AP Biology CMR Unit 6 Ch. 18 Evolution of Animal Diversity @ SOHI ‘99 B.Rife page 5 /
Unit 6 The Evolution of Animal Diversity - Chapter 18
University of Minnesota.
Department of Ecology, Evolution, and Behavior.
URL: http://biosci.cbs.umn.edu/class/biol/1106/
General Zoology (BIOL 1106)
Note-Taking Hints
At the beginning of the course and periodically throughout the quarter, review the following list of major systems. When you are taking notes in lecture, when reading the textbooks, and during lab make sure you have filled in information about all of the following. If a certain system is absent or reduced, and therefore only briefly covered, then record that in your notes. Then, when reviewing for quizzes or exams, use the facts recorded for each of these systems in each of the major Phyla or Classes in making a detailed study outline and/or flashcards. Or make a Phylum Review Table
Biology 1106 Guide to Major Systems and Concepts:
Phylum:
Taxonomic Classes:
Examples (common names) from Lab or Lecture:
Etymology (origin of the word) or other "name games" to help you remember the above:
Body Plan (Symmetry etc...): Body Wall:
Feeding, Digestion: Circulation:
Excretion: Respiration:
Nervous System: Muscles & Locomotion:
Arrangement:
Sense Organs:
Reproduction: Morphology:
Asexual, Sexual or Both?
Monoecious (hermaphroditic) or Dioecious?
Other Interesting Behaviors: Phylogeny:
Happy note taking, don't cramp your hand or you won't do well on the dissections!!!!!!!
For more on Outline Methods, go to the Animal World at a Glance Page.
For more details, go to the Zoological Concepts Page.
For more on how to use the Phylum and Class Pages, go to the Phyla Index Page.
For another review technique, go to the Phyla Comparison Page.
Go to the Zoology Home Page.
Tree of Life http://phylogeny.arizona.edu/tree/
Overview of all Phyla Page 1 of 2
I. Kingdom Protista
Subkingdom Protozoa- the single celled "animals"
1. Phylum Sarcomastigophora
a. Subphylum Sarcodina-the amebas (Amoeba)
b. Subphylum Mastigophora-the flagellates (Euglena)
2. Phylum Ciliophora- the ciliates (Paramecium)
3. Phylum Apicomplexa- (Plasmodium)
II. Kingdom Animalia
A. Phylum Porifera- the sponges
B. Phylum Cnidaria
1. Class Hydrozoa- (Hydra, Obelia)
2. Class Syphozoa- the true jellyfish (Aurelia)
3. Class Anthozoa- the "flower" animals (sea anenome, corals)
C. Phylum Platyhelminthes- the flat "worms"
1. Class Turbellaria- (Planaria)
2. Class Cestoda- (tapeworms)
3. Class Trematoda- (flukes)
D. Phylum Nematoda- the round "worms"- (Ascaris)
E. Phylum Mollusca
1. Class Bivalvia- "two valves"- (clams, mussels)
2. Class Gastropoda- "stomach foot- (snails, slugs)
3. Class Cephalopoda- "head foot"- (squid, octopus, nautilus)
F. Phylum Annelida- the segmented worms
1. Class Polychaeta-"many hairs"- (clamworms)
2. Class Oligochaeta- "few hairs"- (earthworms)
3. Class Hirudinea- (leeches)
G. Phylum Arthropoda
1. Subphylum Chelicerata-
a. Class Meristomata-"thigh mouth" (horseshoe crab)
b. Class Arachnida-(spiders, ticks, scorpions)
2. Subphylum Crustacea-(lobster, shrimp, crab, crayfish)
3. Subphylum Uniramia-
a. Class Diplopoda-"2 feet"- (millipedes)
b. Class Chilopoda-" "- (centipedes)
c. Class Insecta- (butterflies, ants, crickets, roaches)
*You may need to know some insect Orders.
H. Phylum Echinodermata- "spine skin"
1. Class Asteroidea- (sea stars)
2. Class Ophiuroidea- (brittle stars)
3. Class Holothuroidea- (sea cucumbers)
4. Class Echinoidea- (sea urchins, sand dollars)
5. Class Crinoidea- (sea lilies, feather stars)
Overview of all Phyla Page 2 of 2
I. Phylum Chordata-
1. Subphylum Urochordata- "tail cord"- (tunicates)
2. Subphylum Cephalochordata- "head cord"- (Amphioxus)
3. Subphylum Vertebrata- "backboned"
a. Superclass Aganatha- "without jaws"- (lamprey)
b. Superclass Gnathostomata- "jawed mouth"
1. Class Chondrichthyes
-the cartilaginous "fish"- (sharks, rays)
2. Class Osteichthyes
-the bony fish- (perch)
3. Class Amphibia
-Orders: Anura, Caudata, Gymnophiona
4. Class Reptilia
-Orders:Squamata, Testudines, Crocodilia
5. Class Aves
-Orders: Lots!, see Class Page
6. Class Mammalia
-Orders: Lots!, see Class Page
Phylum Porifera The Sponges
"Sponges are the simplest multicellular animals. Because the cell is the elementary unit of life, the evolution of organisms larger than unicellular protozoa arose as an aggregate of such building units. There are many advantages to multicellularity as opposed to simply increasing the mass of a single cell. Since it is at cell surfaces that exchange takes place, dividing a mass into smaller units greatly increases the surface area available for metabolic activities. Thus multicellularity is a highly adaptive path toward increasing body size."
