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147 Cards in this Set
- Front
- Back
Seven characteristics shared between living systems
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1. Cellular Organization 2. Ordered Complexity 3. Sensitivity 4. Growth, development, and reproduction 5. Uses energy 6. Homeostasis 7. Evolutionary adaptation
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Levels of Organization: Cellular Level
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1. Atoms 2. Molecules 3. Organelles 4. Cells
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Levels of Organization: Organism Level
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1. Tissues 2. Organs 3. Organ Systems 4. Organism
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Levels of Organization: Population Level
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1. Population 2. Species 3. Community 4. Ecosystem
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Emergent Properties
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At each higher level in the living hierarchy, new properties emerge. These emergent properties result from the way in which components interact, and they often cannot trace it just from looking at the parts themselves.
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Deductive Reasoning
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Applies general principles to predict specific results
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Inductive Reasoning
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The logic flows in the opposite direction, from the specific to the general. It uses specific observations to develop a general conclusion.
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Hypothesis
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A possible explanation for an observation
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Experiment
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The test of a hypothesis
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Variables
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Many factors
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Test Experiment
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One variable is altered in a known way to test a particular hypothesis
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Control Experiment
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The particular variable is left unaltered
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Reductionism
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An approach scientists use to understand a complex system by reducing it to its working parts
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Models
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To imitate phenomena that are difficult to study directly
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Theory (2 Definitions)
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1. A proposed explanation for some natural phenomenon and is often based on a general principle 2. The body of interconnected concepts, supported by scientific reasoning and experimental evidence, that explains the facts in some area of study.
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Artificial Selection
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Animal breeders select certain varieties to produce certain characteristics. It produces a lot of different traits ex. dogs, cows
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Natural Selection
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Nature selects certain varieties to produce certain characteristics
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Homologous Structures
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Structures that are shared by related species and that have been inherited from a common ancestor. ex. the differently shaped front limbs of modern vertebrates
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Analogous Structures
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Structures that have similar function but different evolutionary origins ex. The wing of a bee and the wing of a bird are analogous structures.
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Phylogenetic Tree
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The pattern of descent obtained and it represents the evolutionary history of the gene. It's "family tree". Shows evolutionary relationships
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Cell Theory
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Proposed by Schleiden and Schwann 1. All living organisms consist of cells 2. All cells come from preexisting cells 3. Cells are the smallest living things, the basic unit of organization of all organisms
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Molecular Basis of Inheritance
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DNA encodes genes which control living organisms and are passed from one generation to the next
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Cells Information Processing System
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Cells process information stored in DNA as well as information received from the environment
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Structure and function
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1. The proper function of a molecule is dependent on its structure 2. The structure of a molecule can tell us about its function
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Evolutionary Change
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Living organisms have evolved fro the same origin event. The diversity of life is the result of the evolutionary change.
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Evolutionary Conservation
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Critical characteristics of early organisms are preserved and passed on to future generations
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Evolution
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Modification of a species over generations, "descent with modification"
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Natural Selection
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Individuals with superior physical or behavioral characteristics are more likely to survive and reproduce than those without such characteristics
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Surface area-to-volume ratio
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As a cell's size increases, it's volume increases much more faster than it's surface area
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Resolution
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The minimum distance two points can be apart and still be distinguished as two separate points
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Prokaryote
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The simplest organisms, and most of their genetic materiel lies in a singular cellular molecule of DNA
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Nucleoid
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The center of the cell
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Cytoplasm
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Fills the interior of the cell and contains all of the sugars, amino acids, and proteins the cell uses to carry out its everyday activities
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Organelles
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In the cytoplasm and are specialized membrane-bounded structures.
