Exam #3 - Aaliyah Franco PDF

Chapter 14 (Evolution) Charles Darwin (1809–1882) was an English naturalist and biologist best known for developing the theory of evolution through natural selection. He proposed that species evolve over time due to variations that allow some individuals to survive and reproduce more successfully i...

Chapter 14 (Evolution) Charles Darwin (1809–1882) was an English naturalist and biologist best known for developing the theory of evolution through natural selection. He proposed that species evolve over time due to variations that allow some individuals to survive and reproduce more successfully in their environments. This work laid the foundation for modern evolutionary biology and significantly influenced scientific thinking. Darwin’s hypothesis for evolutionary change, after much testing, eventually became accepted as theory Describe the fossils and patterns for the variation in beak lengths among the Galapagos finches Fossils of extinct organisms resembled those of living organisms Geographical patterns suggested that organismal lineages change gradually as individuals move into new habitats Islands have diverse animals and plants that are related to, yet different from, their mainland sources Finches with large, strong beaks could crack tough seeds, while those with long, narrow beaks fed on insects. These variations emerged as finches adapted to different food sources, showcasing natural selection in action. Fossils of extinct organisms resemble living species, suggesting evolutionary change over time. In the Galapagos, finch beak sizes evolved to suit their specific food sources. For example, finches feeding on seeds had large beaks, while those eating insects had smaller beaks. This phenomenon, called "descent with modification," highlights how species adapt to their environment via natural selection​ Darwin observed that beak shape varies among finch species. He postulated that the beak of an ancestral species had adapted over time to equip the finches to acquire different food sources Describe the impact of ecological niches Ecological niches describe how species interact with their environment, including how they use resources to survive. Darwin’s finches are a prime example of species evolving to occupy different niches. Each finch species evolved beaks suited to the food available in their habitat, which allowed them to survive and reproduce successfully​ Differentiate between homologous and analogous structures Homologous structures are derived from a common ancestor but may serve different functions in different species, like the bones in the wings of bats and the arms of humans Analogous structures serve similar functions but evolved independently, such as the wings of birds and insects. State the Hardy-Weinberg rule and its assumptions The Hardy-Weinberg rule states that allele frequencies in a population will remain constant from generation to generation if certain conditions are met. These include: 1. A very large population 2. Random mating 3. No mutations 4. No immigration or emigration 5. No natural selection​ Discuss the five factors that influence Hardy-Weinberg proportions Five key factors can disrupt Hardy-Weinberg equilibrium: 1. Mutation: introduces new alleles to the gene pool. 2. Nonrandom mating: alters genotype frequencies. 3. Genetic drift: random changes in allele frequencies due to chance. 4. Migration: introduces or removes alleles as individuals move between populations. 5. Selection: favors certain alleles that provide a survival advantage​ Compare stabilizing, disruptive, and directional selection Stabilizing selection eliminates extreme phenotypes, favoring the average. An example is human birth weight, where extremely low or high weights are less common. Disruptive selection favors extreme phenotypes at both ends, eliminating intermediates. An example is the beak size in African finches, where only small or large beaks are advantageous. Directional selection favors one extreme phenotype, shifting the population's traits. For example, selecting for flies that avoid light​ Explain how stabilizing selection maintains sickle-cell disease Sickle-cell anemia is maintained in populations because of heterozygote advantage. Individuals with one sickle-cell allele are resistant to malaria, which is prevalent in certain regions. Stabilizing selection occurs because this advantage outweighs the lethal effects of having two sickle-cell alleles​ Describe five prezygotic isolating mechanisms and two postzygotic isolating mechanisms Prezygotic isolating mechanisms prevent mating or fertilization between species: 1. Geographical isolation 2. Ecological isolation 3. Temporal isolation (different mating seasons) 4. Behavioral isolation (differences in courtship) 5. Mechanical isolation (physical differences) 6. Prevention of gamete fusion (incompatibility of sperm and egg) Postzygotic isolating mechanisms prevent the hybrid offspring from developing properly or reproducing: 1. Hybrid inviability (offspring do not develop or survive) 2. Hybrid sterility (offspring are sterile, e.g., mules)​ Chapter 15 ( Kingdoms of life - Nomenclature) Compare the classification systems of Aristotle, the Middle Ages, and Linnaeus Aristotle: Classified organisms based on observable traits, dividing them into plants and animals, and animals into those with or without blood. While simple, it did not account for evolutionary relationships. Middle Ages: Involved polynomial names—long Latin descriptions for organisms based on subjective traits. This system lacked standardization and was inefficient. Linnaeus: Introduced the binomial system, giving each organism a two-part name (genus + species) and grouping organisms into hierarchical categories based on traits. This system is standardized and universally recognized, though it initially focused only on physical traits, without considering evolutionary relationships​ Differentiate between polynomial and binomial systems Polynomial system: Used descriptive, non-standardized Latin names, often long and inefficient. Binomial system: Developed by Linnaeus, this system assigns organisms a two-part Latin name: Genus (capitalized) and species (lowercase), written in italics or underlined. It is more concise and standardized​ Define taxon, domain, derived character, clade, outgroup, and phylogeny Taxon: A group of organisms classified at any hierarchical level (e.g., species, genus). Domain: The highest taxonomic rank, which groups life into three categories: Bacteria, Archaea, and Eukarya. Derived character: A trait that appears in recent lineages but not in older ancestors, used to determine evolutionary relationships. Clade: A group of organisms sharing a common ancestor, identified by shared derived characters. Outgroup: A species or group used for comparison in cladistic analysis, usually more distantly related to the group being studied. Phylogeny: The evolutionary history and relationships among species or groups of organisms, often depicted in a phylogenetic tree​ Describe the two parts of a scientific name 1. Genus: The first part of the name, always capitalized (e.g., Homo). 2. Specific epithet: The second part, referring to the species, is written in lowercase (e.g., sapiens). Together, they form the species name, e.g., Homo sapiens​ List the eight categories used to classify organisms, in order of increasing inclusiveness 1. Species 2. Genus 3. Family 4. Order 5. Class 6. Phylum 7. Kingdom 8. Domain​ Name and describe the six kingdoms of life, and assign to one of three domains of life Kingdoms: 1. Bacteria: Prokaryotic organisms with peptidoglycan cell walls. 2. Archaea: Prokaryotic, often extremophiles, with unique cell membranes and RNA sequences. 3. Protista: Diverse eukaryotic organisms, mostly unicellular. 4. Plantae: Multicellular, photosynthetic organisms with cell walls made of cellulose. 5. Fungi: Eukaryotic organisms that absorb nutrients, with chitin in their cell walls. 6. Animalia: Multicellular, eukaryotic organisms that ingest food. Domains: 1. Bacteria: Includes the kingdom Bacteria. 2. Archaea: Includes the kingdom Archaea. 3. Eukarya: Includes the kingdoms Protista, Plantae, Fungi, and Animalia​ Discuss the uniqueness of bacteria, archaea, and eukarya Bacteria: Most abundant organisms have peptidoglycan in their cell walls, and reproduce through binary fission. They are found in various environments and can be autotrophic or heterotrophic. Archaea: Prokaryotes that thrive in extreme environments (e.g., high temperatures, salinity), have unique membrane lipids, and lack peptidoglycan in their cell walls. Some share similarities with eukaryotes. Eukarya: Organisms with complex cell structures, including a defined nucleus and organelles such as mitochondria and chloroplasts. Eukaryotes are divided into Protista, Plantae, Fungi, and Animalia​ Contrast the diversity of Kingdom Protista with the other three eukaryotic kingdoms Protista: The most diverse kingdom, containing mostly unicellular organisms (though some are multicellular) that can be autotrophic, heterotrophic, or both. Protists do not fit into the other eukaryotic kingdoms. Other Eukaryotic Kingdoms: Plantae (multicellular, autotrophic), Fungi (multicellular, absorb nutrients), and Animalia (multicellular, heterotrophic) are more specialized compared to the broad diversity found in Protista Discuss the role of symbiosis in the evolution of eukaryotes Endosymbiosis played a key role in the evolution of eukaryotic cells. It is believed that mitochondria and chloroplasts originated from prokaryotic cells that were engulfed by ancestral eukaryotic cells. These prokaryotes formed a symbiotic relationship with the host cell, eventually evolving into organelles. This theory is supported by the fact that mitochondria and chloroplasts have their own DNA and replication similarly to prokaryotes​. Chapter 16 ( The First Single-Celled Organisms) Define prokaryote, capsule, pilus, endospore,and conjugation. Define bacteriophage,prophage,and gene conversion. Prokaryote: Single-celled organisms lacking a nucleus and membrane-bound organelles (e.g., bacteria and archaea). Capsule: A gelatinous outer layer found in some