Diversity

Characteristics of Living Things

  • Growth - all living things grow from the inside out, not like a snowball which grows from the outside

  • Reproduction - Limited life span and need to reproduce to replace themselves

  • Adaptation - adapt to the environment in ways favourable to them; ie) thicker fure, blink, turn on lights, etc.

  • Metabolism - use food to provide energy and carry out bodily functions

  • Movement - Migration

  • Irritability - response to stimulus; heat, noise, light

  • Cells - w proteins, carbs, lipids, water, and genetic mats; only living things have this combination

  • Waste

Classify - Assign “things” into specific categories

Why? To org our understanding, make

Species - a group of org that can interbreed in nature and produce fertile offspring

  • There are 30-100 mill diff species in the world. Scientists have struggled to agree on a consistent “species” definition. There are three commonly used species concepts:

Species Concepts

Morphological

  • focuses on morphology (shape size descriptions, etc.)

  • Advantage: simple

  • Disadvantage: trying to decide how much difference between two organisms is enough to separate them

Biological

  • Focuses on the organism's ability to interbreed and produce fertile offspring in nature

  • Advantage: widely used

  • Disadvantage: Can’t be applied in all situations

phylogenetic

  • Focuses on the evolutionary relationships between organisms

  • Advantage: can be applied to extinct species

  • Disadvantage: Phylogeny of all species isn’t known

Linnaean System of Classification

Carl Linnaeus - Father of Taxonomy

Taxonomy - classifying, identifying and naming species based on morphology

Taxon: a named group of organisms such as phylum Chordata or order Rodentia

Rank: a lvl in a classification scheme, such as phylum or order

Binomial Nomenclature

  • fancy way of saying: “Using two words in a name”

  • Used to give a species their sci name

    • Genus: Homo

      • written before species

      • always capitalized,

      • always italicized

      • sometimes abbreviated

    • Species: sapiens

      • Written after genus

      • always lower case

      • always italicized

  • Homosapiens

Think: General () Specific Genus () Species

note: when handwriting genus and species names, underline both

Taxonomic classification

  • Genus and species are two of over 8 taxonomic ranks

  • Organized from most general to most specific

specific to less specific

Species —> Genus —> Family —> Order —> Class —> Phylum —> Kingdom —> Domain

dumb king Philip came over for grape soda

What are the 3 Domains

  • Eukaryota/Eukarya

  • Bacteria

  • Achaea

What are the 6 Kingdoms

  • Archaebacteria

    • Extremophiles

      • live in extreme environments; prokaryotes; very old

  • Eubacteria

    • “true bacteria”, prokaryotes

  • Protista

    • single-celled eukaryotes; mobile

  • Fungi

    • multi-cellular; mushrooms, yeasts, moulds; respire through absorption

  • Plantae

    • Plants; multicellular

  • Animalia

    • Animals; multicellular

Ancestor: an organism (or organisms) from which other groups of organisms are descended

Anatomy: study of the structure of organisms

Physiology: The study of the functioning of organisms (physical, chemical funct and internal processes)

Phylogenetic tree: a branching diagram used to show the evolutionary relationships among species

Structural Diversity:

(Cladograms might be a test question)

Domains, prokaryotes vs eukaryones

Discovery Order of Kingdoms: animals and plants, then protists, then bacteria, then fungi, then Archaea

Prokaryotic: A smaller, simple type of cell that does not have a membrane-bound nucleus

Prokaryotic: a smaller, simple type of cell that does not have membrane-bound nucleus

Prokaryotic kingdoms": Archaea, Bacteria (also domains)

Eukaryotic Kingdoms: Prostista, Fungi, Plantae, Animalia

Dichotomous key: an identification tool consisting of a series of two-part choices that lead the user to a correct identification (super easy)

Autotroph: an organism that captures energy from sunlight (or sometimes non-living substances) to produce its own energy-yielding food

Heterotroph: an organism that cannot make its own food and gets its nutrients and energy from consuming other organisms

Bacteria: Staphylococcus, prokaryotic, unicellular, peptidoglycan, autotrophs and heterotrophs

Archaea: Sulfolobus Archea, unicellular, not peptidoglycan; occasionally no cell wall

Protista: Amoeba, Eukaryote, Unicellular and multi-cellular, cellulose in some occasionally no cell wall, Autotrophs and heterotrophs, A sexual and sexual