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Cystol
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Organic molecules and ions in solution of the cytoplasm
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Plasma Membrane
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Encloses a cell and separates its contents from its surroundings
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Cell Wall
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A rigid cell wall that surrounds the plasma membrane. It has no distinct interior compartments
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Ribosomes
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Found in prokaryotic cells and carry out protein synthesis
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Endomembrane System
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Weaves through the cell's interior and by numerous organelles
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Panspermia
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1. The earth formed as a hot mass of molten rock 4.5 BYA 2. Life arose from these early waters 3. Life may have infected the earth from another planet
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Reducing Atmosphere
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Miller and Urey did an experiment that reproduced the early atmosphere and small organic molecules were in the experiment
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Polymers
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Form through a concentration through: 1. Evaporation of solution near hot springs 2. Freezing and concentration of solution in cold environments 3. Absorption onto charged mineral surfaces
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Proteinoid Microspheres
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1. Are selectively permeable 2. Have different metabolism inside compared to outside 3. Grow 4. May move if it has ATP 4. No heredity materiel
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Microfossils
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Fossilized forms of microscopic life
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Stromatolites
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Mats of cyanobacteriel cells that trap minerals
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Biomarkers
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Organic molecules of biological origin
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Prokaryotic Cells have:
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1. Genetic materiel in the nucleoid 2. Cytoplasm 3. Plasma membrane 4. Cell wall 5. Ribosomes 6. No membrane-bound organelles 7. No membrane-bound nucleus
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Bacteria
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1. Most abundant organisms on earth 2. Take nitrogen from the air, and recycle Carbon and Sulfur 3. Do a lot of the world's photosynthesis 4. Causes diseases 5. Diverse
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Archaea
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Prokatyotes that are more closely related to eukaryotes
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Archaea: Methanogens
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Use H2 to reduce CO2 and swamp gas, they are anaerobics that live in swamps
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Archaea: Extemophiles
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Thermophiles: High temperatures Halophiles: High salt Acidophiles: Low pH
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Archaea: Nonextreme Archaea
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Grow in same environments as bacteria
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Eukaryotic Cells
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1. Have a membrane bound nucleus 2. Are more complex than prokaryotic cells 3. Divide many cellular functions within organelles and the endomembrane system 4. Have a cytoskeleton for support and to maintain a cellular structure
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4 Eukaryotic Kingdoms
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1. Protista 2. Fungi 3. Plantae 4. Animalia
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Protista
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1. Unicellular with a few multicellular organisms 2. Not monophyletic
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Fungi, Plantae, Animalia
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1. Mostly multicellular organisms 2. Each has a different evolutionary line derived from a unicellular protist
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Compartmentalization
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Allows for more subcellular specialization
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Multicellularity
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Allows for differentieation of cells into tissues
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Sexual Reproduction
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Allows for greater genetic diversity
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Nucleus of a Eukaryotic Cells
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1. Stores the genetic materiel of the cell in the form of multiple, linear chromosomes 2. Surrounded by a nuclear envelope composed of 2 bilayers 3. In the chromosomes, DNA is organized with proteins to form chromatin
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Mitochondria
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1. Organelles present in all types of eukaryotic cells 2. Have metabolism enzymes for transferring the energy within macromolecules to ATP
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Endosymbiosis
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1. Proposal that eukaryotic organelles evolved through a symbiotic relationship 2. One cell covers over a second cell and a symbiotic relationship developed 3. Mitochondria and chloroplasts are though to have evolved this way
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Darwin
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Evolution is descent with modification
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Evolution
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Changes through time. 1. Species accumulate difference 2. Descendents differ from their ancestors 3. New species arise from existing ones
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Natural Selection
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Proposed by Darwin as the mechanism of evolution 1. Individuals have specific inherited characteristics 2. They produce more surviving offspring 3. The population includes more individuals with these specific characteristics 4. The population evolves and is better adapted to its present environment
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Godfrey Hardy and Wilhelm Weinberg
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The original proportions of the genotypes in a population will remain constant from generation to generation as long as five assumptions are met
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Hardy-Weinberg Principle 5 assumptions
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1. No mutation takes place 2. migration of genes 3. Random mating is occurring 4. A large population size 5. No selection (these conditions are rarely met)
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Non Hardy-Weinberg Populations:
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1. Mutation 2. Gene Flow 3. Non-Random Mating 4. Genetic Drift 5. Selection
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Mutation
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A change in a cell's DNA 1. Has little effect on the Hardy-Weinberg proportions of common alleles. 2. Ultimate source of genetic variation
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Gene Flow
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A movement of alleles from one population to another 1. Can be a powerful thing for change 2. Or can homogenize the allele frequencies
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Genetic Drift and ex.
