Diversity of Living Things

Biodiversity

The number and variety of species and ecosystems on Earth

Species

All organisms capable of breeding freely with each other under natural conditions

Hybridization

The crossbreeding of two different species

Morphology

The physical appearance and characteristics of an organism; also the science of the study of these physical characteristics

Evolutionary changes

A change that occurs in an entire population; usually occurs over a long period of time

Genetic diversity

The genetic variability among organisms -- usually referring to individuals of the same species

Species diversity

A measure of diversity that takes into account the quantity of each species present, as well as the variety of different species present

Structural diversity

The range of physical shapes and sizes within a habitat or ecosystem

Species interaction

Food supply, protection, transportation, reproduction, hygiene, and digestion

Biological classification

The systematic grouping of organisms into biological categories based on physical and evolutionary relationships

Taxonomy

The science of classifying all organisms; taxonomists classify both living and fossil species

Carl Linnaeus

A Swedish naturalist (1707-1778) who is considered to be the "father" of taxonomy; he introduced a consistent way of grouping species according to morphological similarities and established a naming system

Genus

A taxonomic level consisting of a similar group of similar species

Binomial nomenclature

The formal system of naming species whereby each species is assigned a genus name followed by a specific name

Seven taxa

Kingdom, phylum, class, order, family, genus, species

Dichotomous key

Phylogeny

The study of the evolutionary relatedness between, and among, species

Phylogenetic tree

A diagram depicting the evolutionary relationships between different species or groups

Clade

A taxonomic group that includes a single common ancestor and all its descendants

Prokaryote

A single-celled organism that does not contain membrane bound organelles

Eukaryote

Any organism whose cells contain organelles; some eukaryotic organisms are single-celled, while others are multicellular

Six Kingdoms of Life

Eubacteria, archaea, protista, fungi, plants, and animals

Eubacteria

-Prokaryotic

-Cell walls contain a unique compound

-Cells are variable in shape and size

-Have diverse means of obtaining energy/nutrients

-All can reproduce asexually

Archaea

-Prokaryotic

-Cells walls and cell membranes have a unique structure

-Most are extremely small

-Some colonize extreme environments

-All can reproduce asexually

Protista

-Eukaryotic

-Cells have extreme diversity of cellular structure

-Some have chloroplasts and cell walls

-May be heterotrophic/autotrophic/both

-Have variable forms of movement

-Usually live in aquatic or other moist environments

-Reproduce asexually and sexually

Fungi

-Eukaryotic

-Cell wall composed of chitin

-Most are multicellular

-Cells have no chloroplasts

-All are heterotrophic

-Most are terrestrial

-Reproduce asexually and sexually

Plants

-Eukaryotic

-All are multicellular

-Cell walls are composed of cellulose

-Possess chloroplasts

-Are autotrophic and photosynthetic

-Most are terrestrial

-Reproduce asexually and sexually

Animals

-Eukaryotic

-All are multicellular

-Cells have no walls or chloroplasts

-All are heterotrophic

-Most reproduce sexually

-Live in terrestrial and aquatic environments

Three Domains of Life

Eubacteria, Archaea, Eukaryotes

Six Major Groups of Bacteria

Proteobacteria (purple bacteria), green bacteria, cyanobacteria (blue-green algae), gram-positive bacteria, spirochetes, chlamydias

Proteobacteria (purple bacteria)

-Some are photosynthetic with a form of photosynthesis different from plants

-Ancient forms of these bacteria were the likely ancestors of eukaryotic mitochondria

-Some are nitrogen fixing

-Are responsible for many diseases including bubonic plague, gonorrhea, dysentery, and some ulcers

Green bacteria

-Use a form of photosynthesis that differs from plants

-Are usually found in salt water environments or hot springs

Cyanobacteria (blue-green bacteria)

-Use a form of photosynthesis similar to plants and other eukaryotes

-Ancient forms of these bacteria were likely the ancestors of eukaryotic chloroplasts

-Play major roles as produces and nitrogen fixers in aquatic ecosystems

-Form symbiotic relationships with fungi

Gram-positive bacteria

-They cause many disorders (anthrax, strep throat, bacterial pneumonia, and meningitis)

-Used in food production

-Some lost their cell wall

-One type -- mycoplasms -- are smallest known cells

Spriochetes

-Spiral-shaped flagellum is embedded in their cytoplasm

-Move with corkscrew motion

-Cause syphilis

Chlamydias

-All are parasite that live within other cells

-Cause chlamydia, one of the most common STIs

-Cause trachoma, leading cause of blindness in humans

Plasmid

A small loop of DNA often found in prokaryotic cells; usually contains a small number of genes

Capsule

An outer layer on some bacteria; provides some protection for the cell

Coccus

Round bacterial cell

Bacillus

Rod-shaped bacterial cell

Spirillum

Spiral or corkscrew-shaped bacterial cell

Diplo

Pairs

Staphylo

Clumps

Strepto

Strings

Obligate aerobe

A organism that cannot survive without oxygen

Facultative aerobe

An organism that can live with or without oxygen

Fermentation

An anaerobic process that releases chemical energy from food

Obligate anaerobe

An organism that cannot survive in the presence of oxygen

Binary fission

The division of one parent cell into two genetically identical daughter cells; a form of asexual reproduction

Conjugation

A form of sexual reproduction in which two cells join to exchange genetic information

Transformation

A process in which a bacterial cell takes in and uses pieces of DNA from its environment

Horizontal gene transfer

Any process in which one species gets DNA from a different species

Endospore

A dormant structure that forms inside certain bacteria in response stress; protects the cell's chromosome from damage

Importance of bacteria

-Play key roles in ecosystems, many are decomposers and producers

-Recycle nutrients and are vital to biogeochemical cycles

-Fix, or convert, atmospheric nitrogen into chemical compounds

-Essential residents in the intestines of animals

-Essential in production of foods

-Produce antibiotics

Meningococcal disease

Caused by bacterium Neisseria meningitidis

Carried by humans in the nose and throat and are spread into the air by coughing and/or sneezing.

