Taxonomy

Characteristics of Living Things

  • Unicellular vs. Multicellular

    • Unicellular: One cell that performs all functions.

    • Multicellular: More than one type of cell with different functions (e.g., muscle, reproductive, skin).

  • Prokaryotic vs. Eukaryotic Cells

    • Two types of cells on Earth.

    • Prokaryotic (Early Cell Type)

      • Only bacteria and archaea.

      1. DNA strand, but no nucleus.

      2. No membrane-bound organelles (e.g., Golgi, ER, mitochondria).

      3. Cell coverings are chemically different; cell wall contains peptidoglycans.

    • Eukaryotic (True cell)

      1. DNA contained in a nucleus.

      2. Many types of organelles (chloroplasts, Golgi, ER, etc.).

  • Cell Wall vs. No Cell Wall

    • All organisms are surrounded by a cell membrane, which controls what can enter/leave a cell.

    • Some cells have a cell wall for structure.

      • Animal cells and protists do not have a cell wall.

      • Fungi, plants, and bacteria do.

      • Plant cell walls are made of cellulose, and fungal cell walls are made of chitin.

  • Type of Nutrition

    • Heterotrophs: Breakdown others for food/energy (Animals, fungi).

    • Autotrophs: Make their own food (Plants).

      • Photosynthesis: CO2 + H2O —> C6H12O6 + O2

      • Cellular Respiration: C6H12O6 + O2 —> CO2 + H2O + Energy

Characteristics of Life

  • Biology is the study of life.

  • Characteristics of life:

    • Genetic code.

    • Grow.

    • Reproduce.

    • Metabolism.

    • Respond to stimuli.

    • Tend to change over time.

    • Made up of cells.

    • Movement.

    • Respire.

    • Consume nutrients.

    • Excrete waste.

  • Cell Theory

    1. Cells are the most basic unit of life.

    2. All living things are made up of cells.

    3. All cells come from pre-existing cells.

Biological Classification & Taxonomy

  • Taxonomy is a system to organize the vast number of species on Earth based on their evolutionary relationships and DNA similarities.

  • Taxonomists organize living and non-living organisms.

  • The largest grouping is known as a Domain (Bacteria, Archaea, Eukarya).

  • The Five Kingdom System:

    • Monera (Eubacteria, Archaebacteria).

    • Protista.

    • Plantae.

    • Fungi.

    • Animalia.

    • (Six Kingdom System splits bacteria into 2 Kingdoms).

  • A bit about the Kingdoms

    1. Bacteria (Eubacteria & Archaebacteria)

      • Unicellular, prokaryotic.

      • Believed to be the first organisms on Earth.

    2. Protista

      • Eukaryotic, mostly unicellular.

      • A broad group ranging from single-celled amoeba to slime molds and sea weeds.

    3. Plantae

      • Eukaryotic, autotrophic, multicellular.

      • Includes mosses, ferns, trees, and flowers.

    4. Animalia

      • Eukaryotic, heterotrophic, multicellular.

      • Organisms range from sea sponges to mammals.

    5. Fungi

      • Eukaryotic, heterotrophic, mostly multicellular (except yeast).

      • Organisms range from bread molds to mushrooms.

Taxonomic Groups

  • There are 8 subgroups (taxa) that classify organisms from the broad Domain into smaller and smaller groups until finally reaching individual species.

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

  • Classification of a Lion:

    • Domain: Eukarya.

    • Kingdom: Animalia.

    • Phylum: Chordata.

    • Class: Mammalia.

    • Order: Carnivora.

    • Family: Felidae.

    • Genus: Panthera.

    • Species: leo.

  • Going down the taxa:

    • Get more specific.

    • Groups get more related.

    • Fewer individuals.

  • Each species is given a name that can be easily recognized by biologists everywhere (Binomial Nomenclature),developed by Carlous Linneous:

    1. Genus name 1st Capitalized.

    2. Species name 2nd lowercase.

    3. Underlined (italics if typed).

    • Both words are generally in Latin.

    • Examples:

      • Homo sapiens (humans).

      • Canis lupus (wolf).

      • Bison bison (Bisons).

Types of Living Things

  • All living things can be grouped according to the type of building blocks from which they are made.

  • Most organisms are made up of one or more cells.

  • Viruses are non-cellular and have no cell machinery of their own; most biologists do not regard viruses as living organisms.

  • Cells can be divided into two basic sorts: prokaryotes and eukaryotes.

  • Eukaryotes can be further divided into plant, animal, protist, and fungal cell types.

  • The total collection of living organisms on Earth may be classified into 6 kingdoms: Animalia, Plantae, Protista, Fungi, Eubacteria, and Archaebacteria.

  • Viruses are not allocated a kingdom.

Cell Types and Kingdoms:

  • Plant Cells

    • Exist as part of a multicellular organism.

    • Possess a nucleus and membrane-bound organelles.

    • Autotrophic, adapted for photosynthesis; photosynthetic cells have chloroplasts.

    • Cell walls of cellulose.

    • Kingdom: Plantae.

    • Examples: xylem cell, phloem cell, mesophyll cell.

  • Animal Cells

    • Exist as part of a multicellular organism.

    • Possess a nucleus and membrane-bound organelles.

    • Heterotrophic.

    • Lack cell walls.

    • Responsive to stimuli.

    • Kingdom: Animalia.

    • Examples: Red blood cell (erythrocyte), neuron, muscle cell.

  • Protist Cells

    • Mainly single-celled or exist as cell colonies.

    • Possess a nucleus and membrane-bound organelles.

    • Some are autotrophic; some are heterotrophic.

    • Kingdom: Protista.

    • Examples: Paramecium, Euglena, Amoeba.

  • Fungal Cells

    • Rarely single cells.

    • Possess a nucleus and membrane-bound organelles.

    • Plant-like but lack chlorophyll.

    • Rigid cell walls that contain chitin.

    • Heterotrophic.

    • Kingdom: Fungi.

    • Examples: Hyphal cell, yeast cell, fungal spores.

  • Bacterial Cells

    • Single-celled.

    • Lack a distinct nucleus and membrane-bound organelles.

    • Cell walls of peptidoglycans.

    • Can cause illness in humans.

    • Kingdom: Bacteria.

    • Examples: Streptococcus, Salmonella, Staphylococcus.

  • Viruses

    • Non-cellular, covered in a protein coat.

    • Contain no cytoplasm or organelles; no chromosomes, just RNA or DNA strands.

    • Depend completely on cells for their metabolism and reproduction.

    • Kingdom: None.

    • Examples: HIV, Herpes simplex, Influenza.

Species Definition and Hybrids

  • Species: A group of similar organisms that can breed and produce fertile offspring under natural conditions.

  • Conditions to be considered a separate species:

    • Must breed.

    • Must produce offspring.

    • Offspring must be fertile.

    • Breeding must occur under natural conditions.

Hybrid Examples

  • Liger: Male lion + female tiger. NOT considered a species because they only breed in captivity.

  • Tigon (Tiglion or Tion): Male tiger + female lion. Also, NOT considered a species because they only breed in captivity.

  • Mule: Horse + donkey. Mules are NOT a separate species because they are sterile.

  • Beefalo: Bison + buffalo. Bred for meat, NOT a separate species because they were created artificially.

  • Cama: Cross between a camel and a llama.

  • Wolphin: Cross between a whale and a dolphin.

  • Zebroids: Hybrid.