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In small populations, individuals that carry a particular allele may leave more descendants than other individuals leave, just by chance. Over time, a series of chance occurrences can cause an allele to become more or less common in a population. ex. Anolis lizards and dewlap color
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Founders Effect
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Allele frequencies change as a result of the migration of a small subgroup of population.
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Bottleneck Effect
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The bottleneck effect is a change in allele frequency following a dramatic reduction in the size of a population.
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Artificial Selection
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A breeder mates with another of their kind for desired characteristics
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Natural Selection
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Environmental conditions determine which individuals in a population produce the most offspring
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Natural Selection 5 Parts:
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1. Variation exists in populations (there are giraffes with long necks and giraffes with short necks)
2. Over-production of offspring (more offspring than the environment can support) (the giraffes with long necks are reproducing rapidly) 3. Competition (the giraffes with long necks are able to reach the food) 4. Differential survival (adaptations: successful traits) (they can reach the food, therefore the ones with short necks slowly begin to die off) 5. Differential reproduction (adaptations become more common in population) (the long necks begin to reproduce and are more common in the population |
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Fitness
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A phenotype with greater fitness increases it's frequency in a population (fitness meaning most well adapted/fit to environment, most fit given a value of 1)
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Fitness is a combination of:
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1. Survival 2. Mating success 3. Number of offspring per mating that survive
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Oscillating Selection and ex.
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Selection favors one phenotype at one point, and a different phenotype at another time ex. Galapagos Islands ground finches: Wet conditions favor big beaks, dry conditions favor small beaks
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Hertozygote advantage
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Keeps harmful alleles in a population ex. Sickle Cell Anemia, homozygous recessive phenotype: you have severe anemia
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Homozygous Dominant Phenotype
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No anemia; you can get malaria
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Heterozygous Phenotype
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No anemia; You will not get malaria
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Disruptive Selection and ex.
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When individuals at the outer ends of the curve have higher fitness than individuals near the middle of the curve (eliminates intermediate types) Ex. A population of birds might split into two groups one with smaller beaks and one with large beaks depending on the sides of the seeds.
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Directional Selection and ex.
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When individuals at one end of the curve have higher fitness than individuals in the middle or at the end (Eliminates one extreme from all the phenotypes) ex. Negative phototaxis in Drosophila) Food affecting individual fitness
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Stabilizing Selection and ex.
