BIOL 122 Exam 3 Study Guide Fall 2024 PDF

Chapter 11 Describe Darwin’s theory of evolution by natural selection. How did his travels around the world influence the development of this idea? what were his 4 postulates of natural selection? Darwin proposed that the mechanism of evolution occurs through natural selection (which...

Chapter 11 Describe Darwin’s theory of evolution by natural selection. How did his travels around the world influence the development of this idea? what were his 4 postulates of natural selection? Darwin proposed that the mechanism of evolution occurs through natural selection (which causes populations to adapt or become increasingly better suited to their environment over time). During his voyage on the Beagle, he observed the diversity of species and their adaptations in places like the Galapagos Islands, which influenced his ideas about natural selection. Variation: Individuals within a population vary. Heredity: Variations are heritable. Overproduction: More individuals are born than can survive. Differential success: Individuals with advantageous characteristics are more likely to reproduce. What is natural selection? What is artificial selection? Natural selection: Nature favors traits that are beneficial for survival. Artificial selection: Humans select for desired traits, such as in domesticated animals. Describe how Lamarck’s mechanism of evolution is different from Darwin’s. Define evolution. Lamarck: Creía que los organismos adquieren características por uso y desuso durante su vida y las heredan (ej., jirafas estirando sus cuellos). Darwin: Propuso que la selección natural favorece variaciones heredables que aumentan la supervivencia y reproducción. Evolución: Es el cambio en las características heredables de una población a lo largo del tiempo. What is the difference between microevolution and macroevolution? Microevolution: Small changes in a population over generations (e.g., allele frequencies). Macroevolution: Large changes that result in new species.  What are the 3 requirements for evolution, and what does each really mean? What is a population? Variability: Es decir que en una población existan diferencias geneticas Heritability: Las caracteristicas se puedan transmitir a su descendencia Differential Reproductive Success: Los individuos con diferentes características producen diferentes cantidades de crías que sobreviven y se reproducen. Population: A group of organisms of the same species that live in the same geographic area and are capable of breeding with each other Describe the work of Peter and Rosemary Grant on the medium ground finch in the Galapagos. How does this long-term study illustrate the principles of natural selection? El trabajo de ellos se baso en el estudio de los picos de las aves el cual evoluciono rapidamente en respuesta a cambios en medio ambiente como las sequias, se desucrbio que los picos grandes eran mas ventajosos en tiempos de sequias y los picos pequenos eran mas ventajosos en epocas humedas. Su trabajo demuestra que la selección natural puede actuar en cortos periodos de tiempo, impulsando cambios adaptativos según las condiciones ambientales. Define convergent evolution, and homologous vs. analogous structures. How would we know whether a trait is homologous or analogous? (also see chp 12) Convergent evolution: Occurs when organisms that aren't closely related evolve similar features or behaviors, often as solutions to the same problems. Homologous Structure: An organ, system, or body part that shares a common ancestry in multiple organisms. Analogous Structure: Analogous structures are features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature.  In addition to natural selection, what are the 4 evolutionary mechanisms that change populations over time?Explain how each works. Mutation: Changes in the DNA that can introduce new genetic variations, this variation are neutral or harmful in the most of the cases but can be positive also, providing advantages. Gene Flow: The transfer of traits (rasgos) in or out of a population, individuals from one population migrate to another and reproduce, they introduce new genetic variants or change the frequencies of existing alleles. This tends to increase genetic diversity within a population and reduce genetic differences between populations. Genetic Drift: Random changes in the allele frequencies, due to random events like natural disasters. Nonrandom Mating: Occurs when individuals choose mates with particular phenotypes instead of random mates What is an allele v. a gene pool? An allele is a specific version or variant of a gen and the gene pool refers to the collective set of all alleles present within a population of a species. What is an adaptation? A favored trait (rasgo favorecido) that spreads through a population by natural selection.