Cumulative Final Exam Study Guide PDF

Cumulative Final Exam Study Guide Questions from the cumulative final exam will be drawn from this pool, so I recommend you practice answering them! They may not be identically worded, but they will cover this content. Unit 1: Evolution & microbial life 1. How does evolution explain the unity o...

Cumulative Final Exam Study Guide Questions from the cumulative final exam will be drawn from this pool, so I recommend you practice answering them! They may not be identically worded, but they will cover this content. Unit 1: Evolution & microbial life 1. How does evolution explain the unity of life? How does it explain the diversity of life? Evolution explains the unity of life by highlighting the common ancestry of all organisms. All living organisms share a set of fundamental processes and structures, such as DNA, that trace back to a common ancestor. The diversity of life arises from the accumulation of genetic changes over time, as populations adapt to different environments through mechanisms such as natural selection, mutation, and genetic drift. 2. What are some common misconceptions about the way evolution works? What did the eugenicists of the 20th century get wrong about human evolution? A common misconception is that evolution is a linear progression towards greater complexity or "better" organisms. Evolution does not have a predetermined goal or direction. Eugenicists of the 20th century mistakenly believed that human evolution could be directed by selective breeding to eliminate perceived undesirable traits, failing to understand the complex, multifactorial nature of evolution and genetic inheritance. 3. What are the “four premises” of evolution by natural selection? 1. Variation: Individuals within a population vary in their traits. 2. Inheritance: Some of these variations are heritable and passed on to offspring. 3. Competition: More offspring are produced than can survive, leading to competition for resources. 4. Differential survival and reproduction: Individuals with traits better suited to their environment are more likely to survive and reproduce, passing on those advantageous traits. 4. Where can we find observable evidence for evolution? Observable evidence for evolution can be found in the fossil record, anatomical homologies (similarities in body structure), genetic comparisons (DNA sequences), and observed instances of microevolution, such as changes in population traits over time or the evolution of antibiotic resistance in bacteria. 5. What is the difference between divergent and convergent evolution? What is the difference between a homologous and an analogous trait? Give an example of each. Divergent evolution occurs when two species evolve different traits from a common ancestor (e.g., the forelimbs of mammals). Convergent evolution occurs when two unrelated species evolve similar traits due to similar environmental pressures (e.g., wings of bats and birds). Homologous traits are those that have a common evolutionary origin (e.g., the forelimbs of humans, cats, whales, and bats). Analogous traits are those that serve similar functions but have different evolutionary origins (e.g., the wings of a bat and a butterfly). 6. Describe how natural selection gives rise to adaptations using an example from class or your homework. An example of natural selection leading to an adaptation is the peppered moth in England. In an environment where pollution darkened tree bark, dark-colored moths became more camouflaged and were less likely to be eaten by predators. Over time, the frequency of dark-colored moths increased in the population, demonstrating adaptation through natural selection. 7. What are Mendel’s laws of inheritance? These laws apply only to diploid eukaryotes. Give two examples of organisms that meet this definition.  Mendel's laws of inheritance include the Law of Segregation (each individual has two alleles for each gene, which segregate during gamete formation) and the Law of Independent Assortment (alleles of different genes assort independently of each other). Examples of diploid eukaryotes include humans and pea plants. 8. Define and describe (use a diagram) how these terms are related to each other: gene, genome, chromosome, allele, locus, genotype, phenotype. A gene is a unit of heredity that encodes a protein. A genome is the complete set of genes in an organism. Chromosomes are structures that carry genes and are made of DNA. An allele is a variant form of a gene. A locus is the specific location of a gene on a chromosome. The genotype refers to an organism’s genetic makeup, while the phenotype refers to the observable traits that result from the genotype. 9. What is microevolution? What is macroevolution? How are they related? Microevolution refers to small-scale changes in allele frequencies within a population over time. Macroevolution refers to large-scale evolutionary changes, such as the formation of new species or major changes in body plans. Both microevolution and macroevolution are driven by the same mechanisms (natural selection, genetic drift, etc.), but macroevolution involves the accumulation of microevolutionary changes over long periods. 