Exam 4: Chapter 32
Many animals can be categorized as either protostomes and deuterostomes based on certain features of their embryonic development. Determine whether each of the following terms applies to only protostomes, only deuterostomes, both protostomes and deuterostomes, or neither.
Protosome: Mouth from blastosphere; Spiral, determinate cleavage; coelum from solid masses of mesoderm Deuterostome: Anus from blastosphere; radial, indeterminate cleavage; coelum from folds of archenteron Both: Tripoblast Neither: Diploblast
triploblastic
Protostome and deuterostomes are tripoblastic, diploblastic, or neither?
cleavage
(1) The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane. (2) The succession of rapid cell divisions without significant growth during early embryonic development that converts the zygote to a ball of cells.
Body Cavities (coelom)
- Cushions internal organs - In some, internal skeleton - Allows independent growth & movement of internal organs
The most recently discovered phylum in the animal kingdom (1995) is the phylum Cycliophora. It includes three species of tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk, and collects scraps of food from its host's feeding by capturing the scraps in a current created by a ring of cilia. The body is sac-like and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are eucoelomate, do not molt (though their host does), and their embryos undergo spiral cleavage. Using similarities in embryonic development, body symmetry, and other anatomical features to assign an organism to a clade involves 1. cladistics based on body plan. 2. molecular-based phylogeny. 3. morphology-based phylogeny.
1 and 3
Characteristics of animals
1) All animal share a common ancestor - monophyletic 2) Sponges are basal animals 3) Eumetazoa is a clade of animals with true tissues 4) most animal phyla belong to the clade bilateria 5) there are 3 major clades of bilaterian animals - deuterostomia, lophotrochozoa, ecdysozoa
3 lines of evidence that choanoflagellates are closely related to animals
1) Morphologically, choanoflagellate cells and the collar cells of sponges are almost indistinguishable 2) Similar collar cells have been identified in other animals, but they have never been observed in non-choanoflagellate protists or in plants or fungi 3) DNA sequence data indicate that they and animals are sister groups. Genes for signaling and adhesion proteins previously known only from animals have been discovered in them
Early Embryonic Development in Animals
1) Zygote of an animal undergoes a series of mitotic cell division called cleavage 2) 8-celled embryo is formed by 3 rounds of cell division 3) in most animals, cleavage produces a multicellular stage called a blastula (hollow ball of cells that surround a cavity called the blastocoel) 4) Most animals undergo gastrulation, process in which one end of the embryo folds inward, expands, and eventually fills the blastocoel, producing layers of embryonic tissues; ectoderm and endoderm 5) pouch formed by gastrulation, called archenteron, opens to the outside via the blastospore 6) endoderm of the archenteron develops into the tissue lining the animal's digestive tract
Body plans differentiated by
1.Body symmetry 2.Tissue organization 3.Body cavity -Present •Type -Absent 4.Mode of development A group of animal species with the same level of organizational complexity is called a "GRADE"
Arthropod
1st animals to adapt to terrestrial habitats
diploblastic
2 germ layers
Mesozoic Era
251 - 65.5 million years ago age of reptiles (dinosaurs, small mammals); extinction of dinosaurs at end animals spreading to new habitats
triploblastic
3 germ layers All bilaterian animals are _____ Ex: flatworms, arthropods, vertebrates
With the current molecular-based phylogeny in mind, rank the following from most inclusive to least inclusive. 1. ecdysozoan 2. protostome 3. eumetazoan 4. triploblastic
3, 4, 2, 1
Cenozoic Era
65.5 million yrs ago mass extinction of both terrestrial and marine animals (dinosaurs, marine reptiles) rise of large mammalian herbivores and predators global climate gradually cooled, trigger shift in animal lineages
Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate). Select the three statements that are true. To review the germ layers and the terminology associated with body cavities, see the Hints. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the lining of the digestive tract. A diploblast has no mesoderm. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity. A pseudocoelom has the same functions as a true coelom. An acoelomate triploblast has no endoderm. In a pseudocoelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the muscles. The digestive tract of a coelomate functions as a coelom.
A diploblast has no mesoderm. A pseudocoelom has the same functions as a true coelom. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity.
Which of the following is radially symmetrical? See Concept 32.3 (Page 677) a dog an automobile a spoon a submarine sandwich a doughnut
A doughnut
body cavity
A fluid- or air-filled space between the digestive tract and the body wall. used for cushioning of organs, prevent internal injury
larva
A free-living, sexually immature form in some animal life cycles that may differ from the adult in morphology, nutrition, and habitat.
- Look for cell walls under a microscope. BC fungus have cell walls made up of chitin and humans have none
A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus? - Look for cell walls under a microscope. - Determine whether it is unicellular or multicellular. - Figure out whether it is autotrophic or heterotrophic. - See if it is a eukaryote or prokaryote. - See if it reproduces sexually.
blastula
A hollow ball of cells that marks the end of the cleavage stage during early embryonic development in animals.
Germ layers, tissues, and body cavities Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate). Select the three statements that are true. To review the germ layers and the terminology associated with body cavities, see the Hints.