Major Characteristics of Phylum Porifera
1 Multicellular; body a loose aggregation of cells of mesenchymal origin;
2 Body with pores (ostia), canals, and chambers that serve for passage of water;
3 All aquatic; mostly marine;
4 Symmetry radial or none;
5 Epidermis of flat pinacocytes; most interior surfaces lined with flagellated collar cells (choanocytes) that create water currents; a gelatinous protein matrix called mesoglea contains amebocytes, collencytes, and skeletal elements;
6 Skeletal structure of fibrillar collagen (a protein) and calcareous or siliceous crystalline spicules, often ombined with variously modified collagen (spongin) fibrils;
7 No organs or true tissues; digestion intracellular; excretion and respiration by diffusion;
8 Reactions to stimuli apparently local and independent; nervous system probably absent;
9 All adults sessile and attached to substratum;
10 Asexual reproduction by buds or gemmules and sexual reproduction by eggs and sperm; free- swimming ciliated larvae.
Sponges are differentiated by the type of canal system
Asconoids - Small and tube shaped. Water enters through microscopic dermal pores into a large cavity called the spongocoel, which is lined with choanocytes. The choanocyte flagella pull the water through the pores and expel it through the single osculum.
Syconoids - Syconoid sponges also have a tubular body and single osculum, but the body wall is thicker and more complex. Water enters through incurrent canals that deliver it to radial canals, which are lined with choanocytes. The radial canals then empty into the spongocoel, which is lined with epithelial cells and not with choanocytes.
Leuconoids - Leuconoid sponges have the most complexity and are the best adapted for increase in sponge size. Most leuconoids form large colonial masses, each member of the mass having its own osculum, but individual members are poorly defined and often impossible to distinguish. Clusters of flagellated chambers are filled from incurrent canals and discharge water into excurrent canals that eventually lead to the osculum.
Phylum Cnidaria
"... many cnidarians are very effective predators that are able to kill and eat prey much more highly organized, swift, and intelligent. They manage these feats because they possess tentacles bristling with tiny, remarkably sophisticated weapons called nematocysts.
A nematocyst is secreted within the cell that contains it. As it is secreted, it is endowed with the potential energy to power its discharge. Achieving a velocity of 2 m/sec, it instantly penetrates its prey and injects a paralyzing toxin."
Major Characteristics of Phylum Cnidaria
1 Entirely aquatic; some in fresh water but mostly marine;
2 Radial symmetry or biradial symmetry around a longitudinal axis with oral and aboral ends; no definite head;
3 Two basic body forms: polyp and medusa;
4 Exoskeleton or endoskeleton of chitinous, calcareous, or protein components in some;
5 Body with two layers, epidermis and gastrodermis; with mesoglea (diploblastic); mesoglea with cells and connective tissue in some (triploblastic);
6 Gastrovascular cavity or coelenteron (often branched or divided with septa) with a single opening that serves as both mouth and anus; extensible tentacles usually encircling the mouth or oral region;
7 Special stinging cell organelles called nematocysts in either or both epidermis and gastrodermis; nematocysts abundant on tentacles, where they may form batteries or rings;
8 Nerve net with symmetrical and asymmetrical synapses; some sensory organs; diffuse conduction;
9 Muscular system (epitheliomuscular type) of an outer layer of longitudinal fibers at base of epidermis and an inner one of circular fibers at base of gastrodermis; modifications of this plan in anthozoans, such as separate bundles of independent fibers in the mesoglea;
10 Reproduction by asexual budding (in polyps) or sexual reproduction by gametes (in all medusae and some polyps; sexual forms monoecious or dioecious; planula larva; holoblastic cleavage;
11 No excretory or respiratory systems
12 No coelomic cavity
Classes of Cnidarians:
Class Hydrozoa - Most hydrozoans are marine and colonial in form, and typically include both the medusa and polyp stage in their life cycle. Some, however, have no medusa stage, and some occur only as medusae and have no polyp stage.
Examples: Hydra, Obelia
Class Scyphozoa - Class Scyphozoa includes most of the larger "jellyfishes". A few, such as Cyanea, may attain a bell diameter exceeding 2 m and tentacles 60 to 70 m long, but most range from 2 cm to 40 cm in diameter. Their polyp stage is absent or greatly reduced, and the medusae of this class have no velum.
