College Biology - Problem Drill 15: The Evolution of Animal Diversity Question No. 1 of 10 1. Which is not a feature of the phyla porifera- sponges? Question #01 (A) Most are marine animals. (B) They have a radial symmetry. (C) They have ability to reorganize themselves back into shape. (D) They have segmentation. (E) They live attached to their substrate. A. Incorrect! Sponges are mostly marine animals. This is a feature of sponges. Sponges have radial symmetry. This is a feature of sponges. Sponges have the ability to reorganize themselves back into shape. This is a feature of sponges. D. Correct! Sponges lack segmentation. This is not a feature of sponges. Sponges live attached to their substrate. This is a feature of sponges. Most sponges are marine and live singly. They live attached to a substrate and ranges in height from 1 cm to 2 m. Sponges belong to the phylum porifera. These marine animals are built on a body plan with a radial symmetry. Sponges have similar shapes as mirror images and have the ability to reorganize themselves back into shape. The correct answer is (D).
Question No. 2 of 10 2. The first major split in evolution was between which phyla? Question #02 (A) Parazoa vs. the eumetazoa (B) Radiata vs. bilateria (C) Protosomes vs. deuterosomes (D) Acoelomates vs. coelomates (E) None of the above A. Correct! This was the first true split that divided animals based on true tissues. Radiata vs. bilateria split: radiata are those animals with radial symmetry and are diploblastic (e.g., cnidaria). Bilateria are all other animal groups, which are bilateral, symmetric, and are triploblastic. Protosomes vs. deuterosomes split: organisms in which a second opening serves as the mouth are protosomes. Organisms in which the second hole serves as the anus are deuterosomes. Acoelomate vs. coelomate split: acoelomates are animals with no coelome (body cavity). Coelomates are all animals with a body cavity. The correct answer is listed in the choices above, so this cannot be correct answer. Parazoa vs. eumetazoa split: The earliest split in evolution was between Parazoa and eumetazoa, which are animals lacking/possessing true tissues. Phylum porifera are the only extant members of the parazoans. The correct answer is (A).
Question No. 3 of 10 3. What is true about the Cambrian evolution? Question #03 (A) It occurred 2 billion years ago. (B) There was a sudden appearance of animals with hard tissues. (C) Meteorites struck the earth. (D) Dinosaurs disappeared. (E) There were no prokaryotes living then. A. Incorrect! It actually occurred about 500 million years ago. This statement above was false. B. Correct! There was an explosion of animals with hard tissues. This statement is true. There is no evidence that a meteorite struck the earth during this period. Dinosaurs did not disappear during this time. There were prokaryotic cells living during this time. About 500 million years ago, extinct animals were identified in fossil records. Soft body fauna species have been dated back to 700 million years, but they lacked sophistication and resembled acoelomates. All surviving animals today can be traced back to their ancestors to this time period. Development of hard body parts, such as teeth, resulted in a more sophisticated diet for both predator and prey. Hard body parts were easily identified from fossil records. The modern phyla evolved during the Cambria period, which occurred about 500 million years ago. This was a 10 million-year period of explosive evolution. No new animal species have been discovered after the Cambrian explosion and it appears that all phyla have been locked in. Some phyla have since become extinct, but there are no new phyla. The correct answer is (B).
Question No. 4 of 10 4. What is the major difference between acoelomates and coelomates? Question #04 (A) Only one has segmentation of the body. (B) Only one has a body cavity. (C) Only one has bilateral symmetry. (D) Only one has a mouth. (E) Only one has radial symmetry. A. Incorrect! This is not a difference between acoelomates and coelomates. B. Correct! The major difference between acoelomates and coelomates is the body cavity. This is not a difference between acoelomates and coelomates. This is not a difference between acoelomates and coelomates. This is not a difference between acoelomates and coelomates. Acoelomates are animals with no body cavity, such as phylum platyhelmenthyes (flatworms), while coelomates have a body cavity. There are also pseudocoelomates that have a false gut cavity, e.g., nematodes. The have no segmentation and no muscles around the digestive tract. Roundworms are classified in the phylum nematode. Advantages of coelome: animals have room for growth of internal organs. They can have a circulatory system and the fluid itself can act as a transport system. The muscles can squeeze fluid and the digestive tract muscles are independent of body wall muscles. The correct answer is (B).
Question No. 5 of 10 5. In which of the following animals is segmentation not seen? Question #05 (A) Sponges (B) Earthworms (C) Leeches (D) Polychaetes (E) B & C A. Correct! Sponges are not segmented organisms. Earthworms are segmented organisms. Leeches are segmented organisms. Polychaetes are segmented organisms. Both earthworms and leeches are segmented organisms. Segmentation is a subdivision of body in repeat parts. This is seen in the phylum Annelida. The Annelids are all bilaterally symmetrical animals. They have a fluidfilled cavity between the outer body wall and the gut. Segmentation provides body flexibility and mobility. Examples are earthworm, leech, and marine worms called polychaetes. The correct answer is (A).