(cuello de las jirafas) What is sexual selection and why does it result in sexual dimorphism (and what does this term mean)? Sexual selection is nonrandom mating that favors traits that increase the chances of reproduction, but reduce its chances of survival. (habilidad de atraer al sexo opuesto gracias a ciertos rasgos geneticos, ayuda a la reporduccion pero puede afectar la supervivencia) Sexual Dimorphism: Evolution of significant differences between males and females of a species. (Pavos reales). What is gene flow? immigration v. emigration and how they influence diversity in populations. Gene Flow is the transfer of traits (rasgos) in or out of a population, individuals from one population migrate to another and reproduce, they introduce new genetic variants or change the frequencies of existing alleles. Immigration vs Emigration: In immigration the traits move into the population from elsewhere and this often increases trait diversity in the population. In emigration the traits move out of the population to elsewhere and this often decreases trait diversity. What is genetic drift? Random changes in the allele frequencies, due to random events like natural disasters. Define the special cases of genetic drift known as the founder effect and the bottleneck effect and how they can influence variation in populations. Founder Effect: Ocurre cuando un pequeño grupo de individuos se separa de una población más grande y establece una nueva población en un lugar diferente. Bottleneck Effect: Ocurre cuando una población sufre una drástica reducción en su tamaño debido a un evento catastrófico (como un desastre natural, enfermedad o actividad humana).  Know which mechanisms of evolution are random and which are non-random Random mechanisms: Mutation and Genetic drift Non-random mechanisms: Natural selection and nonrandom mating What are the conditions required for natural selection? Why does it not create perfect organisms? Variability: Es decir que en una población existan diferencias geneticas Heritability: Las caracteristicas se puedan transmitir a su descendencia Differential Reproductive Success: Los individuos con diferentes características producen diferentes cantidades de crías que sobreviven y se reproducen. Perfect organisms are not produced due to limited genetic variation, environmental conditions, continuous mutations, among others. What is sexual selection? Describe an example. Competition for Mates/ Attraction of Mates, for example the peacock's tail Describe some of the evidence for evolution in the fossil record. Evolutionary transitions, changes in anatomical structures, chronological orders, convergent and divergent evolution. What is a vestigial structure? How do anatomy and embryology contribute to our understanding of evolution? (also see chp 12) Vestigial Structures that have no apparent function and appear to be residual parts from a past ancestor. The anatomy and embryology provide evidence of shared ancestry between different species. How are DNA sequences useful in determining evolutionary relationships among organisms? Because the more similar the DNA sequences between two species are, the more closely related they are, as these similarities indicate a shared ancestry and the accumulation of mutations over time since their last common ancestor; essentially, the greater the difference in DNA sequences, the more distant the evolutionary relationship between the organisms. How do we define species? What is reproductive isolation? Species: Group of organisms that can interbreed and produce fertile offspring with each other. Reproductive Isolation: The mechanisms that prevent different species from successfully mating and producing viable offspring, essentially acting as a barrier between distinct species, allowing them to evolve separately. (El aislamiento reproductivo es fundamental para la especiación, ya que permite que las poblaciones acumulen diferencias genéticas sin que se mezclen los genes. Con el tiempo, esto puede llevar a la formación de nuevas especies que no pueden cruzarse entre sí.)  