lungs and do not use their skin
as a respiratory organ
BIRDS


distinctive group of reptiles
 They appear in the fossil
record 150 million years
ago
 They are distinguished
from other reptiles by
feathers, which are
highly specialized
reptilian body scales
Modern birds retain scales
on their legs, which is
evidence of the ancestry they
share with the rest of the
reptiles
 The earliest known bird
is called Archaeopteryx
ARCHEOPTERYX, THE EARLIEST-KNOWN
BIRD
MAMMALS









Mammals appeared in the fossil record about 250 million years ago
They did not diversify and dominate terrestrial habitats until the
dinosaurs became extinct (65 million years ago)
Mammals are warm-blooded with high metabolic rates
a four-chambered heart
hair that protects and insulates
legs designed for running rather than crawling
provide milk to their offspring
sweat, scent, and sebaceous (oil-producing) glands, which are not
found in other vertebrates
Mammals are subdivided into three groups



Monotremes
Marsupials
Placental mammals
MONOTREMES

are egg-laying mammals

This group includes only three species, the platypus and two
species of spiny anteater (echidnas), and are found only in
Australia and New Guinea
Platypuses forage for food in the water and eat small vertebrate and
invertebrate animals
 Echidnas are terrestrial and eat insects and worms they dig out of the
ground


Monotremes lay leathery eggs rather than giving birth to live
young

The newly hatched young are nourished from milk secreted by the
mother
MARSUPIA
Species include the opossums, koalas, kangaroos,
wallabies, wombats, and the Tasmania devil
 In marsupials, embryos begin development in the uterus
of the female

Young are born at a very immature stage and must crawl to and
grasp a nipple to complete development
 Post-birth development, in most, is completed in a protective
pouch

PLACENTAL MAMMALS


inhabit land, air, and sea
This highly diverse class
includes bats, moles, impalas,
whales, seals, monkeys, and
cheetahs
The uterus contains a
placenta that functions in
gas, nutrient, and waste
exchange between circulatory
systems of mother and embryo
 In placental mammals, young
are retained in the uterus for
their entire embryonic
development