bacteria, protecting them from desiccation and immune attacks​. Pilus: Hair-like appendages used by bacteria to attach to surfaces or during conjugation, a process where DNA is transferred between bacteria​. Endospore: A tough, dormant structure produced by some bacteria to survive extreme environmental conditions​. Conjugation: The transfer of genetic material between bacterial cells via a pilus, acting like a bridge between a donor and recipient​. Bacteriophage: A virus that infects bacteria. Prophage: The viral DNA incorporated into the bacterial genome during the lysogenic cycle​. Gene Conversion: The expression of viral genes that have integrated into the host genome during lysogeny​ Describe the two kinds of prokaryotic exteriors Gram-positive: Bacteria with thick peptidoglycan cell walls, stain purple in a Gram stain. Gram-negative: Bacteria with thin peptidoglycan layers and an outer membrane, stain pink, and are often more resistant to antibiotics​ Distinguish between autotroph and heterotroph. Contrast photo- and chemoautotrophs Autotrophs: Organisms that synthesize their own food using inorganic carbon (e.g., CO₂). Photoautotrophs: Use sunlight for energy (e.g., plants and cyanobacteria). Chemoautotrophs: Use chemicals like sulfur or iron to produce energy. Heterotrophs: Obtain carbon and energy from organic molecules produced by other organisms​ Describe the three significant contributions of prokaryotes to the world ecosystem Decomposition: Prokaryotes break down dead organic material, recycling nutrients. Nitrogen fixation: Some prokaryotes convert atmospheric nitrogen into a form usable by plants. Bioremediation: Prokaryotes can break down pollutants like oil in contaminated environments​ Contrast the metabolisms of archaea and bacteria Archaea: Often extremophiles, metabolizing in harsh conditions (e.g., methanogenesis in anaerobic environments). Bacteria: Metabolize in more typical environments and have greater metabolic diversity, including nitrogen fixation and photosynthesis Assess whether viruses are alive Viruses are not considered alive because they cannot reproduce independently and must infect a host cell to replicate. They lack cellular structure and metabolism, depending entirely on the host for replication​ Contrast the lytic and lysogenic cycles Lytic cycle: The virus immediately replicates after infecting the host, eventually lysing (breaking) the host cell to release new viral particles​(BIOL 101 Chapter 16.pp…). Lysogenic cycle: The viral DNA integrates into the host genome as a prophage and remains dormant until triggered to enter the lytic cycle​ Describe the four phases of the HIV infection cycle Attachment: HIV binds to the CD4 receptor on T-helper cells. Fusion and entry: The viral envelope fuses with the host cell membrane, releasing viral RNA. Replication: The RNA is reverse-transcribed into DNA, which integrates into the host genome. Assembly and release: New viral particles are assembled and released to infect other cells​ Define and describe emerging viruses Emerging viruses are those that have recently appeared or have the potential to cause outbreaks in new populations. They often arise from mutations or jumps between species. Examples include the Ebola virus and SARS-CoV Chapter 17 ( Protists: Advent of the Eukaryotes) Define eukaryote, protist: Eukaryote: Eukaryotic cells are complex cells with a nucleus and other organelles enclosed within membranes. Eukaryotes include organisms like animals, plants, fungi, and protists. Protist: Protists are a diverse group of eukaryotic organisms that do not fit into the traditional categories of plants, animals, or fungi. They exhibit varied characteristics and include both unicellular and multicellular organisms. Origin of the nucleus and endoplasmic reticulum: The nucleus and endoplasmic reticulum (ER) in eukaryotic cells are believed to have evolved from infoldings of the outer membrane in ancient bacterial cells. These infoldings likely extended inward, eventually forming separate, internal structures like the nuclear envelope and the ER​. Contrast sexual and asexual reproduction: Sexual reproduction involves two parents who contribute gametes (haploid cells) that combine to form a diploid offspring. This process promotes genetic diversity. Asexual reproduction involves a single organism producing offspring genetically identical to itself, often through methods like binary fission or budding. This type does not involve the formation of gametes. When most protists reproduce sexually vs. asexually: Most protists primarily reproduce asexually under favorable conditions for rapid population growth. However, during stressful conditions, such as changes in the environment, they may switch to sexual reproduction as a survival strategy, producing genetically diverse offspring that may better withstand the adverse conditions​. Distinguish multicellular individuals, cell aggregates, and colonial organisms: Multicellular individuals: Organisms with specialized cells that coordinate activities for the organism’s function. Cell aggregates: Loose collections of