Biology Study Notes

Protists

  • Protists are a diverse group of mostly unicellular eukaryotic organisms that don't fit neatly into other kingdoms.
  • They are classified based on features like cell structure, nutrition, movement, and reproduction.

Human Impact on Plants

  • Human activities such as pollution, deforestation, and climate change are harmful to plants.
  • Actions to reduce negative effects:
    • Protecting habitats.
    • Reducing pollution.
    • Planting trees.

Genetic Diversity

  • Variability among organisms, usually referring to individuals of the same species.

Binomial Nomenclature

  • The formal system of naming species using two Latin words:
    • Genus name (capitalized).
    • Species name (lowercase).
  • Example: Homo sapiens is the scientific name for humans.

Dichotomous Key

  • A tool used to identify organisms or objects by answering a series of yes/no or either/or questions.
  • These questions lead the user step-by-step to the correct identification.

Phylogenetic Tree

  • A diagram that shows the evolutionary relationships among various biological species or entities.
  • Relationships are based on similarities and differences in genetic or physical characteristics.
  • It resembles a tree with branches indicating common ancestors and points of divergence.

Taxonomy

  • The naming, describing, and classifying of organisms, including all plants.

Levels of Classification (Most Inclusive to Least Inclusive)

  • Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Virus

  • A microscopic infectious agent that can only replicate inside the living cells of a host organism.
  • Composed of genetic material (DNA or RNA) enclosed in a protein coat and sometimes a lipid envelope.
  • Viruses are not considered living organisms because they cannot carry out life processes on their own.

Kingdoms and Phyla

  • Be able to compare/contrast each of the kingdoms and phyla. (Consult your textbook and class notes for specific details on each.)

Scientific Names

  • Scientific names were developed to avoid confusion caused by different common names.
  • They provide a universal, consistent way for scientists around the world to identify and communicate about each species accurately.

Plant Adaptations to Land

  • Stomata (pores on leaves):
    • Allow gas exchange (CO<em>2CO<em>2 in, O</em>2O</em>2 out) while minimizing water loss.
  • Vascular tissue (xylem & phloem):
    • Transports water, nutrients, and sugars throughout the plant, allowing growth away from water sources.
  • Roots:
    • Anchor the plant in the soil and absorb water and minerals from the ground.
  • Lignin in cell walls:
    • Provides structural support, allowing plants to grow upright and reach sunlight.
  • Pollen:
    • Enables fertilization without the need for water by transporting sperm via wind or animals.
  • Seeds:
    • Protect and nourish the embryo.
    • Allow it to survive harsh conditions and disperse over distances.
  • Leaves:
    • Increase surface area for photosynthesis.
    • May have specialized shapes to conserve water.
  • Flowers (in angiosperms):
    • Attract pollinators to improve chances of fertilization.
  • Fruit (in angiosperms):
    • Protects seeds and aids in their dispersal by animals, wind, or water.

Dichotomous Key Example

  • Using the following information about three species of lilies, a dichotomous key can be created:
    • Lilium henryi has golden orange flowers.
    • Lilium leucanthemum has white trumpet flowers.
      • The outside of the flower, the "reverse," is a dark chocolate raspberry color.
    • Lilium regale has white trumpet flowers with a pink reverse.

Dichotomous Key

1a. Flowers are golden orange in color: Lilium henryi
1b. Flowers are white trumpet-shaped: go to 2
2a. The reverse of the flower is dark chocolate raspberry: Lilium leucanthemum
2b. The reverse of the flower is pink: Lilium regale

Fungi and Plants

  • Biologists originally placed fungi with the plant kingdom because both are eukaryotic and can reproduce with spores.

Angiosperms vs. Bryophytes

  • Angiosperms:
    • Advanced, vascular plants.
    • Reproduce with flowers and seeds.
  • Bryophytes:
    • Simpler, nonvascular plants.
    • Rely on spores and need moist environments to reproduce.

Fungi vs. Plants

  • Similarities:
    • Both are eukaryotic.
    • Both can reproduce with spores.
  • Differences:
    • Fungi are heterotrophs that absorb nutrients and have chitin in their cell walls.
    • Plants are autotrophs that make their own food through photosynthesis and have cellulose in their cell walls.