Download Chapter 18 The Phyla - Not covered in class

Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
Plants, fungi and animals each branched independently from an ancestral protist…
Here we will focus on the animal branch…
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
Shown to the right is the
animal branch leading to the
nine major phyla
- know this tree: the
criteria for branching (no
tissues vs. true tissues,
etc…) and the order in
which the various phyla
branched off.
Fig. 18.23
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animals
A. Multicellular, heterotrophic eukaryotes
B. Obtain nutrients by ingestion
- in contrast to fungi, which digest OUTSIDE body and then absorb it
C. Lack cell walls found in plants and fungi
- use special extracellular matrices and intercellular junction
D. Most are diploid and reproduce sexually
E. Most have muscle cells for movement and neurons for signaling
F. Most are invertebrates (lack a vertebral column or backbone)
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
A. Porifera (pore-bearer in latin)
i. sponges
ii. Sessile = Stationary (don’t move)
iii. Only 9000 species, most (8900) marine (salt water)
iv. Radial symmetry
- body parts arranged
around a central axis
Fig. 18.3B
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
A. Porifera (pore-bearer in latin)
v. Body has two layers of cells
- inner layer of flagellated cells
sweep water up through
central cavity
vi. Suspension (filter) feeders
- collect food particles from
water passed thru foodtrapping equipment
- bacteria that enter pores are trapped in
mucus of flagellated cells and engulfed by
phagocytosis
Fig. 18.3C
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
A. Porifera (pore-bearer in latin)
vii. Simples of ALL animals
- no nerves
- no muscles
- believed to have arose very
early from earliest animal
kingdom ancestor
- really just a glorified colony of
protists
Fig. 18.3C
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
sea anemone
I. Animal Phyla
B. Cnidarians (coelenterates)
i. Hydras, jellyfish, sea anemones and corals
ii. Radial symmetry
iii. ~10,000 species, mostly marine
iv. Two body forms: polyp and medusa
Fig. 18.4
Fig. 18.4
- polyp: settled on solid surface with tentacles and mouth opening
upward
- medusa: swimming form with mouth tentacles downward
- some species take both forms during their life cycle
- others take one or the other (hydra and sea anemones
always polyps)
- polyp form is typically asexual and medusa for is sexual
- sea anemones reproduce by fission, hydras by budding
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
B. Cnidarians (coelenterates)
v. carnivores: use tentacles to capture prey (small
animals and protists) and push into mouth
- http://www.youtube.com/watch?v=M3VSvyxrwXA
tentacles
mouth
Daphnia (food) in
Gastrovascular cavity
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
B. Cnidarians (coelenterates)
vi. Food enters and undigested food exits mouth
- NO anus
vii. Only two cell layers thick (no mesoderm germ layer) - represents
very early phlya of animal kingdom (branched off very early after
porifera)
viii. Gastrovascular cavity
- Gastro: site of digestion and absorption
- vascular: site of circulation as well
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
B. Cnidarians (coelenterates)
ix. Cnidocytes (stinger cells)
- cell after which the phylum is
named
- found on surface of tentacles
Fig. 18.4
- each cell contains a coiled thread with a capsule
(nematocyst)
- each cell contains a coiled thread with a capsule
(nematocyst)
- when triggered, coil shoots out and wraps around/stings prey
x. Simple nervous system (see Chapter 28)
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
II. Bilateral symmetry (we will return to phlya in a second)
A. Most animals have bilateral symmetry
- similar left and right side (can be
divided equally by a single cut)
- anterior: the head
- posterior: tail
- dorsal: back surface (our back)
- ventral: bottom surface (our
stomach surface)
Fig. 18.5
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla (We’re back)
C. Platyhelminthes (Greek platys, flat, and helmis, worm)
i. Flatworms (ribbon-like)
ii. ~20,000 species
iii. Found in marine, freshwater and damp terrestrial habitats
(these are free-living)
iv. Many are also parasitic
Parasitic tapeworm
from human intestines