10. What conditions are required for the gene pool and genetic structure of a population to remain constant over time? Describe each condition in detail and how a violation of this condition would lead to a genetic change over time (hint: review Hardy-Weinberg equilibrium). No mutation: No new alleles are introduced. If mutations occur, genetic variation increases. Random mating: Individuals mate randomly. Non-random mating can lead to allele frequency changes. No natural selection: All individuals have an equal chance of surviving and reproducing. If some individuals are more successful, their alleles will increase in frequency. Large population size: Small populations are more prone to genetic drift, leading to random changes in allele frequencies. No gene flow: No movement of individuals or alleles into or out of the population. Gene flow can introduce new alleles or change allele frequencies. 11. How does sexual reproduction increase the genetic variance of a population? Why would you expect an asexually reproducing population to have lower genetic Diversity? Sexual reproduction introduces genetic diversity through recombination and independent assortment during gamete formation. It also results in offspring with a combination of alleles from two parents, increasing genetic variation. Asexually reproducing populations, by contrast, produce genetically identical offspring (clones), leading to lower genetic diversity. 12. According to the biological species concept... a. Define species and speciation. A species is a group of organisms that can interbreed and produce fertile offspring under natural conditions. Speciation is the process by which new species are formed, typically due to reproductive isolation and genetic divergence. b. What must happen in order for speciation to occur? For speciation to occur, reproductive isolation must first develop, which can be geographic, behavioral, temporal, or mechanical. Over time, genetic differences accumulate, leading to the development of distinct species. 13. What are allopatric and sympatric speciation? How are these types of speciation different? Describe one way a population could undergo allopatric speciation and one way a population could undergo sympatric speciation, including specific reproductive isolating mechanisms (prezygotic vs. postzygotic).  Allopatric speciation occurs when a population is geographically isolated, leading to genetic divergence and the formation of new species. For example, a river might separate a population of animals, leading to reproductive isolation and divergence. Sympatric speciation occurs when new species arise within the same geographic area, often due to behavioral changes, ecological differences, or genetic mutations. Prezygotic isolation mechanisms, like differences in mating behavior, can prevent interbreeding in sympatric speciation, while postzygotic mechanisms, such as hybrid infertility, may reinforce reproductive isolation. 14. How does the fitness of hybrids relative to their parents affect the eventual outcome of a population undergoing speciation? If hybrids have higher fitness than their parents, gene flow between the species may prevent speciation from fully occurring. If hybrids have lower fitness, they may be selected against, and speciation will proceed as parental populations remain distinct. 15. What does a phylogenetic tree represent? What does the length of a branch in a phylogenetic tree represent? A phylogenetic tree represents the evolutionary relationships between different species or groups. The length of a branch can represent the amount of evolutionary change or time that has passed since two species shared a common ancestor. 16. How do scientists construct phylogenetic trees? What information is needed? How do they decide which phylogeny is most likely? Review the phylogenetic trees from lecture and your lab manual, and practice drawing and annotating phylogenetic trees for animals, plants, and fungus. Scientists construct phylogenetic trees using shared derived traits (synapomorphies), molecular data (like DNA sequences), and fossil records. The most likely phylogeny is often determined by the principle of parsimony, which states that the simplest tree (with the least number of evolutionary changes) is the most likely. 17. What is the difference between an ancestral trait and a derived trait? An ancestral trait is a characteristic that was present in a common ancestor of a group, while a derived trait is a characteristic that evolved in a particular lineage after the common ancestor. 18. How does a prokaryotic cell differ in size and structure from eukaryotic cells? What is the relationship between cell complexity and cell size? Prokaryotic cells are smaller and simpler, lacking membrane-bound organelles and a defined nucleus. Eukaryotic cells are larger, more complex, and contain membrane-bound organelles, including a nucleus. Generally, more complex cells tend to be larger because they need space for the organelles and processes that support their functions. 19. How does the genetic material in a prokaryotic cell differ from a eukaryotic cell? Prokaryotic cells have a single, circular chromosome located in the nucleoid region, whereas eukaryotic cells have multiple linear chromosomes located in the nucleus. 20. Do prokaryotes reproduce sexually or asexually? Explain how reproduction and genetic recombination are separate processes in prokaryotes. Name the processes involved in reproduction and genetic recombination. Prokaryotes reproduce asexually through binary fission. Genetic recombination occurs separately through processes like transformation (uptake of DNA from the environment), transduction (DNA transfer by viruses), and conjugation (direct transfer of DNA between cells). 