Connect

Connect

1. mutations: any heritable change in the genetic material

   • deleterious: have a harmful effect on organism
   • neutral: have little or no effect
   • advantageous: improve the carrier's chance of survival or reproduction

2. population: all individuals of a given species that live and reproduce in a particular place

   • allele frequencies: the relative frequency of an allele at a particular locus in a population
     • fixed: a population exhibits only one allele at a particular gene
   • genotype frequency: proportion in a population of each genotype
   • Eukaryotes
     • Photosynthetic Eukaryotes
       • Oxygenic: oxygen-producing; when oxygen is limited/absent, other electron donors such as H2S are available for photosynthesis and are used by photosynthetic microorganisms
     • All respiration in eukaryotic cells is aerobic (oxygen using)
       • Aerobic: where oxygen is absent; other electron acceptors can be used for respiration
         • Organisms that use these alternative electron donors and electron acceptors are bacteria and archaea

3. Hardy Weinberg Equilibrium

   • 1.) There is no difference in the survival and reproductive success of individuals.
   • 2.) The population is sufficiently large to prevent sampling errors
   • 3.) Populations are not added or subtracted from by migration
   • 4.) There is no mutation
   • 5.) Individuals mate at random

4. Natural Selection: Results in allelle frequencies changing from generation to generation according to the allele's impact on the survival and mutation of individuals

   • Positive selection: Increases the frequency of an advantageous allele
   • Negative selection: Decreases the frequency of a deleterious allele
   • Stabilizing selection: maintains the status quo
   • Balancing selection: acts to maintain two or more alleles in a population
     • Heterozygous advantage: Ensures both alleles remain in the population at intermediate frequencies
   • Directional selection: leads to a change in trait over time
   • Sexual selection: promotes traits that increase an individual's access to reproductive opportunities
     • Intersexual selection:focuses on interactions between male and female
   • Intrasexual selection: focuses on interactions between individuals of one sex
   • Artificial selection: practiced and controlled by humans; the competitive element is removed
   • Disruptive selection: Operates in favor of extremes and against immediate forms
   • Taxonomic Groups:
     • Monophyletic: all members share a single common ancestor that is not shared with any other species or group of species
     • Paraphyletic: Descendants of a common ancestor
     • Polyphyletic: Share traits that evolved independently by convergent evolution
     • Homologous: Characters that are similar because of a descent from a common ancestor
     • Analogous: Similarities due to independent adaption by different species
       • Result of convergent evolution
     • Character: anatomical, physiological, or molecular features that make up an organism
       • Character states: observed conditions
     • Synapomorphies: shared derived character
       • Cladistics: building a phylogenetic tree based on synapomorphies
   • Parsimony: The simpler of two hypotheses
     • Simplest tree= one with least changes
   • The Fossil Record
     • Trace fossils: fossils of trails rather than body parts
     • Molecular fossils: Organisms
       • Preserves some biological history
     • Geological timescale: The series of time divisions that mark Earth's long history
     • Radiometric dating: the measure of the radioactive decay of the isotope Carbon-14
     • Half-Life: the measurements that indicate how much radioactive decay of C-14 will happen over time
     • Mass extinctions: eliminated ecologically important taxa; provides evolutionary opportunities
   • Eukaryotic Cells
     • Haploid cells: Carry one set of chromosomes
       • Diploid Cells: Result of the sexual fusion of two haploid cells; carry two sets of chromosomes
       • Zygote: Formed by single-celled eukaryotes; also a diploid cell
     • Symbiont: an organism that lives in closely evolved association with another species
       • Symbiosis: The association by which symbionts are formed
       • Endosymbiosis: One partner lives within the other
     • Choanoflagellates: Closely related to animals; mostly unicellular protists; characterized by a ring of microvilli
     • Amoebozoa: A group of eukaryotes with amoeba-like cells
     • Archaeplastida: Most conspicuous and diverse eukaryotes
     • Stramenopila: unicellular organism
       • giant kelps, algae, protozoa, free living cells, and parasites
         • have unusual flagellum that bears two rows of stiff hairs
     • Alveolata: diverse group that includes photosynthetic and heterotrophic species
       • united by the feature of small vesicles
     • Microfossils: only formed by organisms with a cytoskeleton and endomembrane system

5. Calculating allele frequencies

   • 2x(number of homozygotes)+ (number of heterozygotes)

6. Genetic Drift: the random change in allele frequencies from generation to generation

   • Bottleneck Effect: occurs when an originally large population is reduced to just a few individuals
   • frequences go up or down by chance
     • Founder event: When a few individuals atart a new populatiom
       • Example: Individuals colonize an island; the allele frequencies are randomly changed and genetic variation is lost
     • has a large effect in small populations