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
C. Platyhelminthes (Greek platys, flat, and helmis, worm)
v. Bilateral symmetry
- left and right side that look the same
vi. Have a gastrovascular cavity similar to cnidarians
- this is unlike most bilateral animals
vii. Use cilia to move over surfaces (they are slow)
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
C. Platyhelminthes (Greek platys, flat, and helmis, worm)
vii. Three major groups of flatworms
1. Planarian: represents the free-living flatworms
- head and two eye spots
- flap on each side of head detects chemicals in water
- has a nervous system (see chapter 28)
- mouth on ventral surface
Fig. 18.6
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
C. Platyhelminthes (Greek platys, flat, and helmis, worm)
vii. Three major groups of flatworms
2. Flukes
- parasites, obtain nutrients from host
Fig. 18.6
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
C. Platyhelminthes (Greek platys, flat, and helmis, worm)
vii. Three major groups of flatworms
3. Tapeworms
- parasites, obtain nutrients from host
Fig. 18.6
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
III. Body Cavities (Another aside…)
A. Most animals have a body cavity
- body cavity = fluid-filled space between digestive
tract and the body wall
- porifera, cnidaria and platyhelminthes LACK a body cavity (all
other animals have one)
*They are called Acoelomates (“a-”, without, “coelum”, body cavity)
Platyhelminthes - notice there is NO
fluid-filled space between dig. tract
(from endoderm) and body covering
(from ectoderm). It is all filled with
tissue from mesoderm.
Fig. 18.7
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
III. Body Cavities (Another aside…)
A. Most animals have a body cavity
- pseudocoelum: a body cavity not completely lined
by mesoderm derived tissue
Ex. Roundworms from phylum Nematoda
Fig. 18.7
Nematoda - notice there is a body
cavity, but only the outside is lined
with mesoderm dervied tissue. The
inside is lined with endoderm derived
tissue
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
III. Body Cavities (Another aside…)
A. Most animals have a body cavity
- coelum: a body cavity COMPLETELY lined by
mesoderm derived tissue
Ex. Roundworms from phylum Nematoda
Fig. 18.7
Annelida - notice the true body cavity
there are two here) is lined on all
sides by mesoderm dervied tissue
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
III. Body Cavities (Another aside…)
A. Most animals have a body cavity
i. REVIEW
1. Acoelomates
2. Psuedocoelomates
3. Coelomates
i. Advantages of having a body cavity
1. Flexibility for movement (not as flexible if your solid)
2. Can serve as a hydroskeleton
3. Organs are housed in Coelom and protected by
the fluid.
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
D. Nematoda
i. roundworms
a. Have an exoskeleton called a cuticle
- molts cuticle as it grows
b. Complete digestive tract (alimentary canal)
Fig. 18.8
c. No circulatory system
d. Fluid in pseudocoelom
- distributes nutrients (circulation)
- serves as a hydroskeleton
e. Among most numerous of animals in number and species
- 90,000 known species (probably 10X this exist)
- found anywhere there is rotting organic matter
- some are parasitic
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
E. Mollusca
i. Snails, slugs, oysters, clams, octopus, squid…
ii. More than 150,000 known species
iii. Most have soft body protected by hard exoskeleton
iv. Although diverse, the basic body plan of all
mollusks:
a. Muscular foot - locomotion
b. Mantle - secretes a shell
c. Radula - a rasping tongue
v. True Coelom
vi. Most have open circ. System
except cephalopods (squid, octopus)
which have closed
Fig. 18.9
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
E. Mollusca
vii. Classes
- gastropods = slugs and snails
- bivalves = clams, mussels, oysters, scallops
- cephalopods = nautilus, squid, octopus
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
IV. Many animals have segmented bodies
A. Segmentation
i. Subdivision of body along its length into repeated parts
ii. Obvious in Earthworm:
Fig. 18.10
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
IV. Many animals have segmented bodies
A. Segmentation
iii. Insects are segmented: head, thorax, abdomen
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
IV. Many animals have segmented bodies
A. Segmentation
iv. Humans are segmented:
