BISC 1112- Study Guide - Exam 1
BISC 1112- Study Guide - Exam 1 BISC1112
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This 7 page Study Guide was uploaded by Nikita Shah on Monday February 8, 2016. The Study Guide belongs to BISC1112 at George Washington University taught by Doebel in Spring 2016. Since its upload, it has received 70 views. For similar materials see ntroBio-Bio of Organisms (BISC 1112) in Biology at George Washington University.
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Date Created: 02/08/16
Nikita Shah BISC 1112 Study Guide Chapter 25.1-25.4 Macroevolution: the broad pattern of evolution above the species level. o Ex. The emergence of terrestrial vertebrates through a species of speciation events, the impact of mass extinctions on biodiversity, and the origin of key adaptation such as light Early life (cells) were created through four main stages: 1. The abiotic (non-living) synthesis of small organic molecules, such as amino acids and nitrogenous bases 2. The joining of these small molecules into macromolecules, such as proteins and nucleic acids 3. The packaging of these molecules into protocells, droplets with membranes that maintained an internal chemistry different from that of their surrounding 4. The origin of self-replicating molecules that eventually made inheritance possible Hypotheses of how the early life formed: 1920s: Russian Chemist A.I. Oparin and British scientist J.B.S. Haldane thought the Earth’s early atmosphere was a reducing (electron-adding) environment, in which organic compounds could have formed from simpler molecules 1953: Stanley Miller and Harold Urey tested this out and successfully created amino acids and organic compounds Later evidence showed that the atmosphere could have been ‘neutral’ (neither oxidizing nor reducing) 2008 study: found that numerous amino acids had formed under conditions that simulated a volcanic eruption Another hypothesis suggested that organic compounds were first produced in deep-sea hydrothermal vents, areas on the seafloor where heated water and minerals gushed from Earth’s interior into the ocean. Alkaline Vents, another deep-sea vent, release water that has a high pH (9-11) and is warm rather than hot, and is thought to be more suitable for the origin of life Meteorites hitting the earth are also thought of create key organic molecules Amino Acids and RNA nucleotides polymerize when dripped onto hot sand, clay, or rock The first genetic material may have been self-replicating, catalytic RNA o Such RNA catalyst are called ribozymes and can make complementary copies of short pieces of RNA, provided that they are supplied with nucleotide building blocks Early protocells containing such RNA would have increased through natural selection Strata: sedimentary rock layers in which fossils have accumulated Radiometric Dating: the most common technique to discover the age of a fossil; based on the decay of radioactive isotopes Half-Life: rate at decay; the time required for 50% of the parent isotope to decay Tetrapod: group of animals having four limbs (mammals) Geologic Record: a standard time scale that divides Earth’s history into four eons and further subdivisions The first 3 eons (lasted approx. 4 billion years): The Hadean origin of solar system and earth The Achaean oldest fossils of prokaryotes appear; oxygen increase in atmosphere (oxygen revolution) The Proterozoic (half a billion years, encompasses most of the time animals have existed) includes: o The Paleozoic inc. in diversity; insects and tetrapods appear o The Mesozoic age of reptiles o The Cenozoic most recent era (where humans first appear) Stromatolites: layers rocks that form when certain prokaryotes bind thin films of sediment together; first single celled organisms Endosymbiont Theory: which posits that mitochondria and plastids were small prokaryotes that began living within larger cells (called a host cell) and soon evolved into one single cell Theory of serial endosymbiosis suggests that mitochondria evolved before plastids through a sequence of endosymbiotic events Cambrian Explosion: when many present-day animal phyla appear suddenly in fossils formed 535-525 million years ago Prior to this explosion, animal groups were soft bodied and there was little evidence of predation Plate Tectonics: the continents are part of great plates of Earth’s crust that essentially float on the hot, underlying portion of the mantle Movements in the mantle cause the plates to move over time in a process called continental drift About 250 million years ago, plate movements brought previously separated landmasses together into a supercontinent named Pangaea This explains why some fossils of the same species are found in two different continents Mass Extinction: large numbers of a species become extinct worldwide There are ‘big five’ mass extinctions in the pass 500 million years where 