A pseudocoelom has the same functions as a true coelom. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity. A diploblast has no mesoderm. Triploblasts have tissues derived from three embryonic germ layers: endoderm inside, ectoderm outside, and mesoderm in the middle. The three basic body plans of triploblasts relate to the presence or absence of a body cavity. No body cavity: acoelomate. Body cavity lined on the inner side by endoderm-derived tissue and on the outer side by mesoderm-derived tissue: pseudocoelomate. Body cavity lined entirely by mesoderm-derived tissue: coelomate.
Cambrian Explosion
A relatively brief time in geologic history when large, hard-bodied forms of animals with most of the major body plans known today appeared in the fossil record. This burst of evolutionary change occurred about 535-525 million years ago (Paleozoic Era). oldest fossils of about half of all extant animal phyla (arthropods, chordates, echinoderms)
radial cleavage
A type of embryonic development in deuterostomes in that the planes of cell division that transform the zygote into a ball of cells are either parallel or perpendicular to the polar axis, thereby aligning tiers of cells one above the other.
indeterminate cleavage
A type of embryonic development in deuterostomes, in which each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo.
spiral cleavage
A type of embryonic development in protostomes in which the planes of cell division that transform the zygote into a ball of cells are diagonal to the vertical axis of the embryo. As a result, the cells of each tier sit in the grooves between cells of adjacent tiers.
determinate cleavage
A type of embryonic development in protostomes that rigidly casts the developmental fate of each embryonic cell very early.
Based on the tree presented in Figure 32.11 in your textbook, which statement is false?
Acoelomate flatworms are more closely related to echinoderms than to annelids.
Which of the following statements is correct? See Concept 32.4 (Page 680) Eumetazoans have three embryonic tissue layers. The origin of all extant animal phyla can be traced to the Cambrian explosion. Sponges are diploblastic animals. All animals share a common ancestor. Most animal phyla belong to the clade Radiata.
All animals share a common ancestor
gastrulation
Among the characteristics unique to animals is?
d. has an aggregation of sensory
An important trend in animal evolution was cephalization. An animal is said to show cephalization when it _____. a. has bilateral symmetry b. has tissue specialization c. is large d. has an aggregation of sensory neurons at the anterior end e. has a hard, outer covering
A diploblast has no mesoderm. A pseudocoelom has the same functions as a true coelom. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity.
Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate). Select the three statements that are true. To review the germ layers and the terminology associated with body cavities, see the Hints. A diploblast has no mesoderm. A pseudocoelom has the same functions as a true coelom. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity. The digestive tract of a coelomate functions as a coelom. An acoelomate triploblast has no endoderm. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the lining of the digestive tract. In a pseudocoelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the muscles.
Early embryonic development
Animal tissues develop from embryonic layers Animals may be diploblastic or triploblastic
Identify the features that distinguish animals from organisms in other multicellular kingdoms. -Animals are motile. -Animals are ingestive heterotrophs. -Animals have sensory organs at their anterior end.
Animals are ingestive heterotrophs
Identify the features that distinguish animals from organisms in other multicellular kingdoms. Select all that apply. Animals are motile. Animals are ingestive heterotrophs. Animals have sensory organs at their anterior end.
Animals are ingestive heterotrophs
Identify the features that distinguish animals from organisms in other multicellular kingdoms.
Animals are ingestive heterotrophs.
Animals probably evolved from colonial protists. How do animals differ from these protist ancestors?
Animals have more cells than their protist ancestors, and their cells show greater specialization.
invertebrates
Animals without backbones, 95% of animal species
not yet known, but if they were ancetor would have to have a simple nervous system, saclike gut w/ single opening, and no excretory syst
Are acoelomate flatworms basal bilaterians?
still a hypothesis bc have true tissues and don't resemble cells of choanoflagellates
Are ctenophores basal metazoans?
yes, but were once thought to be paraphyletic
Are sponges monophyletic (single phylum)?
Animals vary tremendously in structure. Nevertheless, they can be categorized into a few basic body plans based on body symmetry, number of embryonic germ layers, type (or absence) of body cavity, and characteristics of embryonic development. Part A - Identifying body symmetry Which type of symmetry does each of the following animals display? Drag each picture to the appropriate bin.
Asymmetry: Sponge Radial Symmetry: Jelly, Hydra Bilateral Symmetry: Bobcat, Turtle, Snake, Octopus
Which type of symmetry does each of the following animals display? Drag each picture to the appropriate bin.
Asymmetry: Sponge Radial Symmetry: Jelly, Hydra Bilateral Symmetry: Bobcat, Turtle, Snake, Octopus
Acoelomate flatworms are more closely related to echinoderms than to annelids. bc they are EQUALLY related
Based on the tree in Figure 32.11, which statement is false?
What is the probable sequence in which the following animal clades originated, from earliest to most recent? deuterostomes, bilaterians, amniotes, vertebrates, tetrapods deuterostomes, bilaterians, vertebrates, tetrapods, amniotes bilaterians, deuterostomes, vertebrates, tetrapods, amniotes bilaterians, deuterostomes, amniotes, vertebrates, tetrapods
Bilaterians, deuterostomes, vertebrates, tetrapods, amniotes
coelomate
Body cavity lined entirely by mesoderm-derived tissue
pseudocoelomate
Body cavity lined on the inner side by endoderm-derived tissue and on the outer side by mesoderm-derived tissue
bilateral symmetry
Body symmetry in which a central longitudinal plane divides the body into 2 equal but opposite halves may have sensory equipment in anterior end, include CNS move fast and are active All are triploblastic
The earliest ancestors of about half of all extant animal phyla can be traced back to the _____ explosion.