Plantae: maple tree, Eukaryote, multicellular, cellulose, autotrophs, sexual

Fungi: Mushroom, Eukaryote, Mostly multicellular, Chitin, heterotrophs, sexual

Animalia: Rabbit, Eukaryote, Multicellular, no cell wall, Heterotrophs, sexual

Prokaryotes do not have membrane-bound nucleus

Viruses

Viruses do not fulfill all the criteria in life, but they do meet some of the criteria

Evidence that viruses are not-living:

  • Do not grow or carry out respiration

  • Only contain one kind of nucleic acid; RNA or DNA

  • Contain only a few enzymes

Evidence that viruses are living:

  • Contain one nucleic acid

  • They can replicate (But require a living cell)

  • They can evolve

Viral nomenclature

They are named for the disease they cause, ex, rabies virus, polio virus

or for the tissue they infect, ex, adenovirus (attacks adenoid tissue)

Viral Characteristics

  1. Core

  • Nucliec Acid

    • Set of genetic instructions

    • Either DNA or RNA

    • single stranded or double stranded

  1. Capsid

  • Protien Coat

    • Surrounds nucleic acid to protect it

  • Lipid Membrane

    *Only in some viruses

    - if present - “enveloped virus”

    - If absent - “naked virus”

    - surrounds protein coat

Shape

  • Determined by the proteins in their coats

  • Play a role in the infection process

  • Examples: Helical, Spherical and Icosahedral (20 sided)

Virus structure

Bacteriophage

  • A virus that infects bacteria

  • Distinct head and tail region

Viral Reproduction

  • Viruses do not carry the chemical machinery needed to carry out the chemical reactions of life

  • They only carry one or two enzymes required to de-code their genetic material

  • A virus must have a HOST CELL in which to live and make more viruses

Host Cell

  • Can be animal, plant, or bacteria

  • Viruses are selective host specific

  • Host range - number of host species, tissue or cells a virus can infect

  • Broad host range

    • Rabies - infect humans, dogs, raccoons

  • Narrow Host Range

    • Cold Virus - infect upper respiratory tract in humans

Viral infection: Lytic Cycle

  • Attachment and Entrance

    • A virus particle attaches to a host cell

    • Viral Specificity - Viral protein coat must match receptor site on host cell

    • Particle releases its genetic instructions into host cell

  • Synthesis

    • The injected genetic material recruits the host cell’s enzymes to replicate its viral components

  • Assembly

    • Viral components (nucleic acid, enzymes, proteins) are assembled into new virus particles

Release

  • New virus particles are released from the host cell

2 Methods of release:

  • Lysis: virus particles break the host cell open and destroy it

  • Budding: virus particles pinch out from the host cell membrane (enveloped viruses)

Viral infection: Lysogenic Cycle

  • Some viruses do not reproduce right away, called: retrovirus

  • It co-exists with host cell integrating its own nucleic acid with the host cell’s DNA

  • The virus contains an enzyme (reverse transcriptase) that copies the viral RNA into DNA

  • When the host cell reproduces, the viral genetic instructions get copied into the host cell’s offspring

  • The virus remains “dormant” until triggered - then it takes over the host cell via the Lytic Cycle

  • ex, HIV

Lytic Cycle - virus replicates and bursts from cell

Lysogenic Cycle - viral nucleic DNA merges with host cell DNA and is replicated through host cell’s reproduction

Viruses and human health

  • Destruction of host cells causes symptoms of the disease

  • Viruses are NOT destroyed by antibiotics

  • Vaccines of inactive forms of viruses that are injected so that the body can produce antibodies. These antibodies allow for the body to become immune to the disease

Immunization

  • Active immunity: is when the body manufactures antibodies to combat a disease

  • The lymph nodes store the memory of the antibody so that it can be produced again if needed

  • The immunity is life-long and was under natural circumstances

Passive immunity

  • Passive immunity: temporary antibodies transferred to a person from another person or animal

  • Antibodies are transferred from a mother to her fetus through the placenta so that the fetus will be immune to the same viruses as the mother for a short time. This is why babies need vaccinations when they are a few months old

  • Ex: A tetanus shot contains antibodies from a horse exposed to the tetanus toxin. Thus, antibody production can be stimulated. Tetanus shots are taken every 10 years.