50% or more of marine species become extinct o The Permian (volcanic eruption) and the Cretaceous (meteorite) have received the most attention Adaptive Radiations: periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to f ill different ecological roles, or niches, in their communities Chapter 32.1-32.3 Tissues: groups of similar cells that act as a functional unit. Ex. Muscle tissue and nervous tissue are responsible for moving the body and conducting nerve impulses, respectively. Cleavage: a succession of mitotic cell division without cell growth between the divisions after a diploid zygote is formed Blastula: Cleavage produces a multicellular stage called a blastula, typically a hollow ball of cells that surround a cavity called the blastocoel Gastrulation: The layers of embryonic tissues that will develop into adult body parts are produced; a process in which one end of the embryo folds inward, expands, and eventually fills the blastocoel, producing layers of embryonic tissues: the ectoderm (outer layer) and the endoderm (inner layer) Ectoderm: the germ layer covering the surface of the embryo, gives rise to the outer covering of the animal and, in some phyla, to the central nervous system Endoderm: the innermost germ layer, lines the pouch that forms during gastrulation (the archenteron) and gives rise to the lining of the digestive tract (or cavity) and organs such as the liver and lungs of vertebrates Diploblastic: Cnidarians and a few other animal groups that have only 2 germ layers (ectoderm and endoderm) Mesoderm: All bilaterally symmetrical animals contain this third middle layer which fills most of the space between the ectoderm and the endoderm; forms the muscles and most other organs between the digestive tract and the outer covering of the animal o Triploblastic: having three germ layers Gastrula: Resulting developmental stage from gastrulation Larva: a sexually immature form of an animal that is morphologically distinct from the adult, usually eats different food, and may even have a different habitat than the adult. Ex. Mosquitos Metamorphosis: animal larvae eventually undergo this developmental transformation that turns the animal into a juvenile that resembles an adult but is not yet sexually mature Hox Genes: play important roles in the development of animal embryos, controlling the expression of many other genes that influence morphology Ediacaran Biota: early group of soft-bodied multicellular eukaryotes, where the first generally accepted macroscopic fossils of animals date (560 million years ago) Bilaterians: most of the fossils from the Cambrian explosions who have a two-sided or bilaterally symmetric form and a complete digestive tract, an efficient digestive system that has a mouth at one end and an anus at the other Body plan: a particular set of morphological and developmental trails, integrated into a functional whole – the living animal; provide a succinct way to compare and contrast key animal features Radial Symmetry: type of symmetry found in a flowerpot; does not have a left/right side; any imaginary slice through the central axis divides the animal into mirror images Bilateral Symmetry: two sided symmetry, has two axes of orientation: front to back and top to bottom. Most bilateral animals have a central nervous system; Ex. shovel Dorsal: top Ventral: bottom Anterior: front end Posterior: back end Body Cavity: a fluid or air-filled spaced located between the digestive tract and the outer body wall; its fluid cushions the suspended organs, helping to prevent internal injury; enables the internal organs to grow and move independently of the outer body wall Also called the coelom which forms tissue derived from the mesoderm Coelomates: animals with a true coelom; in animals such as earthworms: the coelom contains non-compressible fluid that acts like a skeleton against which muscles can work Pseudocoelomates: animals that are triploblastic that have a body cavity formed from the mesoderm and the endoderm Acoelomates: some triploblastic animals that lack a body cavity all together Protostome Development: eight-stage cell: spiral and determinant; solid masses of mesoderm split and form coelom; mouth develops from blastopore Deuterostome Development: eight-stage cell: radial and indeterminate; coelom forms by folds of archenteron; anus develops from blastopore Spiral Cleavage: the planes of cell division are diagonal to the vertical axis of the embryo; smaller cells are center over the grooves between larger, underlying cells Determinate Cleavage: this determines the developmental fate of each embryonic cell very early Radial Cleavage: cleavage planes are either parallel or perpendicular to the vertical axis of the embryo; the tiers of the cell are aligned, one directly above the other Indeterminante Cleavage: what most animals with deuterostome development have, meaning that