Question No. 6 of 10 6. An organism that has a water vascular system as its unique feature would be found in what phylum? Question #06 (A) Nematoda (B) Arthropoda (C) Echinodermata (D) Platyhelminthes (E) None of the above A. Incorrect! Nematodes do not have a water vascular system. Arthropods do not have a water vascular system. C. Correct! Echinoderms have a water vascular system. Platyhelminthes do not have a water vascular system. The correct answer is listed here among the choice,s so this cannot be the right choice. Echinoderms possess a well-developed skeleton with numerous spines that extend outward to give the animal a spiny appearance. A unique feature is their water vascular system. They are slow-moving animals with a thin skin that covers an exoskeleton. Examples include sea urchins, starfish, brittle stars, and sea cucumbers, which are exclusively marine animals. The correct answer is (C).
Question No. 7 of 10 7. Which of the following is/are basic features of animals? Question #07 (A) Have diploid cells. (B) Undergo only asexual reproduction. (C) Capable of photosynthesis. (D) A & B (E) All of the above A. Correct! Animals do have diploid cells. This is a basic feature. Animals have the ability to undergo sexual, not asexual, reproduction. Animal are not capable of photosynthesis. Animals do have diploid cells, but they do not undergo asexual reproduction. This cannot be the correct choice. All of these statements listed here are not correct. This could not be the right answer. Animals are eukaryotic and multicellular. They are heterotrophs without a cell wall. The life cycle of animals include a diploid adult that produces eggs or sperms by meiosis. They are responsive to their environment. The body of animals becomes fixed as they develop, although some undergo metamorphosis later on. Animals are composed of diploid cells, with the exception of gametes, which are haploid. All animals go through embryonic stages that include the blastula and gastrula. Animals have distinct types of cell junctions. There are some basic features of animals: Animals develop from embryos Animals are characterized by diploid cells. They use sexual reproduction Animals have the ability to develop motile sperm and non-motile eggs. Capable of complex and rapid movement. The correct answer is (A).
Question No. 8 of 10 8. Which animals do not have tissues and have primitive body parts? Question #08 (A) Parazoa (B) Cnidaria (C) Eumetazoa (D) Acoelomates (E) All of the above A. Correct! Parazoa are the organisms with primitive body parts and are those which lack tissues. Cnidaria exhibit radial symmetry. Their body plans have a central tubular body surrounding a gastrovascular opening. Eumetazoa have well-developed tissues and organs. Acoelomates are animals with no body cavity, such as phylum platyhelmenthyes (flatworms). One of the statements listed below is incorrect, so this could not be the answer. Parazoa are the organisms that do not have tissues, and their body parts are primitive. The only surviving members are sponges. Parazoa are asymmetrical. All other animals will display some sort of symmetry. The larvae are planktonic and adults are sessile. The correct answer is (A).
Question No. 9 of 10 9. Which animal(s) has/have a false body cavity lined on the inside by endoderm and on the outside by mesoderm? Question #09 (A) Hookworm (B) Pinworm (C) Filarial worm (D) A & B (E) All of the above A. Incorrect! Hookworm is a type of nematode and possesses these characteristics. It is not the only one listed here. Pinworm is a type of nematode and possesses these characteristics. It is not the only one listed here. Filarial worm is a type of nematode and possesses these characteristics. It is not the only one listed here. Both hookworms and pinworms are types of nematodes and posses these characteristics. They are not the only ones listed here. E. Correct! Of the choices available, all of them are nematode and possess these characteristics. Phylum Nematoda are roundworms. They are pseudocoelomates, which mean they have a false body cavity. Their body cavity is lined on the inside by endoderm and on the outside by mesoderm. The false cavity is used to give animals shape. Examples include hook, ascarid, pin and filarial worms. The correct answer is (E).
Question No. 10 of 10 10. Which phylum has animals with a true circulatory system and a muscular foot and mantle? Question #10 (A) Mollusks (B) Annelida (C) Arthopoda (D) Echinodermata (E) Chordata A. Correct! Mollusks have a common body plan with bilateral symmetry with a complete digestive tract, coelom and internal organs. They have a muscular foot and mantle. The Annelids are segmented worms. Arthropods are segmented, have jointed appendages, and have an exoskeleton composed of chitin. Echinoderms possess a well-developed skeleton with numerous spines that extend outward to give the animal a spiny appearance. A unique feature is their water vascular system. Chordates are animals that share four characteristics during some part of their life cycle. These include a notochord, a dorsal nerve cord, pharyngeal slits, and a postanal tail. Phylum Mollusks posses a true circulatory system. They have bilateral symmetry and a complete digestive tract, coelom and internal organs. The outgrowth of a body surface functions as a shell, sensory reception, and it houses gills. They also have a muscular foot and a mantle. Examples include clams, scallops, and oysters. The correct answer is (A).