Two examples:
vertebrae
Abdominal muscles
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
F. Annelida
i. Segmented body resembling series of fused rings
ii. 15,000 species
iii. 1mm to 3m long giant Earthworm of Australia
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
F. Annelida
iv. Earthworms, polychaetes, Leeches
polychaetes
Fig. 18.11
Leech
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
F. Annelida
iv. Earthworms, polychaetes, Leeches
v. True coelom
- hydrostatic skeleton
vi. Skin-breathers, nephridia, closed circulatory system, nervous
system, complex digestive system (know the details)
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
G. Arthropods
i. Most numerous and widespread of all animals
- estimated at 1018 individuals on Earth
- most successful phyla of animals to have ever existed
- more species than ALL other phyla combined (estimated 4 to 6
million species)
ii. Crayfish, lobsters, crabs, barnacles, spiders (arachnids), ticks,
insects, millipedes, centipedes…
iii. Have jointed appendages (arthron = joint, pous = foot; Greek)
iv. Exoskeleton (protein and chitin)
- must molt as it grows
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
G. Arthropods
v. Structure of an arthropod (notice segmentation and appendages)
Fig. 18.12
vi. Open circulatory system
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
H. Echinodermata
i. Sea stars, sand dollars, sea urchins
ii. 7,000 species, all marine
Sea stars
iii. Radial symmetry
- larval stage is BILATERAL, indicating they are not closely related
Fig. 18.14
to other radial organisms like cnidarians
iv. No segmentation
v. Endoskeleton
vi. Spiny skin
Sea Urchins
Brittle star
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
http://www.youtube.com/watch?v=4IRF-pKVtuU
H. Echinodermata
vii. Water vascular system
- unique to echinoderms
- network of water-filled canals that branch into
extensions called tube feet
- tube feet function in locomotion, feeding and
gas exchange (they are like little suction cups)
Fig. 18.14
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
i. This is our phylum
ii. Four distinctive features (appear in embryos and sometimes adults)
1. Dorsal, hollow nerve cord
2. notochord
- flexible, supportive, longitudinal rod
3. Pharyngeal slits
- gill structures in the pharynx (not necessarily working gills)
4. Post-anal tail
- a tail posterior to the anus
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
iii. Vertebrates are the most diverse members
a. have a segmented backbone
iv. Two groups of chordates (and all other animals for that matter) are
invertebrates: tunicates and lancelets
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
a. Tunicates (sea squirts)
- stationary, adhere to rocks, boats coral
reefs
- ADULTS have no trace of notochord,
nerve cord or tail
- pharyngeal slits are present in adults
and function in feeding
- suspension feeders
- larva is swimming and has all four
chordate trademarks
Fig. 18.15
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
Fig. 18.15
b. lancelets
- resemble tunicate larva
- suspension feeders using
pharyngeal slits
- live in marine sands
- show all four chordate characteristics
- segmented muscles for slow swimming
movements
- the closest living invertebrate relative of vertebrates
according to molecular evidence
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
Fig. 18.15
I Chordates
v. The vertebrates
- fish, amphibians, reptiles, birds, mammals
- notochord present during embryogenesis, but replaced with a
vertebral column that protects dorsal spinal cord.
- have bony or cartilaginous endoskeletons, chambered hearts,
increasingly complex nervous systems
- organs contained in coelom
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
Fig. 18.15
I Chordates
v. The vertebrates
a. The agnathans (Greek a- without, and gnathos, jaws)
- group of primitive vertebrates that lack paired fins and jaws (all
other vertebrates have jaws)
- lampreys are members of this group
- 35 species worldwide
lampreys parasitizing a fish
lamprey’s jawless mouth
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
v. The vertebrates
b. First jawed vertebrates were fishes
- replaced most agnathans 400 million years ago
- jaws were critical in vertebrate evolution!! Chordates no longer
had to be mud-suckers or suspension feeders, they could go
catch and eat prey!