21. Illustrate two examples of primary endosymbiosis that occurred in eukaryotes. a. Label the taxon of the cells involved and the organelles that resulted. Example 1: The ancestor of modern plants engulfed a cyanobacterium, which became the chloroplast. Example 2: An ancestor of modern animals engulfed an aerobic bacterium, which became the mitochondrion. b. Give two pieces of evidence for an endosymbiotic origin that are present in modern cells for each of these examples. Chloroplasts and Mitochondria: Both have their own DNA, separate from the nuclear DNA, and replicate independently via binary fission. Both have a double membrane, which is consistent with engulfment by a host cell. 22. What is a pathogen? Which prokaryotes are sometimes pathogenic? A pathogen is an organism that causes disease. Some prokaryotes, like certain strains of Escherichia coli, Salmonella, and Staphylococcus aureus, can be pathogenic. 23. What characteristics of bacteria allow them to evolve resistance to antibiotics so quickly? Bacteria can evolve resistance rapidly due to their high mutation rates, ability to exchange genetic material through horizontal gene transfer, and short generation times, which allow beneficial mutations to spread quickly. 24.Which groups of prokaryotes contributed to the early evolution and origin of eukaryotes? Why is a phylogenetic tree a misleading depiction of the early evolutionary history of life? The groups Proteobacteria (which contributed to mitochondria) and Cyanobacteria (which contributed to chloroplasts) are believed to have contributed to the origin of eukaryotes. A phylogenetic tree can be misleading because early evolutionary events, such as endosymbiosis, involved complex interactions between different lineages, making a simple branching tree difficult to interpret. 25. What are protists? Explain why protists do not form a monophyletic group. Protists are a diverse group of eukaryotic organisms that do not fit into the plant, animal, or fungal kingdoms. They do not form a monophyletic group because they do not share a single common ancestor; instead, they represent multiple evolutionary lineages. 26. Compare the size and complexity of the cells of prokaryotes, microbial eukaryotes and multicellular eukaryotes. Prokaryotic cells are small and simple, with no membrane-bound organelles. Microbial eukaryotes are larger and more complex, with organelles like nuclei and mitochondria. Multicellular eukaryotes have specialized cells, tissues, and organs, with even more complexity in terms of cell types and functions. 27. Several protist groups are called “algae”. What are “algae”? Name the 3 distinct major groups of algae. Are they monophyletic? What role do algae play in ecosystems? Algae are photosynthetic protists that live in aquatic environments. The three major groups are green algae, red algae, and brown algae. These groups are not monophyletic, as they evolved photosynthesis independently. Algae play a crucial role in ecosystems by producing oxygen and serving as the base of aquatic food webs. Unit 2: Plants & fungi 1. What are meristematic and permanent plant tissues? How are they different? Where are they found on the plant body? Meristematic tissues are regions of actively dividing cells responsible for growth (e.g., apical meristems at tips of roots and stems). Permanent tissues are formed when meristematic cells differentiate into specialized cells (e.g., vascular tissues like xylem and phloem). 2. How does a vascular system enable leaves and roots to function together in supporting the life and growth of the plant? The vascular system, composed of xylem and phloem, transports water, nutrients, and sugars between roots and leaves, allowing for efficient resource distribution necessary for growth and survival. 3. Plants have indeterminate growth. Explain what this means and how they accomplish It. Indeterminate growth means that plants can grow throughout their life. This is accomplished through meristems, where cells continuously divide and elongate. 4. What is secondary growth? Which plants have secondary growth? How is secondary growth beneficial to the plants that have it? Secondary growth is the increase in girth of plants due to the activity of the vascular cambium and cork cambium. It occurs in woody plants (e.g., trees and shrubs), providing strength and the ability to transport more water and nutrients. 5. What is a photoautotroph and how does it differ from a heterotroph? Which organisms fall into each category? Photoautotrophs use sunlight to make their own food (e.g., plants, algae). Heterotrophs consume other organisms for energy (e.g., animals, fungi). 6. Why is photosynthesis essential for life on Earth? Photosynthesis produces oxygen and organic molecules (such as glucose), which are essential for the survival of most organisms on Earth. 7. Where does photosynthesis occur in plants? Which organs? Which tissues? Which cells? What part of the cell? Photosynthesis occurs primarily in the leaves of plants, within the mesophyll tissue. The cells that perform photosynthesis are chloroplasts, which contain chlorophyll. 8. Explain in general terms how photosynthesis works. You do not need to describe specific molecules. Photosynthesis converts light energy into chemical energy, producing glucose and oxygen by using sunlight, carbon dioxide, and water. This process involves two main stages: light reactions (which capture light energy) and the Calvin cycle (which synthesizes glucose). 