each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo (this can make human twins occur) Archenteron: embryo’s developing digestive tube that initially forms as a blind pouch, which becomes the gut; after this develops, in most animals a second opening forms at the opposite end of the gastrula (mouth/anus) Blastopore: the indentation that during gastrulation leads to the formation of the archenteron Chapter 27.1-2 The term polytomy refers to a situation in which Prokaryotes: unicellular, contains a cell wall, much smaller than many eukaryotic cells, well organized, and achieves all of an organism’s life functions within a cell Contains a cell wall made up of peptidoglycan, a polymer composed of modified sugars cross-linked by short polypeptide’s, that help the cell not burst in a hypertonic environment o Archaeal cell walls contain other proteins but lack peptidoglycan Gram stain: a technique where scientist can figure out the composition of a cell wall to figure out the bacterial species Gram positive: bacterial have simpler walls with a relatively large amount of peptidoglycan Gram negative: bacteria have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides Capsule: cell wall of many prokaryotes that is surrounded by a sticky layer of polysaccharide or protein that is dense and well defined to protect against dehydration and pathogens If it is not as well organized it is called a slime layer Endospores: certain bacteria develop this type of resistant cell when they lack an essential nutrient Fimbriae: hair-like appendages in which prokaryotes stick to their substrate or to one another through Pili: appendages that pull two cells together prior to DNA transfer from one cell to the other Taxis: directed movement toward or away from a stimulus (half of all prokaryotes are capable of this) Ex. Moving towards a chemical or light Most common method of movement is a flagella Exaptation: the process in which existing structures take on new functions through descent with modification Nucleoid: found in prokaryotes in which a region of cytoplasm that is not enclosed by a membrane, in replace of a nucleus Binary Fission: how prokaryotic cells divide: 1 single cell divides into 2 and then 248, etc. Genetic Recombination: the combining of DNA from two sources Eukaryotes: meiosis and fertilization Prokaryotes: transformation, conjugation, and transduction Horizontal Gene Transfer: the movement of genes from one organism to another when the individuals are members of different species Transformation: the genotype and possibly the phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings Transduction: phages carry prokaryotic genes from one host cell to another Conjugation: DNA is transferred between two prokaryotic cells (usually of the same species) that are temporarily joined F Factor: the ability to form pili and donate DNA during conjugation results from the presence of a particular piece of DNA called the F factor F Plasmid: created from the F factor in its plasmid form where designated F+ cells function as DNA donors during conjugation Hfr Cell: (high frequency for recombination) a cell with the F factor built into its chromosome When chromosomal DNA from a Hfr cell enters a F- cell, homologous regions of the HFr and F- cell chromosomes may align, and allows segments of their DNA to be exchanged, causing recombination R Plasmids: plasmids that carry resistant genes Chapter 28.1-3 Eukaryotes have a cytoskeleton that extends throughout the cell which prokaryotes lack o This helps the cell change in shape as they feed, move, and grow Mixotrophs: combine photosynthesis and heterotrophic nutrition Endosymbiosis: a relationship between two species in which one organism lives inside the cell or cells of another organism (host) How mitochondria evolved before plastids Algae: photosynthetic protists including red algae and green algae Secondary Endosymbiosis: what the algae went through where they were ingested in the food vacuoles of heterotopic eukaryotes and became endosymbionts themselves Excavata: a clade that was originally proposed based on morphological studies of the cytoskeleton Diplomonads: contain reduced mitochondria called mitosomes that lack functional electron transport chains and hence cannot use oxygen to help extract energy from carbohydrates and other organic molecules. Instead they get energy from anaerobic biochemical pathways Parabasalids: contained reduced mitochondria, called hydrogenosomes, that generate some energy anaerobically, releasing hydrogen as a by-product Euglenozoans: contains a rod with either a spiral or crystalline structure inside its flagella Kinetoplastids: contain a single, large mitochondrion that contains an organized mass of DNA called a kinetoplast Euglenid: contains a pocket at one end of the cell from which one or two flagella emerge; some are mixotrophs
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