Unit Three Biology

Subdecks (1)

Cards (63)

  • Mitosis (somatic cell division):
    • one parent cell gives rise to 2 identical daughter cells
    • asexual reproduction
    • maintains chromosomes (diploid) number
    • mitosis is the nuclear division
    • cytokinesis is a cytoplasmic division
    • occurs in billions of somatic cells each day
    • needed for tissue repair, maintenance, and growth
  • Meiosis (reproductive cell division):
    • one parent cell gives rise to 4 identical/non-identical daughter cells
    • sexual reproduction
    • reduces chromosome number in half =(haploid #)
    • egg and sperm cell production = gametes
    • fusion of egg and sperm results in a zygote. When this single-celled zygote divides mitotically it becomes an embryo
  • Sexual Reproduction- produces genetic diversity among offspring, increasing the chances that some offspring survive in changing environments
  • chromosome: a long, coiled DNA molecule that carries genetic information
  • autosome: a chromosome that is not a sex chromosome
  • sex chromosome: a pair of chromosomes that determine the sex of an individual
  • homologous pair: two chromosomes that are identical in length and have the same number of chromosomes
  • sister chromatids: two identical chromosomes that are joined by a centromere
  • genes: the basic unit of heredity, consisting of a segment of DNA that codes for a particular protein
  • alleles: different versions of a gene that are inherited from parents and are passed on to offspring
  • Artificial Selection: The process by which humans selectively breed organisms to produce desired characteristics.
  • Allele Frequency:
    # of copies of an allele
    Total # of alleles for the same gene in the population
  • Adaptations: A feature of an organism that helps it survive and reproduce in its environment.
  • Gene Pool: The total number of alleles in a population of a species.
  • Fitness: The ability of an organism to survive and reproduce in its environment.
  • Hardy-Winberg Equilibrium: unlikely situation in which allele frequencies do not change between generations
  • Allele Frequencies:
    p+p+q=q=11p2+p^2+2pq+2pq+q2=q^2=11
    p is the frequency of the dominant allele and q is the frequency of the recessive allele
  • Genetic Drift: occurs purely by chance. It is most common in small populations
  • Founder Effect: when only a few individuals establish a new population, the allele frequency might change.
  • Population Bottleneck Effect: occurs if a disaster drastically reduces the size of a population
  • gene flow: moves alleles between populations
  • Directional Selection: a mode of natural selection in which a single phenotype is favored, causing the allele frequency to shift in one direction continuously
  • disruptive selection: extreme phenotypes are favored over an intermediate phenotype
  • Stabilizing selection: an intermediate phenotype is favored over the extreme phenotypes
  • Immigration: the movement of individuals into a population
  • Emigration: the movement of individuals out of a population
  • Survivorship curves: show the proportion of surviving individuals at each age
  • Type 1 Survivorship Curve: A species that invests much energy in caring for young, has low death rates early in life. Most individuals survive to reproduce
  • Type II survivorship curve: have an approximately equal probability of dying at any age
  • Type III Survivorship Curve: a species that invests little energy into raising their young, resulting in a high death rate among offspring. Few individuals survive to reproductive age
  • G=G=rNrN(exponential growth)

    G= growth rate
    r= per capita rate of increase
    N= the initial size of the population
  • G=G=rN((KN)/K)rN((K-N)/K)(population growth)

    G= growth rate
    r= per capita rate of increase
    N= the initial population size
    K= carrying capacity
  • Opportunistic Life History:
    • high reproduction rate
    • many offspring
    • each offspring receives little parental care
    • low survival rate for juveniles
    • early reproductive maturity
    • type III survivorship curve
  • Equilibrium Life Theory:
    • low reproduction rate
    • few offspring
    • each offspring receives extensive parental care
    • high survival rate for juveniles
    • late reproductive maturity
    • Type I survivorship curve