Cambrian This saw the culmination of the rapid diversification of animals that began in the late Precambrian.
The earliest ancestors of about half of all extant animal phyla can be traced back to the _____ explosion. See Concept 32.2 (Page 675) Devonian Pleistocene Jurassic Carboniferous Cambrian
Cambrian This saw the culmination of the rapid diversification of animals that began in the late Precambrian.
The earliest ancestors of about half of all extant animal phyla can be traced back to the _____ explosion.
Cambrian. This saw the culmination of the rapid diversification of animals that began in the late Precambrian.
Which of the following is characteristic of protostomes?
Cell fate is determined early during embryonic development; This is known as determinate development and is characteristic of protostomes.
Animal Kingdom Origin
Choanoflagellates are closely related to animals - DNA seq. data - Morphologically indistinguishable - similar collar cells found in other animal but not in non-choanoflagellate protists, plants, or funi
Which of these statements, if accurate, would support the claim that the ancestral cnidarians had bilateral symmetry? Cnidarians have fewer Hox genes than bilaterians. All cnidarians are acoelomate. Cnidarian larvae possess anterior-posterior, left-right, and dorsal-ventral aspects. The presence of collar cells.
Cnidarian larvae possess anterior-posterior, left-right, and dorsal-ventral aspects.
What was an early selective advantage of a coelom in animals? A coelom _____. allowed asexual and sexual reproduction contributed to a hydrostatic skeleton, allowing greater range of motion was a more efficient digestive system allowed cephalization and the formation of a cerebral ganglion
Contributed to a hydrostatic skeleton, allowing greater range of motion
Which feature of deuterostome development explains the formation of identical human twins?
Deuterostomes have indeterminate development.
Which feature of deuterostome development explains the formation of identical human twins? Deuterostomes have indeterminate development. In deuterostomes, the blastopore becomes the anus. Deuterostomes have radial cleavage.
Deuterostomes have indeterminate development.
Which feature of deuterostome development explains the formation of identical human twins?
Deuterostomes have indeterminate development. Most deuterostomes have indeterminate cleavage, meaning that each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo. For example, if the cells of a sea urchin embryo are isolated at the four-cell stage, each can form a complete larva. It is the indeterminate cleavage of the human zygote that makes identical twins possible
Select the correct statement(s) about animal body plans.
Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes).
Select the correct statement(s) about animal body plans. Select all that apply. Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes). All triploblastic animals possess a coelom. In both protostomes and deuterostomes, the blastopore develops into the mouth.
Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes).
HUMANS
During embryological development, the anus forms before the mouth in _____. - arthropods - humans - flatworms - earthworms - slugs
Tissues are formed by germ layers
Ectoderm - Outer coverings - Sometimes CNS Mesoderm - Muscle - Most organs between digestive tract & outer covering Endoderm - Digestive tract lining - Some organs -- Liver, lungs
Kingdom Animalia
Eukaryotic - lack cell walls Multicellular - Unique intercellular junctions Common set of ECM molecules - Includes collagen, - proteoglycans.. have unique cells and tissues
Which example below is a current hypothesis regarding the Cambrian explosion?
Evolution of the Hox gene complex provided developmental flexibility
While looking at some seawater through your microscope, you spot the egg of an unknown animal. Which of the following tests could you use to determine whether the developing organism is a protostome or a deuterostome? See whether the embryo _____. develops an archenteron exhibits spiral cleavage or radial cleavage develops a blastopore develops germ layers
Exhibits spiral cleavage or radial cleavage
Which of the following animals does NOT have a body cavity? See Concept 32.3 (Page 678) earthworm mouse clam flatworm nematode
Flatworm
Which of the following animals does NOT have a body cavity? -earthworm -nematode -mouse -clam -flatworm
Flatworms are acoelomates, even those that are not classified as acoels.
Which of the following occurred during the Mesozoic era?
Flight evolved in pterosaurs and birds
One hypothesis suggests that the Cambrian explosion was caused by the rise of predator-prey relationships. This hypothesis is best supported by an increased incidence of which of the following fossil traces? worm burrows hard parts organic material larger animals
Hard parts
An important trend in animal evolution was cephalization. An animal is said to show cephalization when it _____. See Concept 32.3 (Page 677) has bilateral symmetry has tissue specialization is large has an aggregation of sensory neurons at the anterior end has a hard, outer covering
Has an aggregation of sensory neurons at the anterior end
During embryological development, the anus forms before the mouth in _____. See Concept 32.3 (Page 679) flatworms humans slugs earthworms arthropods
Humans
- Animals are ingestive heterotrophs.