Compare the mechanisms of allopatric and sympatric speciation, with an example of each. Allopatric Speciation: Geographic barrier impedes interbreeding between populations due to geologic or environmental process or the population moves to a new geographic location. EX: The Grand Canyon squirrels in Arizona, Natural barriers (the canyon and the river) interrupted gene flow, leading to divergences that eventually produced two distinct species. Sympatric Speciation: Evolutionary process that produces new species without establishing a geographical barrier between populations. This occurs when individuals of the same species stop mating for reasons other than physical separation. EX: Cichlids in the lakes of Africa, Esto ocurrió debido a preferencias en el hábitat, alimentación y selección sexual basada en colores y comportamientos, lo que limitó el apareamiento entre diferentes grupos y dio lugar a múltiples especies. What is adaptive radiation? Es un proceso evolutivo en el que una única especie ancestral se diversifica rápidamente en muchas especies nuevas, cada una adaptada para ocupar un nicho ecológico diferente. Explain the common misconceptions about evolution as detailed in your book. 1. Evolution is just a theory: It is not just a theory, as there is scientific evidence. 2. Humans are descended from modern apes: Humans and chimpanzees share a common ancestor that lived millions of years ago. Modern primates, such as chimpanzees and gorillas, are separate branches of the evolutionary tree, not our direct ancestors. 3. Evolution has a goal: Evolution has no direction or purpose. It is a process driven by natural selection, mutations, genetic drift, and other factors. 4. Organisms evolve because they "need" to adapt: ​Evolution does not occur because an organism "decides" to adapt. Mutations occur randomly, and organisms with advantageous traits are more likely to survive and leave offspring. It is a passive, unintentional process. Chapter 12 What is a phylogeny and a phylogenetic tree? extinct v. extant species Phylogeny: Is the evolutionary history of relationships among organisms. Phylogenetic tree: Is a diagrammatic reconstruction of the evolutionary history of species, populations, and genes. Extinct species: A species is considered extinct when there are no longer any living individuals left anywhere in the world. Extant species: A species is considered extant when it still has living individuals and continues to exist in its natural habitat or in captivity.  Understand how to interpret phylogenetic trees. What do branch points represent? What are sister taxa? know tips, branches, nodes, clades, MRCA, root. Key Components of Phylogenetic Trees: 1. Branch Points (Nodes): ○ Represent a common ancestor shared by the lineages diverging from that point. ○ Each branch point marks a speciation event, where one lineage split into two. 2. Tips (Leaves): ○ The tips of the tree represent extant (living) or extinct species or groups (taxa). ○ Each tip corresponds to a species, genus, or another taxonomic group. 3. Branches: ○ Represent the evolutionary history or lineage leading from one ancestor to its descendants. ○ The length of a branch can sometimes indicate time or genetic change, depending on the tree type. 4. Clades: ○ A clade is a group of organisms that includes a common ancestor and all its descendants. ○ Clades are also called monophyletic groups. 5. Sister Taxa: ○ Two groups or species that are each other’s closest relatives. ○ They share an immediate common ancestor at a single branch point. 6. Most Recent Common Ancestor (MRCA): ○ The MRCA of a set of taxa is the most recent point in evolutionary history from which all taxa in that set are descended. ○ Found at the node connecting those taxa. 7. Root: ○ The root of a phylogenetic tree represents the oldest common ancestor of all taxa in the tree. ○ It indicates the direction of time, from ancestral to derived traits. How to Read a Phylogenetic Tree: 1. Follow the branches: Start from the root and trace the branches to see how species or taxa are related. 2. Understand the nodes: A node indicates a divergence from a common ancestor. 3. Identify clades: Look for groups that include an ancestor and all its descendants. 4. Compare sister taxa: These are the most closely related groups, sharing an immediate common ancestor. 5. Check branch lengths: If provided, longer branches may represent more time or  genetic change. Example: If a tree includes humans, chimpanzees, and gorillas: Node A: Represents the MRCA of humans, chimpanzees, and gorillas. Node B: Represents the MRCA of humans and chimpanzees (making them sister taxa). Clade: Humans and chimpanzees form one clade, while gorillas form a separate sister clade. How do we know if a trait that appears similar in 2 organisms is homologous or analogous? Why is this important? (eg think about comparisons between wings of bats, birds, butterflies…which are homologous, which are analogous) what are vestigial structures. Homologous traits: Traits that are derived from a common ancestor, although they may have different functions in modern organisms. EX: Ala de un murciélago y ala de un pájaro Analogous traits: Traits that have similar functions but do not share a common evolutionary origin. They result from convergent evolution, where different species develop similar solutions to similar environmental problems. EX: Alas de Murciélago vs. Mariposa Understanding homology allows us to build phylogenetic trees and determine evolutionary relationships. Recognizing analogies helps us study how different organisms faced similar challenges through independent solutions. What is morphology? Part of biology that deals with the form of organic beings and the modifications or transformations they undergo.  