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When individuals near the center of the curve have higher fitness than individuals at either end (eliminates both extremes) ex. The mass of human infants at birth
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High Predation Environment
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Males display dark colors, tend to be small, and produce at a younger age
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Low Predation Environment
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Males display bright colors, have a larger number of spots, and tend to be more successful at defending their territories
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Pleiotropy
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Set limits on how much a phenotype can be altered
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Evidence of natural selection Peter and Rosemary Grant with ground finches
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Found beak depth variation among members of the population, and the average beak depth changed from one year to the next in a predictable fashion. Droughts: Birds with deeper, more powerful breaks survived better Normal rains: Average beak depth decreased its original size
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Biston Betularia
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Peppered moths, when the environment changes natural selection often favors different traits in a species. 1. Light gray with black specks became jet black. 2. Black ones have the dominant allele, and this allele was rare
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J. W Tutt
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Hypothesized that light-colored moths declined because of predation and light moths were easily seen by birds or darkened into sooty trees
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Bernard Kettlewell
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Tested the moth hypothesis. 1. Dark tree trunks = more dark-colored moths survive 2. Light tree trunks = more light-colored moths survive 3. When environmental conditions reverse, so does the selection pressure
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Industrial Melanism
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Phenomenon in which darker individuals are the strongest over lighter ones
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Pollution control
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Resulted in lichen growing on trees and bark color being lighter again. Light-colored pepper moths are now dominant in the population because of the industrial revolution
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Fossil Evidence of Evolution
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Researchers have found more than 20 fossils that document the evolution of modern whales from ancestors that walked on land. We can infer that ancient whales can be linked back to ancient artiodactyls (mammals that walk on land). The limb structure slowly changed over time and overtime reduced the hind limbs being used. Because the modern whales spend their time swimming in the ocean, they have no need for the hind limbs but this is why they are still born with the slits for the hind limbs.
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Anatomical Evidence of Evolution
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Homologous bones support the differently shaped front limbs of modern vertebrates. The front limbs of reptiles and birds are very similar to each other. This similarity indicates that the common ancestor of reptiles and birds lived more recently than the common ancestor of reptiles, birds, and mammals
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Molecular Evidence of Evolution
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At the molecular level, the universal genetic code and homologous chromosomes provide evidence of common descent. ex. Cytochrome c
This is a homologous protein that functions in cellular respiration. Similar versions of Cytochrome C are found in almost all living cells. |
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Absolute Dating
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Age of fossils is estimated by rates of radioactive decay
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Relative Dating
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Position of the fossil in the sediment
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Half-Life
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The isotope's rate of decay
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Vestigial Structures
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Vestigial structures are inherited from ancestors but have lost much or all of their original function due to different selection pressures acting on the descent. ex. the appendix
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Biogeography
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The study of the geographic distribution of species, some plants and animals have similar appearance but they are not near each other
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Convergent Evolution
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The independent development of similar structures in organisms that are not directly related. It is usually seen in animals and plants that live in similar environments
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Marsupials
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Young are born in an immature condition and held in a pouch until they develop
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Placentals
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Young are not born until they can safely survive in the external environment
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Darwin noted on his voyage that:
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1. Islands were often missing plants and animals common on the continents 2. Species on the islands often diverged from relatives from other continents 3. Island species usually were more closely related to species on nearby continents
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Darwin concluded that:
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1. Species arrive on islands by spreading across the water 2. Spreading across from nearby areas is more likely than distant sources 3. Species that can fly, float, or swim can inhabit islands 4. Colonizers often evolve into many species
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The concept of species must have 2 phenomena:
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1. The distinctiveness of species happens together at a single location 2. The connection that exists among different populations belonging to the same species
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Speciation
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The process by which new species arise (one species turns into 2 species) either by: 1. Transformation of one species into another 2. The splitting of one ancestral species into two descendent species
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Sympatric Speciation
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The differentation of populations within a common geographic area into species and occurs without geographic isolation. Instantaneous speciation through polyploidy
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Species that happen together:
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1. Are distinctive things 2. Are phenotypically different 3. Use different parts of their habitat 4. Behave differently
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Population
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A group of individuals, usually a single species, occupying a given area at the same time
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Subspecies
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Withing a single species, individuals in populations that happen in different areas may be different from one another
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Earnst Mayr's Biological Species Concept
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Members of a population mate with each other and produce fertile offspring
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Reproductive Isolation
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When populations become reproductively isolated, they can evolve into two separate species, or a population whose members do not mate with each other or cannot produce fertile offspring. Reproductive isolation can develop in a variety of ways, including behavioral isolation, geographic isolation, and temporal isolation.