Identify the features that distinguish animals from organisms in other multicellular kingdoms. Select all that apply. - Animals are motile. - Animals have sensory organs at their anterior end. - Animals are ingestive heterotrophs.
gastrulation
In animal development, a series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three-layered embryo, the gastrula.
deuterostome development
In animals, a developmental mode distinguished by the development of the anus from the blastopore; often also characterized by radial cleavage and by the body cavity forming as outpockets of mesodermal tissue most are interdeterminate cleavage
body plan
In animals, a set of morphological and developmental traits that are integrated into a functional whole—the living animal.
protosome development
In animals, developmental mode distinguished by the development of the mouth from the blastopore; often also characterized by spiral cleavage and by the body cavity forming when solid masses of mesoderm split. most are determinate cleavage
Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by ________. preying on animals consuming living, rather than dead, prey ingesting materials using enzymes to digest their food
Ingesting materials
Nutrition mode of Kingdom Animalia
Ingestive heterotrophs - Digest, absorb nutrients within body
A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus?
Look for cell walls under a microscope. Fungal cells have cell walls, and animal cells do not.
A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus? See Concept 32.1 (Page 672) Figure out whether it is autotrophic or heterotrophic. See if it reproduces sexually. Look for cell walls under a microscope. Determine whether it is unicellular or multicellular. See if it is a eukaryote or prokaryote
Look for cell walls under a microscope. Fungal cells have cell walls, and animal cells do not.
A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus?
Look for cell walls under a microscope. Fungal cells have cell walls, and animal cells do not.
eumetazoans
Member of a clade of animals with true tissues. All animals except for sponges
Life Cycle of animals
Most animals have life cycles with larval stages which undergo metamorphosis to an adult stage Larval stage is often the feeding/dispersal stage - May be longest stage
Use the information to answer the question. Trichoplax adhaerens is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. Individual animals move using cilia, and any "edge" can lead. T. adhaerens feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. T. adhaerens sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage. T. adhaerens' body symmetry seems to be most like that of ________. worms most sponges tetrapods cnidarians
Most sponges
All animals can trace their lineage to a common ancestor that lived in the _____.
Neoproterozoic era The common ancestor is likely to have been a protist that lived during the Neoproterozoic
All animals can trace their lineage to a common ancestor that lived in the _____. See Concept 32.2 (Page 673) Jurassic Devonian Cenozoic Neoproterozoic era Pliocene
Neoproterozoic era The common ancestor is likely to have been a protist that lived during the Neoproterozoic.
All animals can trace their lineage to a common ancestor that lived in the _____.
Neoproterozoic era. The common ancestor is likely to have been a protist that lived during the Neoproterozoic.
Which of the following is (are) unique to animals? nervous system signal conduction and muscular movement flagellated gametes heterotrophy the structural carbohydrate, chitin
Nervous system signal conduction and muscular movement
mesoderm
One of the three primary (embryonic) germ layers formed during gastrulation. ultimately forms 'middle' structures such as bones, muscles, blood vessels, heart, kindeys, etc.
The figure shows a cross section of a coelomate showing a coelom and a cross section of a pseudocoelomate showing a pseudocoelom. What is the key difference between a coelom and a pseudocoelom? Pseudocoeloms arose early in animal evolution and evolved into coeloms. Only a coelom is fully lined with mesoderm tissue. A coelom is a true body cavity, whereas a pseudocoelom is a false coelom that is not fully functional.
Only a coelom is fully lined with mesoderm tissue.
What is the key difference between a coelom and a pseudocoelom?
Only a coelom is fully lined with mesoderm tissue. A coelom is formed from mesoderm tissue, whereas a pseudocoelom is formed from mesoderm and endoderm and is not fully lined with mesoderm
Body symmetry
Oral (top) & aboral (bottom) only Body symmetry fits lifestyle Anterior (front, head end) Posterior (back, tail end)
As you are on the way to Tahiti for a vacation, your plane crash lands on a previously undiscovered island. You soon find that the island is teeming with unfamiliar organisms, and you, as a student of biology, decide to survey them (with the aid of the Insta-Lab Portable Laboratory you brought along in your suitcase). You select four organisms and observe them in detail, making the notations found in the figure. Which organism would you classify as an animal? organism A organism B organism C organism D
Organism C
Gastrulation is the process that directly forms the _____. See Concept 32.3 (Page 679) primary germ layers blastula central nervous system organs muscles
Primary germ layers
Differences in development between protostomes and deuterostomes Many animals can be categorized as either protostomes and deuterostomes based on certain features of their embryonic development. Determine whether each of the following terms applies to only protostomes, only deuterostomes, both protostomes and deuterostomes, or neither. Drag each item to the appropriate bin. To review protostome and deuterostome characteristics, see the Hints.
Protostomes and deuterostomes differ in several aspects of their early embryonic development.
Hox genes
Regulate development of body form Animals have unique set of regulatory genes
B) The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old. Not A bc says ORGANISMS and is supposed to be ANIMALS
Select the correct statement about the evolution of animals. Select the correct statement about the evolution of animals. A) Approximately half the phyla of living organisms are found in Cambrian sediments. B) The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old. C) No animal fossils are found in strata formed before the Cambrian explosion.
C) Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes). Not A bc acoelomates are triploblastic
Select the correct statement(s) about animal body plans. A) All triploblastic animals possess a coelom. B) In both protostomes and deuterostomes, the blastopore develops into the mouth. C) Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes).
true tissues
The distinction bw sponges and other animal phyla is based MAINLY on the absence versus the presence of
archenteron
The endoderm-lined cavity, formed during the gastrulation process, that develops into the digestive tract of an animal.
Select the correct statement about the evolution of animals.
The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old.
Select the correct statement about the evolution of animals. The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old. No animal fossils are found in strata formed before the Cambrian explosion. Approximately half the phyla of living organisms are found in Cambrian sediments.
The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old.
Select the correct statement about the evolution of animals.
The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old; The Ediacaran biota was a group of early animals. Some are sponges, whereas others may be related to living cnidarians. Still others of these fossil organisms have proven difficult to classify
blastopore
The opening of the archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes
ectoderm
The outermost of the three primary germ layers in animal embryos; gives rise to the outer covering and, in some phyla, the nervous system, inner ear, and lens of the eye. CNS in some animals
What do all deuterostomes have in common?
The pore (blastopore) formed during gastrulation becomes the anus.
In the traditional phylogeny (A), the phylum Platyhelminthes is depicted as a sister taxon to the rest of the protostome phyla and as having diverged earlier from the lineage that led to the rest of the protostomes. In the molecular phylogeny (B), Platyhelminthes is depicted as a Lophotrochozoan phylum. What probably led to this change? The removal of the acoel flatworms (Acoela) from the Platyhelminthes allowed the remaining flatworms to be a monophyletic clade clearly tied to the Lophotrochozoa. Platyhelminthes' close genetic ties to the arthropods became clear as their Hox gene sequences were studied. Platyhelminthes ceased to be recognized as true protostomes. All Platyhelminthes must have a well-developed lophophore as their feeding apparatus.
The removal of the acoel flatworms (Acoela) from the Platyhelminthes allowed the remaining flatworms to be a monophyletic clade clearly tied to the Lophotrochozoa.
Which characteristic below is shared by plants, fungi, and animals?
They are multicellular eukaryotes.
Which of the following is NOT a characteristic of all animals? See Concept 32.3 (Page 677) They are all multicellular. They are heterotrophic. They have tissues, organs, and organ systems. They are eukaryotes. They ingest their food.
They have tissues, organs, and organ systems.
Which of the following is NOT a characteristic of all animals? -They are all multicellular. -They are heterotrophic. -They have tissues, organs, and organ systems. -They ingest their food. -They are eukaryotes.
They have tissues, organs, and organ systems. Sponges are considered animals, and they lack these levels of organization.
Which of the following is NOT a characteristic of all animals?
They have tissues, organs, and organ systems. sponges are animals but they do not have these
Which of the following is NOT a characteristic of all animals?
They have tissues, organs, and organ systems. Sponges are considered animals, and they lack these levels of organization.
The most ancient branch point in animal phylogeny is the characteristic of having _____. a body cavity or no body cavity radial or bilateral symmetry true tissues or no tissues diploblastic or triploblastic embryos
True tissues or no tissues
Among protostomes, which morphological trait has shown the most variation? type of symmetry (bilateral versus radial versus none) type of development (protostome versus deuterostome) type of body cavity (coelom versus pseudocoelom versus no coelom) number of embryonic tissue types (diploblasty versus triploblasty)
Type of body cavity
- Deuterostomes have indeterminate development. BC retain the capacity to develop into a complete embryo
Which feature of deuterostome development explains the formation of identical human twins? - Deuterostomes have radial cleavage. - Deuterostomes have indeterminate development. - In deuterostomes, the blastopore becomes the anus
- the movement of animals onto land
Which of the following was probably the least important factor in bringing about the Cambrian explosion? - the emergence of predator-prey relationships among animals - the accumulation of diverse adaptations, such as shells and different modes of locomotion - the movement of animals onto land - the evolution of Hox genes that controlled development - the accumulation of sufficient atmospheric oxygen to support the more active metabolism of mobile animals
Cleavage Pattern
With indeterminate cleavage, cells retain totipotency
In a phylogenetic tree, a lineage that diverges from all other members of its group early in the evolutionary history of the group is described as
a basal taxon. In a phylogenetic tree that is rooted, a branch point within the tree (often drawn farthest to the left) represents the most recent common ancestor of all taxa in the tree. A lineage that diverges from all other members of its group early in the history of a group is called a basal taxon. Hence, a basal taxon lies on a branch that diverges near the common ancestor of the group. Sister taxa are groups of organisms that share a common ancestor that is not shared by any other group.
Which of the following is a tetrapod? a. a bird b. an amphibian c. a fish d. a mammal e. a reptile
a bird; an amphibian; a mammal; a reptile
A true coelom is __________.
a body cavity lined with mesoderm; A true coelom is a fluid-filled body cavity lined with tissue derived from mesoderm.
Which of the following is a trait shared by protostomes and deuterostomes?
a body cavity; Protostomes and deuterostomes have a body cavity, although the way that it forms is different.
shared characteristics of chordates: dorsal, hollow nerve cord
a bundle of nervous tissue running the length of the body; may develop into the brain and spinal cord
Which of the following is radially symmetrical?
a doughnut A doughnut has no front, no back, no left, and no right.