Can resemble symptoms of other diseases, such as flu. They include fever, headache, stiff neck, irritability, and nausea and vomiting. Can develop rapidly and dramatically, within minutes to hours. Fever can be very high and the headache can be intense.

A vaccine to prevent meningococcal disease is available for children and certain persons at risk for the disease

Treatment includes hospitalization, generally ICU, and immediate administration of IV antibiotics. Complications, such as brain swelling, seizures, and coma will also need aggressive intensive care treatment.

Antibiotic resistance

Groups of Archaea

Methanogens, halophiles, extreme thermophiles, psychrophiles

Methanogens

-Live in low oxygen environments (swamps, lakes, marshes, sewage lagoons, digestive tracts and insects)

-They generate energy by converting chemical compounds into methane

Halophiles

-They are salt-loving organisms that can live in highly saline environments

-Most are aerobic and get energy from organic food molecules

-Some use light as a secondary energy source

Extreme thermophiles

-They live in extremely hot environments (hot springs, hydrothermal vents)

-Optimal temperature range for growth is 70-90 degrees C

Psychrophiles

-They are cold-loving organisms fond mostly in the Antarctic and Arctic oceans

-Optimal temperature range for growth is -10 - -20 degrees C

Virus

A small infectious particle containing genetic material in the form of DNA or RNA within a protein capsule

Capsid

A protein coat that surrounds the DNA or RNA of a virus

RNA (ribonucleic acid)

A nucleic acid found in all cells and some viruses; usually carries genetic information that provides instructions for synthesizing protein

Bacteriophages

A virus that infects bacteria

Lytic cycle

Lysogenic cycle

Lysis

The rupturing of a cell; can occur when newly made viruses are released from a host cell

Lysogeny

A state of dormancy in which viral DNA may remain within a host cell's chromosome for many cell cycle generations

Transduction

A type of gene transfer in which a virus transfers DNA from one bacterium to another

Vaccines

Mixtures that contain weakened forms or parts of a dangerous virus

Gene therapy

A method of treating disease in which genes are introduced into cells to replace, supplement, or repair a defective gene

Viroid

Very small infectious piece of RNA for some serious diseases in plants (smaller than viruses and do not have capsids)

Prion

Abnormally shaped infectious protein responsible for some brain diseases of mammals, including humans

Endosymbiosis

Relationship in which a single-celled organism lives within the cell(s) of another organism

Origins of Eukaryotes

Protists were the first. Membrane of ancestral prokaryotic cell folded developing internal membranes bounding organelles. Later endosymbiosis occured

Seven Groups of Protists

Euglenoids, ciliates, apicomplexa, diatoms, amoebas, slime moulds, red algae

Euglenoids

-Autotrophs, photosynthetic

-Unicellular

-Usually have two flagella

-Outer surface covering consists of stiff proteins

Ciliates

-Heterotrophs

-Unicellular

-Have very complex internal structures

-Have many cilia and no cell walls

Apicomplexa

-Heterotrophs

-Unicellular

-No cell wall

-All are parasites of animals

Diatoms

-Autotrophs, photosynthetic

-Unicellular

-Move by gliding

-Covered by glass like silica shells

Amoebas

-Heterotrophs

-Some have hard outer skeletons

-Move by extensions of the cytoplasm called pseudopods

Slime moulds

-Heterotrophs

-Life cycles have unicellular and multicellular stages

-Move with flagella or pseudopods

Red algae

-Autotrophs, photosynthetic

-Almost all are multicellular

-Have no cilia or flagella

-Cell walls are made of cellulose

Haploid

A cell containing half the usual complement of chromosomes (n)

Diploid

A cell containing two copies of each chromosome (2n)

Zygote

A cell formed by the fusion of two sex cells; is diploid

Life cycle of brown algae

Zygote (diploid)

Young sporophyte

Mature sporophyte

Haploid spores released

Male gametophyte and female gametophytes release gametes

Sperm fertilizes egg

Sporophyte

A diploid organism that produces haploid spores in an alteration of generations life cycle

Spore

A haploid reproductive structure; usually a single cell; capable of growing into a new individual

Gametophyte

A haploid organism that produces haploid sex cells in an alteration of generations life cycle

Alteration of generations

A life cycle in which diploid individuals produce spores that create haploid individuals; the haploid individuals produce sexually, producing sporophyte individuals and completing the cycle

Why Fungi Are Important

-Along with bacteria, major decomposers of the Earth

-Responsible for much of the cycling of nutrients

-Engage in important symbiotic relationships

-Serve as food and alcohol

Five Major Phyla of Fungi

Chytrids, zygomycetes, glomeromycetes, ascomycetes, basidiomycetes

Chytrids

-Only phylum with swimming spores

-Most are saprophytes

-Can be unicellular or multicellular

Zygomycetes

-Include some familiar bread and fruit moulds

-Most are in soil environments

-Many used commercially

-Many parasites of insects

Glomeromycetes

-All form symbiotic relationships with plant roots

Ascomycetes

-Many, such as yeast, useful to humans

-Some cause serious plant diseases (like cordyceps)

Basidiomycetes

-Include mushrooms, puffballs, and bracket

-Most are decomposers

-Some form symbiotic relationships with plants

Mycelium

A branched mass of hyphae (that make up the bodies of most fungi)