Examples: Aurelia, Cyanea
Class Anthozoa - Anthozoa means "flower animal," and anthozoans are indeed polyps with a flowery appearance. They do not have a medusa stage. Anthozoans are all marine and are found all over the world, in various sizes and habitats.
Examples: Sea anemones, corals
Phylum Platyhelminthes The Flat "Worms"
"... if an animal is active in seeking food, shelter, home sites, and reproductive mates, it requires a different set of strategies [than the radiate animals] and a new body organization.
The ... acoelomate phyla considered [here] are not greatly advanced in organization over the Radiata except in symmetry. The evolutionary consequence of that advancement alone was enormous, however, for it is the type of symmetry assumed by all more complex animals."
Major Characteristics of Phylum Platyhelminthes
1 Three germ layers (triploblastic);
2 Bilateral symmetry; definite polarity of anterior and posterior ends;
3 Body flattened dorsoventrally in most; oral and genital apertures mostly on ventral surface;
4 Body with multiple reproductive units in one class (Cestoda);
5 Epidermis may be cellular or syncytial (ciliated in some);
6 Muscular system of mesodermal origin, in the form of a sheath of circular, longitudinal, and oblique layers beneath the epidermis or tegument;
7 No internal body space (acoelomate) other than digestive tube; spaces between organs filled with parenchyma;
8 Digestive system incomplete (gastrovascular type), absent in some;
9 Nervous system consisting of a pair of anterior ganglia with longitudinal nerve cords connected by transverse nerves and located in the parenchyma in most forms; similar to cnidarians in forms with more primitive characters;
10 Simple sense organs, eyespots in some;
11 Excretory system of two lateral canals with branches bearing flame cells (protonephridia), lacking in some forms;
12 Respiratory, circulatory, and skeletal systems lacking;
13 Most forms monoecious; reproductive system complex, usually with well-developed gonads, ducts, and accessory organs; internal fertilization; life cycle simple in free-swimming forms and those with single hosts; complicated life cycle often involving several hosts in many internal parasites;
14 Class Turbellaria mostly free-living; classes Trematoda and Cestoda entirely parasitic.
Classes of flat "worms":
Class Turbellaria - Turbellarians are mostly free-living worms than range in length from 5 mm or less to 50 cm. Usually covered with ciliated epidermis, they are typically creeping worms that combine muscular with ciliary movement to achieve locomotion. The mouth is on the ventral side.
Example: Dugesia
Class Trematoda - The trematodes are all parasitic flukes, and as adults they are almost all found as internal parasites of vertebrates.
Examples: Clonorchis, Schistosoma
Class Cestoda - The cestodes, or tapeworms, usually have long flat bodies made up of many reproductive units (proglottids) and have no digestive system. They also have a specialized structure called the scolex ("holdfast") which is the organ by which they attach to their host. It is usually provided with suckers and often with hooks or spiny tentacles.
Examples: Taenia
Phylum Nematoda The Round "Worms"
"Nematodes are abundant over most of the world, yet most people are only occasionally aware of them as parasites of humans or of their pets. We are not aware of the millions of these worms in the soil, in ocean and freshwater habitats, in plants, and in all kinds of other animals. Their dramatic abundance moved N.A. Cobb to write in 1914: 'If all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes and oceans represented by a thin film of nematodes.' "
Major Characteristics of Phylum Nematoda
1 Body bilaterally symmetrical, cylindrical in shape;
2 Body covered with a secreted, flexible, nonliving cuticle;
3 Motile cilia and flagella completely lacking; some sensory endings derived from cilia present;
4 Muscles in body wall running in longitudinal direction only;
5 Excretory system of either one or more gland cells opening by an excretory pore, a canal system without gland cells, or both gland cells and canals together; flame cell protonephridia lacking;
6 Pharynx usually muscular and triradiate in cross section;
7 Male reproductive tract opening into rectum to form a cloaca; female reproductive tract opening a separate gonopore;
8 No true coelom; body cavity is the pseudocoel, a space between the gut and the mesodermal and ectodermal components of the body wall which is not lined with peritoneum; derived from the embryonic blastocoel rather than a secondary cavity within the mesoderm;
9 Fluid in pseudocoel enclosed by cuticle forming a hydrostatic skeleton;
Example: Ascaris
Other pseudocoelomate phyla:
Phylum Rotifera - Rotifera derive their name from their characteristic ciliated crown, or corona, which gives the impression of a rotating wheel when beating.
Phylum Mollusca
"Next to Arthropoda, the phylum Mollusca has the most named species in the animal kingdom -- probably about 50,000 living species, not to mention some 35,000 fossil species discovered to date. The name Mollusca indicates one of their distinctive characteristics: a soft body."
Major Characteristics of Phylum Mollusca
1 Body bilaterally symmetrical (bilateral asymmetry in some); unsegmented, usually with definite head;