Which of the following is radially symmetrical?
a doughnut. A doughnut has no front, no back, no left, and no right.
shared characteristics of chordates: notochord
a flexible rod that runs along the anterior-posterior axis; may be associated with a jointed skeleton
During the development of most animals, cleavage leads to __________.
a multicellular blastula; The blastula is a multicellular stage, which in many animals takes the form of a hollow ball.
shared characteristics of chordates: muscular, post-anal tail
a structure that contains muscles and extends past the anus; may be used to propel some species in water
Which of these primate groups is most closely related to humans? a. apes b. Old World monkeys c. lorises d. prosimians e. New World monkeys
a. apes
Which of the following statements about bird evolution are accurate based on the evidence presented? a. feathers may have originally evolved for interspecies communication and display b. feathered birds, capable of flight, evolved after the extinction of dinosaurs c. the evolution of feathers and other characteristics of birds occurred in a linear progression d. feathers may have originally evolved for insulation
a. feathers may have originally evolved for interspecies communication and display d. feathers may have originally evolved for insulation
Tiktaalik had a combination of fishlike and tetrapod-like characteristics. Which were the tetrapod-like characteristics? a. interlocking ribs b. a neck c. fins with fin rays d. scales e. flat head with eyes on top
a. interlocking ribs b. a neck e. flat head with eyes on top
Which of these anthropoid groups consists of primates who are mostly tree dwellers and whose forelimbs and hind limbs are about equal in length? a. monkeys b. hominids c. prosimians d. primates e. apes
a. monkeys
Why have we NOT found examples in the fossil record of every animal that ever lived on Earth? a. many fossils remain buried. We can only find them when they are exposed by erosion or excavation b. it is just a matter of time before we find them all; rocks contain the history of all life, if you know where to look c. to become a fossil, an animal must remain buried for thousands or millions of years until it turns to rock d. to become a fossil, an animal must be quickly and completely buried in ash or sediment before it has a chance to decompose
a; c; d
Whatever its ultimate cause(s), the Cambrian explosion is a prime example of _____.
adaptive radiation.
both tunicates and lancelets
adults feed with the aid of pharyngeal slits
lancelets
adults swim by the contraction of a series of muscles along the notochord; adults bury themselves into the sediment of the seafloor; all chordate characters present in adults
neither tunicates nor lancelets
adults swim using the vertebral column
coelomates
an animal that posses a true coelom (body cavity lined by tissue completely derived from mesoderm) have internal organs Ex: Earthworm
Ediacaran Biota
an early group of macroscopic, soft-bodied, multicellular eukaryotes known from fossils that rand in age from 635 million to 535 million years ago.
vertebrates
animals with backbones
What is the oldest known primate group? a. apes b. prosimians c. antrhopoids d. Hominids e. Monkeys
b. Prosimians
Which of the following anatomical features of the 3.2 million year old Australopithecus fossil known as Lucy suggest she was a bipedal hominid? a. a hairless face b. a much shorter hipbone that is broader from front to back and wraps around the side c. the absence of a prehensile tail d. a large brain
b. a much shorter hipbone that is broader from the front to back and wraps around the side
Which of the following traits can be used to differentiate humans from our closest living primate relatives? a. grasping hands b. bipedality c. extensive tool use d. large brain size
b. bipedality c. extensive tool use d. large brain size
Which evidence supports the hypothesis that four-limbed animals came from fish? a. fossil evidence shows there have always been four-limbed animals on earth b. fish and four-limbed animals have very similar embryos c. the fossil record shows more and more tetrapod-like fish before the appearance of tetrapods about 365 million years ago d. DNA analysis shows that fish are tetrapods' closest relatives e. both fish and four-limbed animals are vertebrates
b. fish and four-limbed animals have very similar embryos c. the fossil record shows more and more tetrapod-like fish before the appearance of tetrapods about 365 million years ago d. DNA analysis shows that fish are tetrapods' closest relatives e. both fish and four-limbed animals are vertebrates
A key characteristic of modern birds is flight powered by feathered wings. Which of the following pieces of evidence support the hypothesis that the first feathers served a purpose other than flight? a. some birds have feathers but do not fly b. some feathered theropods were not capable of flight c. bats fly but do not have feathers d. Archaeopteryx had flight feathers
b. some feathered theropods were not capable of flight
Which of the following is an accurate statement regarding human evolution? a. once bipedality, tool use, and larger brains evolved in humans, humans stopped evolving b. the fossil record contains creatures with features that are intermediate between those of modern humans and quadrupedal apes c. the first humans evolved in Africa d. in the latest phase of human evolution, there has been a greater reliance on culture
b. the fossil record contains creatures with features that are intermediate between those of modern humans and quadrupedal apes c. the first humans evolved in Africa d. in the latest phase of human evolution, there has been a greater reliance on culture
how did the great transition from fish to tetrapod occur? a. there was no transition, fish and tetrapod have always existed as they are today b. the transition occurred gradually over time, so there are many intermediate forms c. the transition occurred in a few big steps, so there are very few intermediate forms d. the transition occurred in one big step, so there are no intermediate forms
b. the transition occurred gradually over time, so there are many intermediate forms
What kind of habitat did tiktaalik live in? a. tiktaalik lived on dry, rocky slopes b. tiktaalik lived in a warm, freshwater swap c. tiktaalik lived in a shallow, marine environment d. tiktaalik lived in cold, artic tundra
b. tiktaalik lived in a warm, freshwater swamp
What is a transitional fossil? a. transitional fossils only existed for a short period of time b. transitional fossils have features that are intermediate between ancestors and descendants c. transitional fossils were poorly adapted to their environments d. a transitional fossil is in the middle of a direct lineage stretching from ancient forms to organisms alive today
b. transitional fossils have features that are intermediate between ancestors and descendants
pseudocoelomates
body cavity is lined by tissue derived from mesoderm and endoderm NOT FULLY LINED W/ MESODERM Ex: roundworms
Which of these primate groups lives in trees in Central and South America and have nostrils that are wide open and far apart? a. hominids b. apes c. New World monkeys d. anthropoids e. Old World monkeys
c. New World monkeys
The diagnostic feature of Chondrichthyes is: a. a swim bladder b. a streamlined, torpedo-shaped body c. an endoskeleton of calcified cartilage d. a lateral line system e. jaws
c. an endoskeleton of calcified cartilage
The larvae of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following is most directly involved in the evolution of these variations in metamorphosis?