9. What is a seed? What stages of a plant’s life cycle are present in a seed and which parts of the seed do they form? What is pollen? What stages of a plant’s life cycle develop from a pollen grain? A seed contains the embryo (a young plant), the stored nutrients (endosperm), and a protective seed coat. Pollen is a male gametophyte that contains the sperm, which fertilizes the ovule (female gametophyte), leading to the formation of a seed. 10. How have mutualistic relationships with animals affected the diversity of angiosperm fruits and flowers? Describe two different examples of both pollination and dispersal. Mutualistic relationships have led to a wide variety of specialized flower and fruit types. For example, bee-pollinated flowers tend to be brightly colored and fragrant, while wind-pollinated flowers are small and inconspicuous. Bird-dispersed fruits are often brightly colored and fleshy, while wind-dispersed fruits are lightweight and have wings. a. How might you expect a wind-pollinated flower to differ from a bee-pollinated flower? b. How might you expect a wind-dispersed fruit to differ from a bird-dispersed fruit? 11. What is the function of endosperm in an angiosperm’s seeds? What unique feature of plant reproduction produces endosperm? Endosperm provides nutrients to the developing embryo. It forms through a process called double fertilization, where one sperm cell fuses with the egg cell to form the zygote, and another sperm cell fuses with two polar nuclei to form the endosperm. 12. What is the primary function of an angiosperm’s fruits? Describe examples of adaptations for each of these functions. The primary function of fruit is to protect and disperse seeds. Adaptations for dispersal include fleshy fruits for animal consumption, winged fruits for wind dispersal, and barbed fruits for attachment to animal fur. 13. How are extant vascular plants morphologically different from nonvascular plants? Describe differences in the leaves, reproductive organs, and structures involved in the transportation of water and nutrients. Which of these differences explains why we call these plants “vascular”? Vascular plants have specialized tissues (xylem and phloem) for transporting water and nutrients, whereas nonvascular plants rely on diffusion. Vascular plants also have larger, more complex leaves and reproductive organs like seeds or spores, while nonvascular plants have simple, small leaves and require water for reproduction. 14. Name the two groups of seed plants. What traits differentiate them? Which evolved first? Which is more diverse? The two groups of seed plants are gymnosperms and angiosperms. Gymnosperms (e.g., conifers, cycads) are seed plants whose seeds are exposed or held in cones. They have needle-like leaves, and most are adapted to dry conditions. Gymnosperms evolved first, about 300 million years ago. Angiosperms (flowering plants) have seeds enclosed within a fruit and are characterized by flowers, which aid in pollination. Angiosperms are more diverse and widespread than gymnosperms, with over 250,000 species compared to about 1,000 species of gymnosperms. 15. How can you tell a monocot apart from a eudicot? Monocots: ○ Have one cotyledon (seed leaf). ○ Parallel-veined leaves. ○ Flower parts in multiples of three. ○ Vascular bundles are scattered throughout the stem. ○ Example: Grasses, lilies. Eudicots: ○ Have two cotyledons. ○ Branched or net-like venation in leaves. ○ Flower parts in multiples of four or five. ○ Vascular bundles form a ring in the stem. ○ Example: Roses, sunflowers. 16. Compare and contrast the general body plan and growth of fungi and plants. Fungi: Fungi are composed of a network of hyphae that form the mycelium. They do not have leaves, stems, or roots like plants. Fungi grow by extending their hyphae and spreading across the substrate. They are non-photosynthetic and absorb nutrients through external digestion. Plants: Plants have a defined body plan with roots, stems, and leaves. They grow by cell division in meristems (e.g., apical meristems for length, lateral meristems for girth).  Plants are photosynthetic and produce their own energy through sunlight. They use vascular tissue (xylem and phloem) for internal transport of water, nutrients, and sugars. 17. How do fungi obtain and store energy? How is this similar to and different from animals and plants? Fungi: Fungi obtain energy by breaking down organic matter through external digestion (absorptive heterotrophy). They secrete enzymes that break down complex organic materials into simpler compounds that can be absorbed. Animals: Animals also obtain energy by ingesting and digesting food (heterotrophy), but unlike fungi, they do not secrete enzymes externally and instead digest food internally. Plants: Plants are autotrophic and obtain energy by photosynthesis. They store energy in the form of starch (a polysaccharide), which they synthesize from glucose produced during photosynthesis. 18. What are spores? How are they produced? Spores are reproductive cells that can develop into a new organism without fertilization. They are typically haploid (single set of chromosomes) and are produced by both sexual and asexual reproduction in fungi, plants, and some protists. In fungi, spores are produced through both sexual and asexual processes. Asexual spores (e.g., conidia, sporangia) are produced in structures like sporangia or conidiophores. Sexual spores (e.g., ascospores, basidiospores) form during sexual reproduction when gametes fuse. 19. What are mushrooms? Which groups of fungi produce mushrooms? What life cycle stage do mushrooms represent? Mushrooms are the fruiting bodies of certain fungi, specifically basidiomycetes. They are the reproductive organs of the fungi, where spores are produced. ○ Mushrooms are produced by basidiomycetes (e.g., club fungi, including common mushrooms) and some ascomycetes. ○ Mushrooms represent the sexual reproductive stage in the fungal life cycle. They produce basidiospores (in basidiomycetes) or ascospores (in ascomycetes) that will be dispersed to form new fungal individuals. 