Biology Practical #2

• What is Evolution

  -Change in heritable traits over time

  -Described by Charles Darwin as decent w/ modification

  -All life on Earth shares a common ancestor

  -Descendants of this ancestor together comprise Earth's biodiversity

  -All life on Earth is distantly related
• What is a Theory?

  -Mature, coherent body of interconnected explanations based on reasoning and evidence.

  • Parts of theory can always be discarded in light of new data
  • Doesn't stand or fall based a single critical test (as a hypothesis does)
• What is Catastrophism?

  -Tied to Christianity

  -Earth's current landscape is due solely to catastrophic & supernatural events of the past, at the time of the creation of the Earth

  -Features, like mountains, were formed by sudden and abrupt changes.
• What is Uniformitarianism?

  -Earth undergoing uniform cycles of change like it did in the past (gradual change)

  -Landscapes form over long periods of time through gradual processes, typically gradually through humans, but ultimately leading to large changes over time

  -Process of change happens the same way that it have happened in the past.

  -Mountain uplift, erosion, valley formation, etc.
• What is Lamarckian Evolution?

  -Changes through use and disuse (change occurs during organism's lifetime)

  -Changes passed onto offspring

  -Based on erroneous (inaccurate) explanation of inheritance
• Charles Darwin

  -Interested why there is so much biodiversity

  -Not the first to notice organisms change over time

  -Proposed mechanism for change (1859)

  • Natural Selection
• What is Evolution by Natural Selection?

  The process whereby individuals better adapted to their environments tend to better survive and reproduce, changing the genetic makeup of populations over time.
• What are the 4 Pillars of Natural Selection?

  1)Variation - Individuals within a population have traits that vary.

  2)Inheritance - Some traits are passed onto offspring

  3)High Rate of Population Growth - More offspring are produced than might survive in a generation

  4)Differential Survival and Reproduction - Individuals who survive and go on to reproduce, or reproduce the most, are those w/ most adaptive traits.
• What is Artificial Selection?

  Process by which humans identify particular observable traits and select breeding pairs to produce offspring which reflect those desired phenotypes
• What is Sexual Selection?

  -Selection which acts on an organism's ability to obtain and/or successfully copulate with a mate

  -Darwin felt natural selection alone could not account for certain adaptations (Ex: Long tail feathers hinder survival)
• What is Modern Evolutionary Synthesis?

  -(1930-1950)

  -Mixed Darwinian Evolutionary Theory w/ Genetics

  -Allowed for additional mechanisms
• What are the multiple mechanisms of evolution?

  -Mutation

  -Genetic Drift

  -Gene Flow

  -Non-Random Mating

  -Selection
• What is Mutation?

  -A change in DNA

  -New alleles are introduced into the population
• What is Genetic Drift?

  -Random variation in the relative frequency of alleles in a population

  -Alleles can become either fixed or lost by chance

  -Most impactful in small populations
• What is Gene Flow?

  -Migration

  -Transfer of genetic material from one population to another
• What is Non-Random Mating?

  -Individuals prefer mates with particular characteristics.
• What is Selection?

  -Differential survival and reproduction of certain genotypes by means of natural or artificial factors.
• What us the Hardy-Weinberg Equilibrium?

  -A mathematical model and hypothetical situation that describes control conditions for evolution (a basis for comparison)
• What are the 4 assumptions, if met, proves that population is NOT evolving? (Slide Version)

  1)There is no differential reproductive success among individuals

  2)The population is large, so random changes in allele frequencies are trivial

  3)There is no net immigration or emigration of individuals

  4)There are no new mutations

  • Evolution is occuring if any of the above assumptions are violated.
• 4 assumptions that, if met, prove population is NOT evolving? (Simple Version)

  • Everyone has an equal chance of having babies
  • In a big group, random changes don't really matter because there are so many individuals
  • Nobody new is coming in, and nobody is leaving
  • There are no new changes in the genes
• What is the equation for Hardy-Weinberg Equilibrium?

  p^2 + 2pq + q^2 = 1

  p^2 = frequency of homozygous dominant genotype

  2pq = frequency of heterozygous genotype

  q^2 = frequency of homozygous recessive genotype
• What are the two different temporal scale perspectives of evolution?

  -Microevolution

  -Macroevolution
• What is Microevolution?

  -Evolutionary change within populations

  -A change in gene frequency within a population

  -Can occur over short periods of time from generation to generation
• What causes Microevolution?

  -Isolation

  -Genetic Drift

  -Non-Random Mating

  -Mutation

  -Selection
• What is Macroevolution?

  -Interspecific variation

  -Major trends and Transformations in evolution over long periods of time (geologic time)

  -Studies of the fossil record and living organisms
• What causes Macroevolution?

  -Mutation

  -Gene Flow

  -Genetic Drift

  -Natural Selection

  + 3.8 billion years

  = Macroevolution
• What are the different patterns of Evolution?

  -Convergent Evolution

  -Adaptive Radiation

  -Coevolution
• What is Convergent Evolution?

  -Similar adaptations evolve independently in different lineages because of exposure to similar selection pressures.

  -Similarities not due to close relatedness, but rather, similar environments.
• What is Adaptive Radiation?

  -Diversification of a group of organisms into forms filling different ecological niches

  
• What is Coevolution?

  -Two or more species affect each other's evolution

  -Likely to occur when different species have close ecological interactions with one another

  • Predator/prey
  • Parasite/host
  • Competition
  • Mutualism
• What are Evolutionary Misconceptions?

  -The process of evolution results in perfect organisms, flawlessly adapted to their environments

  -Evolution is a linear process, beginning with simplicity and ending with complexity

  -Organisms want or need to evolve

  -Life is survival of the fittest Evolution only occurs slowly

  -Evolution occurs at the level of the individual

  -Evolution is not observable or testable

  -Evolution does not occur in humans

  -Organisms evolve from one another in a continuum
• What is this?

  Domain Eukarya, Lineage Opisthokonta, Phylum Porifera

  
• What is this?

  Domain Eukarya, Lineage Opisthokonta, Phylum Cnidaria

  
• What is this?

  Domain Eukarya, Lineage Opisthokonta, Phylum Platyhelminthes

  
• What is "Levels of Organization?"

  Animal bodies are composed of multiple cells of several types, each type performing a specific function.
• What lowest level of organization to highest level of organization?

  Cell, tissue, organ, organ system, organism.
• What are Germ Layers?

  Germ layers are the primary layers of cells that form during the embryo development -> adult structures come from these initial layers.
• What is a Protostome?

  Blastopore becomes mouth (ex. Insects, earthworms)
• What is a Deuterostome?

  Blastospore becomes anus (ex. Humans, sea stars)
• What level of organization does Phylum Porifera have?

  Cellular level of organization, no tissures

  • Sponges are the least complex animals