changes in the homeobox genes governing early development.
Ecdysozoa
characteristics shared by nematodes, arthropods, and some others one of the three main lineages of bilaterian animals have only invertebrates exoskeleton molts
Which of the following would you classify as something other than an animal?
choanoflagellates.
Which of the following is a point of conflict between the phylogenetic analyses presented in these two figures?
collagen gene
A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes is absolutely conserved, which of the following would be the best choice on which to base the phylogeny?
collagen genes.
The primates that spend the most time walking upright are: a. apes b. Prosimians c. New World monkeys d. Hominids e. Old World monkeys
d. Hominids
Jaws evolved: a. from arthropod jaws b. from the rasping tongue c. from the bony armor of ostracoderms d. by modification of the skeletal rods that previously supported the anterior pharyngeal gill slits e. by modification of middle ear bones
d. by modification of the skeletal rods that previously supported the anterior pharyngeal gill slits
There are three major groups of mammals categorized on the basis of their: a. method of locomotion b. size c. presence or absence of hair d. method of reproduction e. habitat
d. method of reproduction
metamorphosis
developmental transformation that turns an animal larva into either an adult or an adult-like stage that is not yet sexually mature
trochopore larva
distinctive larval stage observed in some lophotrochozoan animals, including some annelids and molluscs
Which of the following is radially symmetrical?
doughnut
Which of the following is a characteristic of cnidarians?
ectoderm and endoderm; Cnidarians are diploblastic.
Characteristics of animals
eukaryotes multicellular structural support = proteins external to the cell membrane (collagen) cells organized into tissues muscle and nerve cells (allow motility)
The last common ancestor of all animals was probably a
flagellated protist
The last common ancestor of all animals was probably a _____.
flagellated protist.
Which of the following animals does NOT have a body cavity?
flat worm
Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion?
gene duplication
Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion?
gene duplication.
Endoderm
gives rise to lining of digestive tract
Mesoderm
gives rise to muscles and most other organs between the digestive tract (or gut) and the outer covering of the animal.
Ectoderm
gives rise to the outer covering of the animal.
shared characteristics of chordates: pharyngeal clefts
grooves that separate pouches along the side of the pharynx; may develop into parts of the ear
grade
group whose members share key biological features not equivalent to clade
Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?
hard parts.
Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships? The fossil record reveals an increased incidence of _____.
hard parts.
An important trend in animal evolution was cephalization. An animal is said to show cephalization when it _____.
has an aggregation of sensory neurons at the anterior end
An important trend in animal evolution was cephalization. An animal is said to show cephalization when it _____.
has an aggregation of sensory neurons at the anterior end Cephalization is an evolutionary trend toward the concentration of sensory equipment at the anterior end. It is associated with bilateral symmetry.
Which of the following is the most inclusive term for an organism that obtains organic food material by eating other organisms or substances derived from them?
heterotroph Unlike autotrophs (which are also called producers), heterotrophs (which are also called consumers) cannot make their own food. Instead, heterotrophs obtain organic material by feeding on other organisms or their waste products or remains. Obvious examples of heterotrophs include an animal that eats plants or other animals, or a protist that eats other protists. But heterotrophic nutrition also occurs when an organism feeds upon (and breaks down the chemicals found in) organic litter such as carcasses, feces, and fallen leaves; such heterotrophic organisms are known as decomposers.