Origin of vertebrate jaws
Fig. 18.17
Chapter 18: The Evolution of
Animal Diversity
Chondrichthyes
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
Fig. 18.18
- Two major classes of fished
1. Condrichthyes - cartilaginous fishes (sharks, rays and skates)
- skeleton made of cartilage
- 750 living species
2. Osteichthyes - bony fish (the others)
- largest group of vertebrates
- 30,000 species
- have swim bladders (gas-filled
sacs) for regulating buoyancy
Osteichthyes
Chapter 18: The Evolution of
Animal Diversity
Chondrichthyes
AIM: What major types of animals have evolved?
I. Animal Phyla
Fig. 18.18
I Chordates
v. The vertebrates
c. Two major adaptations were important to set stage for
vertebrates to colonize the land
1. Air sacs - allowed some fish in shallow water to absorb
oxygen from air for short periods
2. Lobed fins - allowed some degree of movement on land
- all lobe fin fish are extinct except
for one species
Osteichthyes
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
Fig. 18.19
I Chordates
v. The vertebrates
d. Amphibians evolved from fish around 350 million years ago
- first terrestrial vertebrates
- amphibios, “living a double life” in Greek
- most live in close association with water
- typically simple lungs or gills supplemented with skin-breathing
- lack hard shells and need to be in water
- larva live in water and
metamorphose into the adult form
- frogs, toads and salamanders
- 4800 species and rapidly declining
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
Fig. 18.20
I Chordates
v. The vertebrates
e. Reptiles
- became independent of water thanks to evolution of hardshelled eggs that don’t dry out on land
- evolved more effective lungs and heart, and thicker dry skins
- gave reptiles a greater metabolic activity than amphibians
- 6500 species of lizards, snakes, turtles, crocodiles, and alligators
- ectothermic (cold-blooded)
- some small dinosaurs may have been
endothermic including the lineage that led
to the warm-blooded flying reptiles we call
birds…
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
Fig. 18.21
I Chordates
v. The vertebrates
f. Birds (class Aves)
- evolved from reptilian relatives of dinosaurs
- developed wings, feathers, and light bones for flying
- four-chambered hearts
- unique lungs to supply the intense metabolic needs of flight
- hard-shelled eggs and great deal of parental care
during development and maturation
- Archaeopteryx - famous transitional fossil
Archaeopteryx
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
Fig. 18.21
I Chordates
v. The vertebrates
g. mammals
- have hair, sweat glands, mammary glands, four-chambered hearts
- evolved 200 million years ago
- coexisted with dinosaurs until they went extinct 65 MYA at which time they
evolved into the dominant terrestrial vertebrates in many ecosystems
- regulate body temperature extremely well
- most provide lots of parental care
Archaeopteryx
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
v. The vertebrates
g. mammals
- monotremes (e.g. duck-billed platypus)
i. Lay eggs
- Marsupials
i. Development internally using a yolk and continue
development after birth
ii. Once wide-spread across the globe, but pushed out by a more
successful crew…the placental mammals (Australia was isolated so
they could survive there - a safe haven)
- placental mammals (Eutherians)
i. Gestate young to more mature state and nutrition/waste removal
provided by mom via placenta
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
I Chordates
v. The vertebrates
g. mammals
- primates
i. Opposable thumbs, stereoscopic vision for depth perception,
adapted for life in the trees
ii. We have many of these traits in a slightly modified form (we
obviously don’t do well in trees anymore)
iii. Many have complex social structures
Chapter 18: The Evolution of
Animal Diversity
AIM: What major types of animals have evolved?
I. Animal Phyla
J. Phylogenetic tree of
animal diversity
- know this tree: the
criteria for branching (no
tissues vs. true tissues,
etc…) and the order in
which the various phyla
branched off.
Fig. 18.23