What is a monophyletic group? polyphyletic? paraphyletic? Monophyletic group: A monophyletic group includes a common ancestor and all of its descendants, also known as a "clade." Example: Mammals form a monophyletic group because they include the common ancestor of all mammals (e.g., humans, whales, dogs) and all of that ancestor's descendants. Polyphyletic group: A polyphyletic group does not include the most recent common ancestor of its members, and organisms grouped together may have separate ancestors. Ex: Grouping flying mammals (bats) with birds and butterflies in a "flying group" would be polyphyletic, since these species do not share a close common ancestor that explains flight. Paraphyletic group: A paraphyletic group includes a common ancestor but does not include all of its descendants. Ex: Reptiles are a paraphyletic group because they include the common ancestor of lizards, snakes, and crocodiles, but exclude birds, which also descend from that ancestor. How is the principle of maximum parsimony used in building phylogenetic trees? What are the different ways that we can reconstruct phylogenies (morphology, behavior, molecular data, paleontology, etc.) and how is each used? Maximum parsimony: Es un principio de la filogenética que se utiliza para construir árboles filogenéticos que representen de manera más precisa la historia evolutiva. Morphology: Anatomical features. Behavior: Behavior can be inherited or culturally transmitted. Bird songs are often learned and may not be a useful trait for phylogenies. Frog calls are genetically determined and can be used in phylogenetic trees. Molecular data: DNA sequences have become the most widely used data for constructing phylogenetic trees. Nuclear, mitochondrial, and chloroplast DNA is used. Gene product information, such as amino acid sequences, is also used. Paleontology: Fossils provide information about morphology of past organisms and where and when they lived. Fossils help determine derived and ancestral traits and when lineages diverged. Limitations: Fossil record is fragmentary and missing for some groups. Development: Similarities in developmental patterns may reveal evolutionary relationships. Example: Sea squirts and vertebrates all have a notochord at some time in their development. Review the system of hierarchical classification introduced by Linnaeus (DKPCOFGS). Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species.Introduced by Carl Linnaeus, this hierarchy organizes biodiversity from broad to specific groups. What is binomial nomenclature, and why is it important? It is the system that uses two Latin names: genus (uppercase) and species (lowercase), e.g., Homo sapiens. Importance: It provides a universal standard for naming species, avoiding confusion between languages ​or regions. Chapter 13 What are the 2 major groups of prokaryotes and how are they different? Bacteria: They have peptidoglycan in their cell wall. Archaea: They lack peptidoglycan and live in extreme environments. Differences: Membrane composition, metabolism, and environments where they live. El peptidoglicano es un polímero que forma la pared celular de la mayoría de las bacterias. How old is planet earth? How do we know? Approximately 4.54 billion years. Determined by radiometric dating of terrestrial minerals and meteorites How long ago did the first living cells arise and what type of cells were they? They emerged 3.5-3.8 billion years ago,They were probably prokaryotes, like anaerobic bacteria. Define cyanobacteria and stromatolites. How did they change conditions on early earth? What are extremophiles? Cyanobacteria: Photosynthetic organisms that released oxygen, causing the Great Oxidation Event. Stromatolites: Fossilized structures created by cyanobacteria. Extremophiles: Organisms that thrive in extreme conditions, such as high temperatures or high salinity. How do bacteria reproduce? What are the two methods of asexual reproduction? Asexual: Binary division. Other Methods: Conjugation: Exchange of DNA between bacteria. Transformation and Transduction: Absorption or transfer of genetic material. Know the terms pathogenic, pandemic, epidemic. What is bioremediation? Pathogenic: Disease-causing organism. Pandemic: Global