Download 30-1 The Chordates

Biology
Slide
1 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
Slide
2 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
What Is a Chordate?
What characteristics do all chordates
share?
Slide
3 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
What Is a Chordate?
What Is a Chordate?
Members of the phylum Chordata are called
chordates.
A chordate is an animal that has, for at
least some stage of its life:
• a dorsal, hollow nerve cord;
• a notochord;
• pharyngeal pouches;
• and a tail that extends beyond the
anus.
Copyright Pearson Prentice Hall
Slide
4 of 25
30-1 The Chordates
What Is a Chordate?
Characteristics of Chordates
Muscle segments
Tail
Anus
Notochord
Hollow nerve cord
Mouth
Pharyngeal pouches
Slide
5 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
What Is a Chordate?
The notochord is a long supporting rod that runs
through the body just below the nerve cord.
Notochord
Slide
6 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
What Is a Chordate?
Pharyngeal pouches are paired structures in the
throat (pharynx) region.
Pharyngeal pouches
Slide
7 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
What Is a Chordate?
The tail can contain bone and muscle and is used for
swimming by many aquatic species.
Tail
Slide
8 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
Most Chordates Are Vertebrates
Most Chordates Are Vertebrates
About 96 percent of all chordate species are
vertebrates.
Most vertebrates have a vertebral column, or
backbone.
In vertebrates, the dorsal, hollow nerve cord is
called the spinal cord.
As a vertebrate embryo develops, the front end of
the spinal cord grows into a brain.
Copyright Pearson Prentice Hall
Slide
9 of 25
30-1 The Chordates
Nonvertebrate Chordates
Nonvertebrate Chordates
The two groups of nonvertebrate
chordates are tunicates and lancelets.
Slide
10 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
Most Chordates Are Vertebrates
Phylogeny of Chordates
Sharks
& their
Jawless
relatives
fishes
Nonvertebrate
chordates
Bony
fishes
Reptiles Birds
Amphibians
Mammals
Invertebrate ancestor
Slide
11 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
Nonvertebrate Chordates
Tail
Tunicates
Hollow
nerve cord
The larval form of
filter-feeding
tunicates have all of
the chordate
characteristics. Mouth
Pharynx
with gill
slits
Wasteeliminating
organ
Notochord
Intestine
Stomach
Heart
Larva
Slide
12 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
Nonvertebrate Chordates
Adult filter-feeding tunicates have neither a notochord
nor a tail.
Siphon to mouth
Pharynx with gill slits
Siphon from anus
Anus
Tunic
Intestine
Reproductive organs
Heart
Stomach
Adult
Copyright Pearson Prentice Hall
Slide
13 of 25
30-1 The Chordates
Nonvertebrate Chordates
An adult lancelet has a definite head region that
contains a mouth.
As water passes through the pharynx, a sticky mucus
catches food particles.
The lancelet swallows the mucus into the digestive
tract.
Mouth
Pharynx with gill slits
Slide
14 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
Nonvertebrate Chordates
Lancelets use the pharynx for gas exchange.
Lancelets are thin enough to exchange gases
through their body surface.
Lancelets have a closed circulatory system and do
not have a true heart.
Slide
15 of 25
Copyright Pearson Prentice Hall
30-1 The Chordates
Most Chordates Are Vertebrates
Phylogeny of Chordates
Sharks
& their
Jawless
relatives
fishes
Nonvertebrate
chordates
Bony
fishes
Reptiles Birds
Amphibians
Mammals
Invertebrate ancestor
Slide
16 of 25
Copyright Pearson Prentice Hall
30-1
Click to Launch:
Continue to:
- or -
Slide
17 of 25
Copyright Pearson Prentice Hall
30-1
A characteristic of most, but not all, chordates is
a. pharyngeal pouches.
b. a backbone.
c. a hollow nerve cord.
d. a tail that extends beyond the anus.
Slide
18 of 25
Copyright Pearson Prentice Hall
30-1
In vertebrates, the developing backbone
replaces the
a. pharyngeal pouches.
b. hollow nerve cord.
c. notochord.
d. siphon and tunic.
Slide
19 of 25
Copyright Pearson Prentice Hall
30-1
To which group of vertebrates are tunicates
most closely related?
a. amphibians
b. fishes
c. reptiles
d. mammals
Slide
20 of 25
Copyright Pearson Prentice Hall
30-1
An animal that retains a notochord as an
adult is a
a. tunicate.
b. lancelet.
c. fish.
d. reptile.
Slide
21 of 25
Copyright Pearson Prentice Hall
30-1
In the lancelet, the pharynx and gill slits are
used for
a. feeding and gas exchange.
b. reproduction and excretion.
c. circulation and sensory detection.
d. movement and digestion.
Slide
22 of 25
Copyright Pearson Prentice Hall
END OF SECTION