General Biology I - Diversity of Life Quiz

General Biology I - 101-NYA-05

• Section: 00007/8
• Testing was conducted to see if animals "kiss"

Biology NYA Lecture 1 - Introduction to Biology

• Date: August 20th, 2024

Socrative

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• Room Name = GRIFFITHS2554
• Activity is not for marks, but for brain stimulation about Biology

Diversity of Life

• Approximately 2 million species have been identified to date; thousands more are identified annually.
• Estimates of total species range from 8-9 million.
• Taxonomy is the branch of biology that names and classifies species into groups based on increasing breadth.
• Domains, followed by kingdoms, are the broadest units of classification.

Three Domain Model

• Living things are categorized into three major groups (domains): Bacteria, Archaea, and Eukarya.
• Bacteria and Archaea are prokaryotes (lack a nucleus).
• Eukarya are eukaryotes (have a nucleus).

Domain Bacteria

• Most abundant organisms on Earth (more bacteria in your mouth than mammals on the planet).
• Found virtually everywhere.
• Some are helpful, some are harmful.
• Prokaryotic.
• Unicellular.
• Cell walls are composed of peptidoglycan.
• Most taxonomists recognize 12-15 different groups of bacteria.
• Helpful activities include decomposing organic material, degrading environmental pollutants, digesting cellulose in cows' stomachs. They can also produce vitamin K in human stomachs and make elements like nitrogen accessible to other organisms.
• Can cause diseases; attach to cells, causing tissue damage, and affect some plant diseases, and many human diseases, including syphilis, gonorrhea, chlamydia and typhoid fever.

Domain Archaea

• Prokaryotic.
• Unicellular.
• Not bacteria.
• Do not cause disease.
• Cell walls lack peptidoglycan.
• Grouped into three categories based on their environments or metabolic pathways: extremophiles, methanogens, and non-extreme archaea.
• Extremophiles thrive in extreme environments (e.g., high temperatures, high salt concentrations, extreme pH). Methanogens produce methane gas. Non-extreme archaea live in environments similar to bacteria.

Domain Eukarya

• Very diverse.
• Three characteristics distinguish them from prokaryotes: compartmentalization, membrane-bound nucleus, and differences in gene expression.
• Compartmentalization involves discrete compartments within cells.
• Eukaryotic DNA is stored within a membrane-bound nucleus.
• Eukaryotes exhibit diverse gene expression.
• Eukarya deal with environments via specialized approaches.
• Eukarya's major characteristic is sexual reproduction, which leads to genetic diversity.

Kingdom Protista

• Diverse group of eukaryotes, mostly inhabiting moist or aquatic environments.

• Primarily unicellular, with some that are colonial or multicellular.

• First eukaryotes that evolved approximately 2.1 billion years ago.

• Protista classification is in flux (some believe it should have more kingdoms).

• Types of protists include:

  • Animal-like protists: Phagotrophs, use pseudopods for movement, engulf food in vacuoles, digest food with enzymes
  • Plant-like protists: Phototrophs, are autotrophs
  • Fungus-like protists

Kingdom Plantae

• Multicellular eukaryotic organisms, considered autotrophs that produce their food through photosynthesis.
• Produce their own food and essential chemicals from simple substances present in the environment.
• Self-sufficient (possess their own cellular walls).
• Examples include: trees, flowers, and ferns.

Kingdom Fungi

• Includes molds and mushrooms.
• Heterotrophic; obtain energy and essential chemicals from preformed organic matter.
• Decomposers (break down dead organic matter), or in some cases are parasites (derive nutrients from living hosts.)
• Some fungi are also mutualistic (beneficial to both partners).

Kingdom Animalia

• Consists of all animals.
• Multicellular eukaryotes.
• Diverse group with varying similarities among species.
• Heterotrophic; need to obtain energy and organic building blocks from the intake and digestion of other organisms (plants or other animals).

Classification of Organisms

• Taxonomy is the science of classifying living organisms.
• A classification level is called a taxon.
• Scientific names avoid the confusion of common names.
• Organisms are classified based on shared characteristics (e.g., a dichotomous key, which employs simple yes-or-no questions).

The Binomial System

• Each organism has a unique binomial name (two-word name).
• The system uses Latin names, with the first word capitalized and the second in lowercase.
• Both words are italicized, and the first word is the genus name, while the second is the species' name.

The Linnaean Hierarchy

• An organizational scheme, where organisms are arranged into progressively larger inclusive categories, following the order of Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Dichotomous Key

• A tool used to identify organisms based on a series of observable characteristics and questions.
• Questions present two mutually exclusive options for each stage leading to the identification of organisms.