cells that may come together temporarily but do not form a cohesive structure or specialized functions. Colonial organisms: Groups of connected but similar cells that can live independently or as part of a structured community, often showing minimal specialization​. Contrast locomotion among ciliates, dinoflagellates, and sporozoans: Ciliates use numerous hair-like structures called cilia for movement and feeding. Dinoflagellates possess two flagella, allowing a spinning motion, and many are photosynthetic. Sporozoans (like Apicomplexa) are non-motile, relying on host organisms for movement as they are typically parasitic​. Contrast red and green algae: Red algae (Rhodophyta) are mostly multicellular and lack flagella; they contain pigments like phycoerythrin, giving them a red color. Green algae (Chlorophyta) include unicellular, colonial, and multicellular forms and contain chlorophylls similar to land plants. They are ancestors of land plants and are generally green in color due to chlorophyll a and b​. Chapter 22 Part 1 ( Evolution of the Animal Phyla) Five features that all animals have in common: Animals are heterotrophs (they obtain energy by consuming other organisms). They are multicellular and lack cell walls. Animals are generally capable of movement. They have diverse forms and habitats. Most animals reproduce sexually and follow a common embryonic development pattern​(BIOL 101 Chapter 22 Par…). Six key transitions in the animal body plan: Development of tissues. Bilateral symmetry. Evolution of a body cavity. Deuterostome development. Molting (found in organisms like nematodes and arthropods). Segmentation​. Radial vs. Bilateral symmetry: Radial symmetry: The body can be divided into similar halves along multiple planes passing through the central axis, allowing interaction from all directions. Bilateral symmetry: The body has a distinct right and left side, with only one plane that divides it into mirror images, facilitating specialization of body regions​. Key body innovation of different animal groups: Sponges (Porifera): Lack tissues; have specialized cells for filtration. Cnidarians: Developed tissues and have a gastrovascular cavity for extracellular digestion. Solid worms (Platyhelminthes): Acoelomate (no body cavity) structure with basic organs. Nematodes: Pseudocoelom and a complete digestive system. Mollusks: True coelom and specialized organs. Annelids: Segmented body. Arthropods: Segmentation, exoskeleton, and molting. Echinoderms: Radial symmetry and a water vascular system. Chordates: Notochord, dorsal nerve cord, and post-anal tail​. Acoelomate, pseudocoelomate, and coelomate: Acoelomate: No body cavity; solid body structure. Pseudocoelomate: Body cavity between the mesoderm and endoderm (pseudocoelom). Coelomate: Body cavity (coelom) entirely within the mesoderm​. Four differences between protostomes and deuterostomes: Cleavage pattern: Protostomes exhibit spiral cleavage; deuterostomes exhibit radial cleavage. Blastopore fate: In protostomes, the mouth forms from the blastopore, while in deuterostomes, the anus develops from it. Coelom formation: Protostomes form a coelom through splitting of the mesoderm; deuterostomes form it through outpocketing of the gut. Developmental flexibility: Protostomes typically have determinate development; deuterostomes have indeterminate development​. Chapter 22 Part 2 ( Evolution of the Animal Phyla) Five Features Common to All Animals: Five common features across animals include multicellularity, heterotrophy, motility at some life stage, lack of cell walls, and specialized sensory organs. Six Key Transitions in the Animal Body Plan: Specifics generally include the evolution of tissues, symmetry, body cavities, segmentation, cephalization, and development patterns (protostome vs. deuterostome). Radial vs. Bilateral Symmetry: Radial symmetry is where body parts are arranged around a central axis, typical in organisms like cnidarians. Bilateral symmetry has a single plane dividing the body into two mirrored halves, common in more complex animals, allowing for directional movement and cephalization. Key Body Innovation of Each Group: Sponges: No true tissues; rely on specialized cells. Cnidarians: Radial symmetry and simple tissues. Solid worms (flatworms): Development of a central nervous system. Nematodes: Complete digestive tract (mouth-to-anus). Mollusks: Coelomate body with distinct head, foot, and mantle. Annelids: Segmented bodies. Arthropods: Jointed appendages and exoskeleton. Echinoderms: Water vascular system. Chordates: Notochord and endoskeleton. Acoelomate, Pseudocoelomate, and Coelomate: Acoelomate: Lacks a body cavity (e.g., flatworms). Pseudocoelomate: Has a body cavity partially lined with mesoderm (e.g., roundworms). Coelomate: Has a fully lined body cavity with mesoderm (e.g., annelids, mollusks). Four Differences between Protostomes and Deuterostomes: Protostomes: Spiral cleavage, mouth forms first, schizocoelous development, and determinant cleavage. Deuterostomes: Radial cleavage, anus forms first, enterocoelous development, and indeterminate cleavage.