epidemic. Epidemic: Disease that affects many people in a region. Bioremediation: Use of microorganisms to clean contaminated environments. What is commensalism? What is a parasite? What is phagocytosis? Commensalism: One species benefits without harming the other. Ex: a bird's nest on a tree. Parasite: It lives at the expense of its host. For example, fleas and ticks. Phagocytosis: Process in which a cell engulfs large particles or microorganisms. Why do we have so many microbes that are resistant to antibiotics? Due to excessive and incorrect use of antibiotics, bacteria develop resistant mutations. Describe endosymbiotic theory and the evidence to support it. Explains how mitochondria and chloroplasts arose from symbiotic bacteria. Evidence: Self-DNA, prokaryote-like ribosomes, and double membrane. Los microorganismos simbióticos son aquellos que necesitan asociarse con otros organismos para desarrollarse. Approximately how long ago did the first eukaryotes appear on earth? They appeared approximately 1.8 billion years ago.  What do most “protists” have in common? Describe some examples that are harmful (human/plant pathogens) and beneficial. A diverse group of eukaryotes. Examples: Pathogens: Plasmodium (malaria). Beneficial: Algae that produce oxygen. How are fungi different from animals and plants? To which group are they more closely related? What is a saprobe? How do fungi obtain nutrition? What is mycorrhizae? Fungi are distinct from both plants and animals because they are heterotrophic like animals, but unlike animals, they cannot move to find food. They are closer to animals than to plants. Saprobe: They decompose organic matter. They obtain nutrition by absorption of nutrients from the environment around them. Mycorrhizae: Symbiotic associations with plant roots. What are some benefits provided by fungi? What is a lichen? The benefits are antibiotics, food, and nutrient recycling. Lichen: Symbiosis between fungi and algae/cyanobacteria. Chapter 14 Why are plants important? They generate oxygen, produce food, regulate climate, and provide habitats. What adaptations were required for an aquatic plant to adapt to life on land? Cuticle, stomata, vascular tissues, and seeds. Describe the alternation of generations found in plants. "Alternation of generations" in plants refers to the life cycle where a plant switches between two distinct phases: a haploid "gametophyte" stage that produces gametes (sex cells) and a diploid "sporophyte" stage that produces spores. Compare vascular and nonvascular plants. What are apical meristems? Vascular:They have xylem and phloem. Nonvascular: They lack xylem and phloem. Apical meristems: Growth zones in roots and shoots. What are xylem and phloem—why are they important? Xylem: Carries water Phloem: Carries nutrients What is the cuticle and why is it important? What about stomata? Cuticle: A cuticle is a waxy, waterproof layer that covers the outer surface of plants, primarily leaves and stems, acting as a protective barrier against water loss by preventing excessive evaporation. Stomata: Stomata are tiny pores on the leaf surface that open and close to regulate gas exchange, allowing carbon dioxide in for photosynthesis and releasing oxygen, while also controlling water loss through transpiration. Compare seedless and seed plants Seeds: Better protection and dispersal. Seedless: Propagation by spores. Compare gymnosperms and angiosperms. Gymnosperms: Naked seeds (pines). Angiosperms: Seeds in fruits (flowers).  Know the examples of plants for each group covered. Mosses (non-vascular), ferns (seedless), pines (gymnosperms), roses (angiosperms). What is the importance of flowers and fruits? Flowers: Pollination. Fruits: Seed dispersal. Know the parts of a flower—what are their purpose and be able to label them Sepal: Sepals are the exterior parts of a flower that protect the interior flower while it emerges. Petals: Petals exist to draw pollinators to the flower. Statement: The stamen is the male reproductive organ of a flower. Carpel: Also sometimes called the pistil, is the female reproductive organ of a flower. Know the difference between monoecious and dioecious. Monoecious: Both sexes in one plant. Dioecious: Separate plants for each sex. What is the difference between monocots and dicots? understand and be able to identify. Monocots: One embryonic leaf. Dicots: Two embryonic leaves. Los monocotiledóneas tienen pétalos en múltiplos de tres (3,6,9). Las dicotiledóneas tienen pétalos en múltiplos de cuatro o cinco (4,8,12 o 5,10). Be able to describe important adaptions for plants living in different environments (eg desert v., forest floor, v. rainforest) Deserts: Water storage. Tropical rainforest: Large leaves to capture light.