bio 116 exam 4 Questions and Answers

bio 116 exam 4 Questions and Answers In animal development, which of the following best describes the process of cleavage? - Ans:- Mitosis What are the cells created by cleavage called? - Ans:-Blastomeres Which of the following are the three germ layers contained in the gastrula? - Ans:-Ectoderm, mesoderm, endoderm Which of the following stages of development is defined by the three embryonic tissue layers (ectoderm, mesoderm, and endoderm)? - Ans:-Gastrula What happens to a cell during the process of differentiation? - Ans:-It undergoes a change toward a more specialized form or function. A child is born without a fully developed pancreas. He is normal in all other respects, and thus doctors believe that the problem most likely began early in development. During which of the following processes did the original error most likely occur? - Ans:-Endoderm formation ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/76 True or false? Early animal development progresses through distinct stages: first the production of the zygote through fertilization, then cleavage, then the formation of the gastrula, and then the formation of the blastula. - Ans:-false After fertilization, embryonic development progresses through three stages: cleavage, during which the zygote develops into a blastula through extensive cell division; gastrulation, during which three tissue layers are established by the dramatic rearrangement of cells, forming a gastrula; organogenesis, during which the rudiments of organs develop. The details of embryonic development vary by species, but the developmental sequence is consistent. Embryonic development has been studied extensively in a few species, including sea urchins, frogs, and chickens. All the images in this tutorial are based on frog development. Part A - Differentiating between cleavage, gastrulation, and organogenesisPart complete Determine which terms, phrases, and images describe each phase of development. Drag each item to the appropriate bin. - Ans:-cleavage: -blastula ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/76 -cytoplasm partitioned into many cells -picture without the layers gastrulation: -embryonic germlayers form -blastopore -gastrula -colorful picture organogenesis: -neural tube -organs begin to develop from germ layers -somites Part B - Gastrulation in a frog embryoPart complete ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/76 Gastrulation is the stage of embryonic development following cleavage. During gastrulation, cell division slows dramatically, and cells are rearranged in a precise way, forming three germ layers. The diagram below illustrates gastrulation in a frog embryo, represented in cross section. Drag the labels to their appropriate locations on the diagram. Use only pink labels for pink targets. Not all labels will be used. - Ans:-A. blastocoel B. primitive gut (archenteron) C. ectoderm D. mesoderm E. endoderm F. blastopore G. yolk plug H. blastopore forms I. primitive gut begins to form J. three germ layers in place Part C - Organogenesis in a frog embryoPart complete Tissue and organ formation begins during the process of organogenesis. ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 5/76 Which five of the following statements are true about organogenesis in a frog embryo? - Ans:--The notochord does not persist in adult frogs. -The neural tube forms from ectoderm and develops into the central nervous system. -Somites form along the length of the notochord and neural tube. -The endoderm gives rise to the lining of the frog's digestive tract. -Some somite cells migrate to other locations in the developing embryo. In sea urchins, the process of fertilization produces a(n) _____. - Ans:-zygote What is the cortical reaction? - Ans:-the formation of a fertilization envelope that bars additional sperm from entry into the egg As cleavage continues, a zygote forms into a solid multicellular ball called a(n) _____. - Ans:-morula Several hours after fertilization, cleavage results in the formation of a hollow ball of cells called a _____. - Ans:-blastula The three-layered embryo is the _____. - Ans:-gastrula The _____ eventually develops into the sea urchin's digestive tract. - Ans:-archenteron During gastrulation, invagination occurs at the _____. - Ans:-blastopore ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 6/76 In vertebrates, the ectoderm gives rise to the _____. - Ans:-outer layer of skin In an embryonic vertebrate, the zone of polarizing activity (ZPA) is a block of tissue located on the posterior side of a limb bud. The ZPA provides information about the anterior-posterior axis of the limb. Cells nearest the ZPA form the most posterior of digits (like our little finger); cells farthest from the ZPA form the most anterior digits (like our thumb). How would a vertebrate forelimb bud develop if it had two zones of polarizing activities, one on the posterior side and one on the anterior side of the bud? - Ans:-The forelimb bud would develop with extra digits, in a mirror image arrangement to the normal digits. In an embryonic vertebrate, the apical ectodermal ridge (AER) is a thickened area at the tip of the bud. The cells of the AER secrete protein signals that promote limb-bud outgrowth, and removing the AER blocks growth of the limb along the proximal-distal axis. How would the forelimb of an embryo develop if the AER was removed early or late in limb development? - Ans:-Early removal of the AER would prevent the formation of many distal structures, whereas late removal of the AER would prevent the formation of a few distal structures. During gastrulation in frogs, a rod of mesoderm under the dorsal surface forms the _____. - Ans:- notochord During gastrulation in frogs, cells from the animal pole spread over the embryo and form the _____. - Ans:-ectoderm ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 7/76 The notochord functions as a core around which mesodermal cells form the frog's _____. - Ans:- backbone An ectodermal thickening above the frog's notochord forms a _____. - Ans:-neural plate The _____ is(are) formed when the neural folds join and a portion of the neural plate sinks beneath the embryo's surface. - Ans:-neural tube The enlarged anterior portion of the neural tube will develop into a frog's _____. - Ans:-brain The posterior portion of the neural tube will develop into the frog's _____. - Ans:-spinal cord The energy that flows through most ecosystems comes from the sun. Primary producers convert a fraction of the sun's energy into chemical energy, which can be used by consumers. Food webs describe how energy flows between trophic levels in an ecosystem, and a trophic pyramid represents the amount of energy available at each trophic level. Part A - Identifying trophic levels in a food web Use the following diagram of a food web to sort the items below. Drag each label to the appropriate bin. If an organism is both a secondary consumer and a tertiary consumer, drag it to the "both secondary and tertiary consumer" bin. - Ans:-Detritus: -rotting log ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 8/76 -dead animal Primary producer: -living maple leaves Primary consumer or decomposer: -cricket -fungus -maggots Secondary consumer: -millipede -earthworm Both secondary and tertiary consumer: ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 9/76 -alligator lizard -robin Part B - Calculating trophic efficiencyPart complete Calculate the trophic efficiency from each trophic level to the next for the pyramid of productivity (biomass pyramid) shown below. Express your answers numerically as percents, but do not add percent symbols (%). Enter your three answers separated by commas in the order a, b, c - Ans:-15.0,11.0,12.0 Part C - Analyzing energy flowPart complete Which of the following statements about energy flow are true? Select the four statements that are true. - Ans:--If the lowest trophic level of an ecosystem--the primary producers--contains 1,200 grams of biomass per square meter, it is reasonable to expect the secondary consumer level to contain about 12 grams of biomass per square meter. -Animals that produce their own body heat and maintain a high body temperatu