evolution

• mutations are not always bad
• The process by which new species arise is called speciation
• Properties of life:

  • Order
  • Evolutionary adaptation
  • Response to the environment
  • Reproduction
  • Growth and development
  • Energy processing
  • Regulation
• Adaptation is an inherited trait that helps the organism survive/reproduce in a particular environment
• Every organism has a common ancestor
• Two levels of evolution:

  • Large scale results in an evolutionary tree over years
  • Small scale involves a change in genetic composition, a change from every generation, and a change in allele frequencies
• Evolution is studied by collecting and analyzing data from a group of taxa, including DNA and morphological traits
• Processes of evolutionary change include natural selection, genetic drift, gene flow, mutation, and non-random mating
• Evolution is a historical perspective:

  • Scala naturae = scale of nature
  • Traditional view (species are fixed and perfect from the Old Testament)
  • Binomial classification (a system based on similarity)
  • Fossil evidence of change over time
  • Jean Baptiste Lamarck proposed that fossils are ancient versions of modern species
  • Charles Darwin observed examples of adaptation and proposed natural selection as the mechanism for evolution
• Natural selection:

  • In population display inherited variations
  • Species get different variations for selection
  • Overproduction of offspring leads to more genes being passed down
  • Reproductive success = fitness
  • Fitness is the ability to leave genes for the next generation
  • Competition for resources leads to the accumulation of favorable traits (adaptation) over generations
  • Natural selection depends on time and place
• Evidence of evolution:

  • Direct observation
  • Phylogeny (a drawing that shows a hypothesis of evolution like a family tree)
  • Homology (analyzing similarities between organisms with common ancestry)
  • Vestigial traits (a useless or rudimentary version of a body part that has an important function in other closely related species)
  • Fossil record
• Mechanics that can cause the evolution of populations:

  • Evolution happens over time when allele frequencies of a population change
  • Natural selection, genetic drift, and gene flow are important in allele frequency change
  • Genetic variation includes discrete and quantitative characters
  • Phenotype = genotype + environment
  • Only genetically determined parts of the phenotype have an evolutionary impact
  • Sources of genetic variations include mutation, chromosomal rearrangements, and sexual reproduction
• Population genetics:

  • Locus is the location of the gene
  • Allele is a form of a gene
  • A gene pool has all the alleles for all individuals in an interbreeding population
  • Alleles are the form of the gene
  • Frequency is the percentage of an allele at a given locus
  • The Hardy-Weinberg equation describes a non-evolving population
• Modes of speciation:

  • Allopatric speciation involves geographic barriers and divergence of gene pools
  • Sympatric speciation occurs without geographic isolation
  • Polyploid speciation involves extra sets of chromosomes due to accidents during cell division
• Animal form and function:

  • Cephalization
  • Segmentation
  • Common challenges include obtaining oxygen, nutrition, reproduction, fighting infection, and maintaining body temperature
  • Limits range of animal forms based on genetic basis and physical laws
• Levels of organization:

  • Cells → tissues → organs → organ systems
  • Tissues are classified into four main categories: epithelial, connective, muscle, and nervous
• sympatric speciation occurs within the same geographic area
• nervous tissue: neurons and glial cells or glia
• conactive tissue: bone ,blood, loose, Fibrous, cartilage, Adipose
• muscle tissue: Skeletal, smooth, cardiac
• Epithelial tissue: columnar, cubiodal, squamous