20. Why are fungi well-adapted to function as decomposers in ecosystems? Describe at least two traits in your explanation. External Digestion: Fungi secrete enzymes that break down complex organic matter (such as cellulose and lignin) into simpler compounds. This allows them to decompose dead plant and animal material and recycle nutrients into the ecosystem. Hyphal Network: Fungi grow as extensive networks of hyphae that spread through decomposing material. This large surface area allows them to absorb nutrients efficiently from a wide area. 21. What do the terms “yeast” and “mold” refer to? Yeast refers to unicellular fungi that typically reproduce by budding or fission. Yeasts are often used in baking and brewing because of their ability to ferment sugars. Mold refers to multicellular fungi that grow in a filamentous, branching structure (mycelium). Molds reproduce by producing spores and are often seen as fuzzy growths on food or decaying matter. 22. Many fungi form symbioses with plants or animals. Explain what this means and give an example of a mutualistic symbiosis and a parasitic symbiosis. Mutualistic symbiosis: Both organisms benefit. Example: Mycorrhizae, where fungi form a mutualistic relationship with plant roots, aiding nutrient absorption for the plant while receiving sugars from the plant. Parasitic symbiosis: One organism benefits at the expense of the other. Example: Athlete's foot fungus (a parasitic fungus) infects human skin, causing discomfort and damage while benefiting from the nutrients in the skin. 23. What are mycorrhizae? Which groups of fungi are involved in mycorrhizae? Why do you think that most plants form mycorrhizae? Mycorrhizae are symbiotic relationships between fungi and plant roots. The fungi help plants by improving their uptake of water and essential nutrients (especially phosphorus), while the plants provide the fungi with organic carbon (sugars) produced through photosynthesis. The major groups of fungi involved in mycorrhizae are Glomeromycota (arbuscular mycorrhizae) and Basidiomycota (ectomycorrhizae). Most plants form mycorrhizae because they provide a means of accessing nutrients in soil that are otherwise difficult to absorb, particularly in nutrient-poor soils. This mutualistic relationship enhances plant growth and survival. Unit 3: Animals 1. Why are surfaces in animal bodies that are used for exchanging materials between two systems (or between external and internal environments) often highly branched or folded? Give two examples of exchange surfaces in animals bodies and describe how their structure is related to their function. Surfaces used for material exchange are often highly branched or folded to increase their surface area, which maximizes the area available for diffusion of gases, nutrients, or wastes. This facilitates more efficient exchange. Example 1: Alveoli in the lungs: The alveoli are tiny, sac-like structures with a large surface area due to their branching. This allows for efficient gas exchange between the lungs and the blood. Example 2: Villi in the small intestine: Villi are finger-like projections in the intestines that increase surface area for nutrient absorption from digested food into the bloodstream. 2. Can all animals reproduce asexually? Is asexual reproduction common among animals? When might asexual reproduction be advantageous? Not all animals reproduce asexually, but some do. Asexual reproduction is more common in invertebrates like cnidarians (e.g., hydras) and echinoderms (e.g., starfish). Asexual reproduction can be advantageous when: Population growth is needed quickly, as it doesn’t require a mate. Stable environments: In environments where conditions are not changing rapidly, asexual reproduction can preserve successful genetic traits. Less energy investment: There is no need to find a mate or invest in mating behaviors. 3. What is homeostasis? Why is homeostasis important for animals? Use a diagram to explain how negative feedback is involved in thermal homeostasis (aka thermoregulation). Include the concept of a set point and specific mechanisms that raise or lower body temperature in a mammal. Homeostasis is the process by which an organism maintains a stable internal environment, despite external changes. This is important for optimal functioning of the body's systems. Thermal homeostasis (thermoregulation) is an example of homeostasis where animals regulate their body temperature. Set point: The body’s target temperature, typically around 37°C (98.6°F) in humans. Negative feedback mechanism: If body temperature deviates from the set point: ○ If too high: Sweating or vasodilation (blood vessels dilate) helps release heat. ○ If too low: Shivering or vasoconstriction (blood vessels constrict) helps conserve heat. (Diagram: Thermoregulation with feedback loop: sensors → control center → effectors → response) 4. How is the ratio of an animal's surface area to its volume related to the rate of heat exchange? How does body size affect thermoregulation through heat conservation and dissipation? The surface area-to-volume ratio determines how quickly heat is exchanged between an organism and its environment. Larger surface area allows for more heat exchange, which is why small animals lose heat quickly. Smaller body size means greater heat loss relative to volume, while larger animals have a smaller surface area relative to their volume, meaning they lose heat more slowly and can conserve heat better. Smaller animals (e.g., mice) need to generate more heat to maintain body temperature, while larger animals (e.g., elephants) have better heat conservation abilities. 