7. Molecular Evolution: populations have diverged genetically

   • Molecular clock: the correlation between the time for which two species have been evolutionarily separated and the amount of genetic divergence between them
     • Pseudogene: a gene that is no longer functional

8. Migration: the movement of individuals from one population to another

   • Gene flow: movement of alleles from one population to another

9. Speciation

   • VIcariance: Geographic barrier arises within a single population, separating it into two or more isolated populations
   • DIspersal: Some individuals colonize a distant place, far from the main source population
   • Peripatric speciation: few individuals from a mainland population disperse to a new location remote from the original population and evolve separately.
   • Co-speciation: a process in which two groups of organisms speciate in response to each other and at the same time
   • Instantaneous speciation: caused by hybridization between two species in which the offspring are reproductively isolated from both parents
   • Allopatric: geographically separated

10. Hybridization: different species are capable of exchanging genes with other species in their genera

    • Hybrid offspring: populations are reproductively isolated from a closely related species
      • In one location the two groups may be isolated from each other;
      • while in other areas they interbreed.

11. Behaviorally isolated: individuals mate only with other individuals based on specific courtship

    • Gametic Isolation: incompatibilities between two gametes of two different species
      • Mechanical incompatibility: physical traits prevent reproduction between species
    • Temporal Isolation: pre-zygotically isolated; example: do not show up at the same time in a year
    • Geographic/ecological isolation: isolated in space
    • Partially reproductively isolated: try to cross members of two populations, but not yet diverged far enough for full reproductive isolation

12. Carbon Cycle: the path of carbon as it moves between organisms, the atmosphere, rocks, soil, and the ocean

13. Bacteria

    • Plasmids: small circles of DNA that replicate independently of the cell's circular chromosome.
      • Conjugation: commonly transfers plasmids from one cell to another, spreading novel genes throughout a population
        • Transformation: DNA released to the environment by cell breakdown can be taken up by other cells
    • Peptidoglycan: a complex polymer of sugars and amino acids
    • Horizontal gene transfer: bacteria obtain new genes from distant relatives; a major source of genetic diversity
      • Transduction: *HGT for Viruses*: viruses released from their host cell go on to infect others, bringing host-derived genes

14. Cyanobacteria

    • Anoxygenic: do not produce oxygen; use electron donors such as H2S, Fe2+, AsO3-
      • Where O2 is present, compounds oxidize quickly/ not available for photosynthesis

15. Fermentation: involves partial oxidation of carbon compounds to molecules that are less oxidized than CO2; does not require an external electron acceptors

16. Being Multicellular

    • Bulk Flow: any means by which molecules move through organisms at rates beyond those possible by diffusion across a concentration gradient
      • Distributes nutrients throughout the body
        • Intestinal cells absorb organic molecules required for respiration
          • The active transport through bloodstream that distributes these molecules over large distances
      • Endocrine signaling molecules such as hormones
      • Complex multicellular organisms have structures specialized for bulk flow
    • Diffusion
      • Only effective over short distances
      • Animals achieve large size by circumventing limits imposed by diffusion
    • How to build a multicellular organism
      • Complex multicellularity requires adhesion between cells
        • Complex multicellularity requires communication between cells
          • Complex multicellularity requires genetic program for coordinated growth and cell differentiation
    • Plants versus Animals
      • Cell walls shaped patterns of growth and development in plants
        • Walls made of cellulose provide structural support to its cells
      • Animal cells can move relative to each other
        • Blastula: formed of a single layer of undifferentiated cells
          • Gastrula: Multiple layers of blastula
            • Gastrula bring new populations of cells into direct contact with one another
    • Evolution of Complex Multicellularity
      • Fossil evidence of complex multicellular organisms is first observed in rocks deposited 575-555 million years ago
      • Oxygen is necessary for complex multicellular life
      • Land plants evolved from green algae that could carry out photosynthesis on land
      • Regulatory genes played an important role in the evolution of complex multicellular organisms

17. Land plants share many cellular features with green algae

    • Organisms with complex multicellularity produce three dimensional bodies with differentiate tissues and organs
      • Plant cells share many features with cells of green algae
        • Both contain chloroplasts with chlorophyll; include a large membrane bound vacuole that stores ions, metabolites, and water
          • Contain a cellulose-containing wall that surrounds almost every cell

18. Uptake of Water and Nutrients

    • Plants obtain nutrients from the soil
    • Nutrient uptake by roots is highly selective
      • Requires energy: energy is required to move nutrients across the cell membrane

19. Growth and nutrition

    • Hyphae permit fungi to explore their environment for food resources

20. Respiratory Gas Exchange

    • Many aquatic animals breathe through gills
    • Insects breathe air through tracheae
      • Most terrestrial vertebrates breathe by tidal ventilation of internal lungs