During embryological development, the anus forms before the mouth in _____.
humans
During embryological development, the anus forms before the mouth in _____. -arthropods -earthworms -flatworms -slugs -humans
humans; During gastrulation, the developing digestive tube of the embryo initially has a single opening, the blastopore. After the archenteron develops, a second opening forms at the opposite end of the gastrula. The mouth of many protostomes develops from the first opening, whereas in deuterostomes the mouth is derived from the second opening.
lophophore
in some lophotrochozoan animals, including brachiopods, a crown of ciliated tentacles, that surround the mouth and function in feeding
Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships?
increased incidence of hard parts in the fossil record
Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by _____.
ingesting it.
endoderm
innermost germ layer; develops into the linings of the digestive tract (archenteron) and much of the respiratory system
tissues
integrated group of cells with a common structure, function, or both
The presence of a coelom is advantageous because __________.
it allows room for the development and movement of internal organs;
Which of the following groups does NOT exhibit bilateral symmetry?
jellies; Individuals in the phylum Cnidaria represent an early branch of the animal kingdom. The other groups mentioned in this question exhibit bilateral symmetry, but jellies exhibit radial symmetry.
Unlike other animals, sponges __________.
lack true tissues; Sponges diverged from the other animals early in their history.
Many young animals are __________, a sexually immature form that is morphologically distinct from the adult stage. These young animals undergo __________ to become __________, which resemble adults but are not yet sexually mature.
larvae ... metamorphosis ... juveniles
One of the primary developmental/anatomical characteristics distinguishing the major animal phyla is the condition of the body cavity. A pseudocoelomate animal is one in which the body cavity is __________.
lined on one side by mesoderm and on the other side by endoderm; If the cavity is not completely lined by tissue derived from mesoderm, it is termed a pseudocoelom.
If you think of the earthworm body plan as a drinking straw within a pipe, where would you expect to find most of the tissues that developed from endoderm?
lining the straw.
bilaterian
member of a clade of animals with bilateral symmetry and 3 germ layers complete digestive tract most of the fossils from the cambrian explosion are from here___ (molliscs, arthropods, chordates, and most other living animal phyla)
Neoproterozoic Era
molecular evidence for multicellular animal The end of the ___ was during an increase in animal diversity this geologic era took place 1 billion to 542 million years ago
tunicates
most chordate characters not present in adults; in adults, water enters through one siphon and leaves through another; larvae swim using the notochord, by adults may be sessile
Which of the following is (are) unique to animals?
nervous system signal conduction and muscular movement.
lophotrochozoa
one of the three main lineages of bilaterian animals have lophophore have only invertebrates
deuterostomia
one of the three main lineages of bilaterian animals include acorn worms & sea stars doesn't mean animals who have deuterostome are part of this clade
What is the key difference between a coelom and a pseudocoelom?
only coelom is fully lined with mesoderm tissue
phylum chordata
only phylum that has vertebrate members also has invertebrates
shared characteristics of chordates: pharyngeal slits
openings to the outside of the body along the side of the pharynx; may develop into gill slits
Hypotheses of declined edicaran after cambrian explosion
predator-prey relationship (natural selection) atmospheric changes changes in development (genetic variation)
Gastrulation is the process that directly forms the _____.
primary germ layers two or three germ layers
Gastrulation is the process that directly forms the _____.
primary germ layers. Gastrulation gives rise to either two or three germ layers.
An animal with a true coelom that has __________ cleavage must be a(n) __________.
radial ... deuterostome; A true coelom is a fluid-filled body cavity lined with mesoderm. Deuterostomes are characterized by radial cleavage.
Reproduction of animals
reproduce sexually diploid stage dominates life cycle
Indeterminate cleavage produces embryonic cells that __________.
retain the capacity to develop into a complete embryo; Each cell produced by the first few mitotic divisions can develop into a complete embryo.
ecdysis
shedding of old exoskeleton
acoelomates
solid-bodied animal lacking a cavity between the gut and outer body wall Ex: Planarians
The zygotes of many protostomes undergo __________ cleavage and __________ cleavage.
spiral ... determinate
radial symmetry
symmetry in which body is shaped like a pie or barrel (lacking a left side and a right side) and can be derived into mirror-imaged halves by any plane through its central axis sessile (living attached to a substrate) planktonic (drifting or weakly swimming, Ex: jellies)
A mutualism is an ecological relationship between two species
that both benefit from the relationship. A mutualism is an ecological relationship in which each species benefits. In some cases, the two species that interact in a mutualism also form a symbiosis, an ecological relationship in which two species live in close contact with one another, including when the smaller species (the symbiont) lives within the cells or body of the larger species (the host). An interaction in which one species benefits and the other is not harmed or helped in any significant way is called commensalism.
In the embryo of a shark, ectoderm gives rise to __________; mesoderm gives rise to __________; endoderm gives rise to __________.
the central nervous system ... muscle ... the lining of the digestive tube
Which of the following was probably the least important factor in bringing about the Cambrian explosion?
the movement of animals onto land.
All animals with bilateral symmetry have __________ germ layer(s).
three; All bilaterally symmetrical animals have three germ layers
Among protostomes, which morphological trait has shown the most variation?
type of body cavity (coelom vs. pseudocoelom vs. no coelom).
Which of the following correctly lists the embryonic stages in the order that they develop?
zygote, blastula, gastrula, larva
totipotency
ability of a cell to direct development of an organism
Gastrulation is the process that directly forms the _____.
primary germ layers
Which of the following is the defining characteristic of the clade Ecdysozoa for which this group is named?
the secretion of stiff external skeletons that must be shed to permit growth; Though named for this characteristic, the clade is actually defined mainly by molecular evidence supporting common ancestry.