5. Which vertebrates are always homeotherms? Are these animals ectothermic or endothermic? What morphological adaptations do these animals use for insulation? Birds and mammals are always homeotherms (they maintain a constant body temperature). These animals are endothermic (they generate heat internally through metabolism). Morphological adaptations for insulation: ○ Feathers in birds and fur in mammals trap heat. ○ Blubber in marine mammals helps insulate against cold temperatures. ○ Fat deposits also act as insulation to conserve body heat. 6. What morphological traits have traditionally been used to classify animals? Use a phylogeny or flow chart to describe the major classification of animals on the basis of these traits. Traditional morphological traits used to classify animals include: ○ Symmetry: Asymmetry, radial symmetry, and bilateral symmetry. ○ Germ layers: Diploblastic (two germ layers) vs. triploblastic (three germ layers). ○ Body cavity: Coelom (body cavity) vs. acoelomate (no body cavity). ○ Presence of a notochord: Chordates. ○ Segmentation: Present or absent. (Flowchart: Symmetry → Germ Layers → Coelom → Segmentation → Phylum) 7. Some animals are diploblasts and some are triploblasts. Define these terms, and identify which category contains organisms that have a coelom. Then define what a coelom is and the purpose it serves in eucoelomate animals. Diploblasts: Animals that develop two germ layers: ectoderm and endoderm (e.g., cnidarians like jellyfish). Triploblasts: Animals that develop three germ layers: ectoderm, mesoderm, and endoderm (e.g., most animals, including humans). Coelom: A body cavity between the mesoderm and endoderm in triploblastic animals. Eucoelomate animals have a true coelom, which allows for more complex organ systems and better mobility of organs within the body. 8. Name and describe the two main types of symmetry found in animal body plans and describe an advantage of each type of symmetry. Give examples of animals with each type of symmetry. Radial symmetry: Body parts are arranged around a central axis (e.g., sea stars, jellyfish). This symmetry is advantageous for stationary or slow-moving animals, as it allows them to interact with their environment from all directions.  Bilateral symmetry: The body is divided into two mirrored halves along one plane (e.g., humans, fish). This symmetry is advantageous for directional movement, allowing for better coordination and more efficient locomotion. 9. What is cephalization? Which type of symmetry is associated with cephalization? Name one advantage of cephalization. Cephalization is the concentration of sensory and nervous tissues in the head region, forming a distinct head with sensory organs and a brain. ○ Bilateral symmetry is associated with cephalization because it allows for a distinct anterior (front) end. ○ Advantage: It enables more efficient processing of sensory information and coordination of movement, particularly for directional travel. 10. What are the three most diverse animal phyla? The three most diverse animal phyla are: ○ Arthropoda (insects, spiders, crustaceans) - Highly diverse in body forms and adaptations. ○ Mollusca (snails, clams, squids) - Includes soft-bodied animals, many with shells. ○ Chordata (vertebrates like mammals, birds, fish) - Includes animals with a notochord, spinal cord, and gill slits at some stage of development. 11. Name the phylum that contains each of these animals and list the traits that distinguish organisms in this phylum from other phyla. a. Sponges Phylum Porifera. They lack tissues and organs, have porous bodies, and filter feed by drawing water through pores. b. anemones and jellies Phylum Cnidaria. They have radial symmetry, a simple digestive cavity, and specialized stinging cells (cnidocytes). c. gastropods, cephalopods and bivalves Phylum Mollusca. They have soft bodies, often with shells, and a mantle. d. Earthworms Phylum Annelida. They have segmented bodies, a coelom, and a closed circulatory system. e. crustaceans, arachnids and insects Phylum Arthropoda. They have exoskeletons, segmented bodies, and jointed appendages. f. sea stars and sea urchins Phylum Echinodermata. They have radial symmetry as adults and a water vascular system. g. lancelets and tunicates Phylum Chordata. They possess a notochord, dorsal hollow nerve cord, and pharyngeal slits at some stage of development. 12. Is the closed circulatory system of annelids homologous to the closed circulatory system of cephalopods? Explain. Yes, the closed circulatory systems of annelids (e.g., earthworms) and cephalopods (e.g., squids, octopuses) are homologous because both systems use blood vessels to transport blood. However, the systems are structurally different, with cephalopods having more advanced circulatory adaptations due to their larger size and higher metabolic demands. 13. What are shared derived traits of arthropods? How did these traits facilitate their diversification into a wide variety of specialized body forms? Shared derived traits of arthropods include: Exoskeleton made of chitin for protection and support. Segmented body and jointed appendages for flexibility and specialized functions. Specialized respiratory systems (e.g., gills in aquatic forms, tracheae in terrestrial forms). These traits allowed arthropods to colonize diverse environments, from aquatic to terrestrial habitats, and specialize in different niches. 