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Ecological Isolation
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Using different portions of the environment and they do not encounter each other ex. Lion and tiger
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Behavioral Isolation
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Two populations are capable of interbreeding develop differences in courtship rituals or other behaviors. ex. eastern and western meadowlarks
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Pheromones
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Chemical signals
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Temporal Isolation
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When two or more species reproduce at different times. ex. orchids living in the same rain forest
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Mechanical Isolation
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Structural differences between species prevent mating
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Prevention of gamete fusion
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Gametes of one species functions poorly with the gametes of another species or within the reproductive area of another species
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Postzygotic Isolation
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Prevents normal development into reproducing adults
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Hybridization
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Mating between two different species with a zygotet being formed
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Hybrids and ex.
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1. Do not develop into adults or fertile adults ex. mule
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Cladogenesis
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One ancestral species becomes divided into two descendant species
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Reinforcement
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Incomplete isolating mechanisms are reinforced by natural selection until they have completely worked
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Random Divergence
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May affect traits responsible for reproductive isolation; speciation may occur
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Anolis Lizards
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1. Ability to see dewlap depends on color and environment 2. Light color: reflects light in dark forest conditions 3. Dark color: More visible in bright glare of open habitats
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Polyploidy
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1. Reproductively isolated from all other members of it species 2. Individuals that have more than two sets of chromosomes 3. Plants with 4 sets of chromosomes can survive, but not be diploid individuals
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Allopolyploidy
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1. Two species hybridize 2. This results with one offspring having one copy of the chromosomes of each species 3. They are infertile and cannot reproduce with either species 4. They can reproduce asexually 5. Can become fertile if chromosomes spontaneously doubled
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Human Evolutionary Future
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1. Natural selection as an engine of evolutionary change 2. Human changes of our own gene pool
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Adaptive Radiations
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Closely related species that have recently evolved from a common ancestor by adapting to different parts of the environment
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Adaptive radiation occurs:
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1. In an environment with few other species and many resources 2. Galapagos islands 3 Catastrophic event leading to extinction of other species
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Key Innovation and ex.
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Evolved within a species allowing it to use resources or other things in the environment that were previously not accessible. It allows descendent species to adapt to new parts of the environment ex. Evolution of lungs in fish
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Character Displacement
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Natural selection in each species favors those individuals that use resources not used by other species 1. Greater fitness 2. Trait differences in resource use will increase in frequency over time 3. Species will diverge
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Alternative
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1. Adaptive radiation happens through repeated instances of sympatric speciation 2. Produces a set of species adapted to different habitats
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Adaptive Radiation Case 1: Hawaiin Drosophila
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1. 1,000 species of Drosophilla were found on Hawaiin islands 2. Diversity of morphological and behavioral traits 3. Empty niches resulted in fruit flies such as parasites
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Adaptive Radiation Case 2: Darwin's Finches
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1. Ancestors were exposed to different selective pressures 2. Geographic isolation on many islands 3. Diverse population and some evolved into separate species 4. Occupy different habitats
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Ground Finches
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1. Feed on seeds 2. Size of beak relates to size of the seed they eat
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Tree Finches
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1. All eat insects 2. One species uses a tool to get insects
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Vegetarian Finch
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Eats buds from branches
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Warbler Finches
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Eats insects from leaves and branches
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Adaptive Radiation Case 3: Lake Victoria cichild fishes
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1. Was home to over 300 species of cichlid fish until recently 2. Recent radiation 3. Colonized from the Nile River 4. Changes in water level encouraged species formation 5. Lake dry down 14,000 years ago
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Gradualism
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The accumulation of small changes
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Punctuated Equilibrium
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1. Long periods of no activity followed by rapid change 2. Proposed by Niles Eldridge and Stephen Gould in 1972
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Adaptation
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A genetic variation that is favored by selection and is clear as a trait that provides an advantage to an organism in a particular environment.
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Random Fertilization
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1. Each gamete is 1 of 8 million possibilities due to independent assortment 2. Adds to genetic variation because any sperm can fuse with any unfertilized egg
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