14. What are the four defining characteristics of chordates? Notochord: A flexible rod that provides support. Dorsal hollow nerve cord: Develops into the brain and spinal cord. Pharyngeal slits: Used for filter feeding or respiration. Post-anal tail: Extends beyond the anus and is used for movement in many species. 15. Describe the major morphological trait that differentiates vertebrates from invertebrate chordates. What genetic changes accompanied these physical changes? Vertebrates have a vertebral column (backbone) made of vertebrae, which replaces the notochord as the primary structural support. Invertebrate chordates lack a vertebral column. Genetic changes associated with the evolution of vertebrates include the development of genes involved in the formation of the vertebral column and the central nervous system. 16. What structural changes in the tetrapod skeleton accompanied the evolution of four limbs and a transition to land? The evolution of tetrapods involved the modification of fins into limbs with stronger, weight-bearing bones. Changes include the development of limb girdles (pelvic and pectoral) to support weight on land, and the modification of the spinal column to support the body against gravity. 17. How do reptiles and amphibians differ? How do these differences explain their different habitat requirements? Reptiles: Have scaly skin, lay amniotic eggs, and are typically more resistant to water loss. This allows them to live in drier environments. Amphibians: Have moist skin, lay eggs in water, and often need water for reproduction, making them reliant on moist environments. 18. Which vertebrates are amniotes? What adaptation are amniotes named for? How was this an adaptation for a fully terrestrial lifestyle? In placental mammals, how do the extraembryonic membranes function? Amniotes include reptiles, birds, and mammals.  ○ Amniotes are named for the amniotic egg, which contains protective membranes that prevent desiccation and allow for reproduction in dry environments. ○ In placental mammals, the extraembryonic membranes (amniotic sac, chorion, yolk sac, and allantois) provide protection, nutrients, and waste removal for the developing embryo. 19. What shared derived trait are mammals named for? Describe three other traits that distinguish them from other vertebrates. Mammals are named for the presence of mammary glands, which produce milk for feeding young. Other distinguishing traits include: ○ Hair or fur for insulation. ○ Three middle ear bones for hearing. ○ Endothermy: the ability to regulate body temperature internally. 20. What traits differentiate primates from other mammals? How are (some of) these traits adaptive for an arboreal lifestyle? Traits that differentiate primates include: Grasping hands and feet with opposable thumbs. Forward-facing eyes for depth perception. Large brains relative to body size. These traits are adaptive for an arboreal lifestyle (living in trees), helping with grasping branches, moving efficiently through trees, and better visual coordination. 21. When and where did Homo sapiens first evolve? When did Homo sapiens last share a common ancestor with chimpanzees? Homo sapiens first evolved in Africa about 300,000 years ago. Homo sapiens last shared a common ancestor with chimpanzees around 6 to 7 million years ago. Summative Questions These questions are based on multiple prior units. 1. All life shares a few key properties. Name and explain three of these properties using specific examples from what we have learned about plants, animals or fungi. Cellular organization: All life is made up of cells, the basic units of structure and function. In plants, parenchyma cells are responsible for photosynthesis, while in animals, muscle cells allow movement. In fungi, hyphal cells form networks that absorb nutrients. Energy utilization: All living organisms acquire and utilize energy to fuel their metabolism. Plants use photosynthesis to convert sunlight into chemical energy. Animals, such as humans, obtain energy by consuming other organisms (heterotrophs). Fungi, like mushrooms, absorb nutrients from decomposing organic matter (saprotrophic nutrition). Reproduction: All life forms reproduce to pass on their genetic information. Plants can reproduce sexually through flowers (e.g., the pollen and ovule system), animals can reproduce sexually (e.g., fertilization in mammals), and fungi can reproduce both sexually (e.g., the fusion of spores) and asexually (e.g., spore production in mushrooms). 2. Describe how the sexual life cycles of animals, plants and fungi are similar and different using three labeled diagrams. Diagrams should include major life stages (& their ploidy) as well as the processes involved in the transition between life stages. Animals: Animals undergo sexual reproduction with gametes (sperm and egg) that are haploid. After fertilization, a diploid zygote forms, which grows into an adult organism through mitosis. Diagram: Gametes (haploid) → Fertilization → Zygote (diploid) → Mitosis → Adult (diploid) Plants: Plants also have a haploid gametophyte stage and a diploid sporophyte stage. Fertilization leads to a diploid zygote, which grows into a sporophyte. The sporophyte produces haploid spores through meiosis, starting the cycle again. Diagram: Gametes (haploid) → Fertilization → Zygote (diploid) → Sporophyte (diploid) → Meiosis → Spores (haploid) Fungi: Fungi typically alternate between haploid and dikaryotic stages. After fertilization, karyogamy occurs, forming a diploid zygote. Meiosis then produces haploid spores, which germinate into new fungal individuals. Diagram: Haploid mycelium → Plasmogamy → Dikaryotic stage → Karyogamy → Zygote (diploid) → Meiosis → Spores (haploid) 3. Describe how energy acquisition and storage differs between animals, plants and fungi. Animals: Animals are heterotrophic, meaning they must consume other organisms for energy. They store energy in the form of glycogen (in animals) and lipids (fat). Plants: Plants are autotrophic, using photosynthesis to produce their own energy by converting sunlight into glucose. They store energy primarily in the form of starch. Fungi: Fungi are heterotrophic like animals, but they acquire energy by breaking down organic material externally through extracellular digestion. They store energy as glycogen, similar to animals. 4. Which groups of organisms are multicellular? Is multicellularity in these groups a homologous or analogous trait? Explain using a phylogenetic tree. The multicellularity in animals, plants, and fungi is an analogous trait because these groups evolved multicellularity independently, despite having a common eukaryotic ancestor. In a phylogenetic tree, animals, plants, and fungi would be shown as separate branches from a common eukaryotic root, indicating independent evolution of multicellularity in each group. 5. Life began in the ocean and has moved onto land in multiple distinct events over the course of evolutionary history. Describe the advantages and disadvantages plants and animals faced when they moved onto land, and how each group adapted to meet these challenges. Plants: Advantages: Access to more sunlight and carbon dioxide for photosynthesis, less competition for resources.  Disadvantages: Desiccation (drying out), structural support, reproduction (gametes need to find each other in the air). Adaptations: ○ Cuticle to prevent water loss. ○ Vascular tissues (xylem and phloem) to transport water and nutrients. ○ Pollen to transport gametes through air and seeds for reproduction without water. Animals: Advantages: New habitats to exploit, access to more food resources, fewer predators at first. Disadvantages: Desiccation, gravity, and oxygen availability. Adaptations: ○ Waterproof skin or exoskeletons to prevent water loss (e.g., reptiles' scales). ○ Lungs for breathing air. ○ Limbs for movement on land (e.g., tetrapod evolution). 6. The amniote egg and the plant seed independently evolved to solve a similar problem. Describe the problem they solved, and name the taxon organisms in which each structure first emerged. Problem solved: Both the amniote egg and the plant seed evolved to prevent desiccation and protect the developing embryo in a dry, terrestrial environment. Amniote egg: First emerged in reptiles, solving the problem of water loss during reproduction. It includes protective membranes, a shell, and a nutrient-rich yolk for the developing embryo. Plant seed: First emerged in seed plants (angiosperms and gymnosperms) and serves a similar purpose by providing a protective coat and nourishment for the developing embryo. 7. Compare and contrast the structure of cells, tissues and organs and organ systems in plants, animals and fungi. How is the hierarchical organization of their bodies similar and different? Cells: Plants: Plant cells have cell walls, chloroplasts, and large vacuoles for storage and support. Animals: Animal cells have a plasma membrane, no cell wall, and small vacuoles.  Fungi: Fungal cells have cell walls made of chitin, and vacuoles for storage. Tissues: Plants: Plant tissues include vascular tissue (xylem and phloem), ground tissue, and dermal tissue. Animals: Animal tissues include muscle, epithelial, connective, and nervous tissue. Fungi: Fungal tissues consist of hyphae, forming mycelium that absorbs nutrients. Organs and Organ Systems: Plants: Organ systems include roots, stems, and leaves. There are no complex organ systems like in animals. Animals: Complex organ systems such as the digestive, circulatory, and nervous systems allow for specialized functions. Fungi: Fungal bodies are mostly composed of hyphae, and some, like mushrooms, have specialized reproductive structures (spores). 8. How are cell and body size constrained by diffusion? Explain how this sets an upper limit on the body size of unicellular organisms. Explain how this sets an upper limit on the body size of multicellular organisms that lack vascular systems. Unicellular organisms: The size of unicellular organisms is limited because diffusion is the primary method for nutrient and waste exchange. As the cell size increases, diffusion becomes inefficient, limiting the size of the organism. Multicellular organisms without vascular systems: For multicellular organisms that lack vascular systems (e.g., simple animals like flatworms), the size is also constrained because cells further from the surface cannot efficiently exchange gases and nutrients via diffusion. This limits the organism's size, as all cells need to be close to the surface for diffusion to work. 9. Humans are... (choose ALL terms that apply): PROKARYOTES / EUKARYOTES / PROTISTS / OPISTHOKONTS / PLANTAE / EMBRYOPHYTES / METAZOANS / BILATERIA / PROTOSTOMES / ECDYSOZOANS / LOPHOTROCHOZOANS / ECHINODERMS / DEUTEROSTOMES / EUCOELOMATES / ACOELOMATES / CHORDATES / TUNICATES / INVERTEBRATES / VERTEBRATES / GNATHOSTOMES / AGNATHANS / AMPHIBIANS / TETRAPODS / AMNIOTES / DIAPSIDS / SYNAPSIDS / MAMMALS / EUTHERIANS / MONOTREMES / MARSUPIALS / PRIMATES / APES / HOMININS ○ Eukaryotes ○ Metazoans ○ Bilateral ○ Deuterostomes ○ Eucoelomates ○ Chordates ○ Vertebrates ○ Gnathostomes ○ Amniotes ○ Synapsids ○ Mammals ○ Eutherians ○ Primates ○ Apes ○ Hominins