Glossary of Terms for this Unit Section
- Animals (Kingdom Animalia): Are eukaryotic and multicellular, which makes them different from bacteria and most protists. Cells have no cell wall which distinguishes them from plants, algae, and fungi. Have layers of tissues (muscles, nerves, etc..), specialized organs, and their body plan eventually becomes fixed as they develop with a well-defined shape and size, though some undergo a process of metamorphosis later in life. Are consumers, eating other plants and animals for energy. They generally digest food in an internal chamber that has one or two openings, which makes them different from plants and algae. Show mobility at some stage during their lives, allowing them to move spontaneously and independently. Nearly all undergo some form of sexual reproduction. They have specialized reproductive cells. Many animals are also capable of asexual reproduction.
- Archaea (Domain Archaea): One of the three domains. These are single-celled prokaryotic microorganisms. They have no cell nucleus or any other membrane-bound organelles within their cells. Originally they were classified with bacteria as prokaryotes due to their visual similarities in size and shape. However, they have been given their own domain apart from Bacteria, because it has been seen that Archaea have an independent evolutionary history and have many differences in their biochemistry than other forms of life.
- Aristotle: Developed the Great Chain of Being with Plato. Responsible for dividing the living world between plants and animals and classifying over 500 organisms.
- Bacteria (Domain Bacteria): Prokaryotic organsism that do not have a nucleus and rarely contain membrane-bound organelles. Have a wide variety of sizes and shapes. A bacterial cell is surrounded by a cell membrane, and most have a cell wall which is vital to their survival. Generally there is considered to be two main types that are distinguished by cell wall structure: gram-positive and gram-negative. Is one of the three domains.
- Binomial Naming: The Scientific Naming system where each species is assigned a genus name followed by a species name, where both words are italicized. The two words together form the species’ name: Genus species
- Biodiversity: The number and variety of species and ecosystems on Earth.
- Carl Linnaeus: The “father” of taxonomy. He grouped organisms into taxons (Kingdom, Phylum, Class, Order, Family, Genus, Species) and devised a consistent way of grouping species according to their morphological similarities.
- Carl Woese: Developed the Three Domains of Life system, with domains being a higher taxon than kingdoms.
- Classification: A way to group organisms together in a meaningful way.
- Dichotomous Key: a method used in taxonomy to categorize species. It is a form of a single access key where there are only two choices at each branching point. By answering the questions, the key leads to the smallest available classification unit, which is usually a species or a specific taxon.
- Domain: The highest taxonomic level of the modern system of classification according to Woese. It is also the broadest range of classification for life and also the largest. There are three domains: Bacteria, Eukarya, Archaea
- Eukarya (Domain Eukarya): One of the three domains. Refers to organisms cells contain complex structures contained within membranes. The defining feature of this group is the presence of the nucleus, within which genetic material is contained. Most eukaryotic cells also contain other membrane-bound organelles such as mitochondria, chloroplasts, and golgi apparatus.
- Eukaryote: Eukaryotes are organisms whose cells contain complex structures enclosed within membranes. Most importantly as a distinguishing factor between eukaryotes and prokaryotes is the presence of a nucleus, within which the genetic material is located. Most eukaryotes can also contain other membrane-bound organelles such as: mitochondira, chloroplasts, and golgi apparatus. All eukaryotes are within the taxon Eukarya. Most are complex organisms such as animals, plants, and fungi. However, this group also contains many unicellular organisms.
- Fungi (Kingdom Fungi): Cells have cell walls that contain chitin, unlike plants which contain cellulose. Are more similar to animals than to plants. Fungi excrete enzymes into the environment into order to absorb food. They cannot make their own food. Through this they perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange.
- Genetic Diversity: Variety of heritable characteristics in a healthy breeding population.
- Great Chain of Being: A religious hierarchical structure for all matter and life and was believed to be decreed by God. In this system, the chain began with God, followed by angelic beings, humanity, animals, plants, and then minerals. Each level of the chain could be further subdivided.
- Group: A group of similar species.
- Invertebrates: Are animal species that do not develop a vertebral column. This includes all animals apart from the subphylum Vertebrata. Most animal species are invertebrates, since only about 3% of animal species include a vertebral column in their anatomy.
- Kingdom: The highest taxonomic level of the traditional Linneaen system of classification.There are six Kingdoms under the Woese System: Bacteria, Archaea, Protista, Animalia, Plantae, Fungi
- Morphological traits: The physical traits of an organism.
- Mycology: The branch of biology concerned with the systematic study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source of medicine, food, psychotropic substances, as well as their dangers through poisoning or infection.
- Plants (Kingdom Plantae): Plants are immobile multi-cellular organisms that contain cell walls with cellulose that can be found on land or in water. They can be classified by their sexual reproduction, modular and indeterminate growth, and an alternation of generations. Asexual reproduction is common, and some plants only bloom once, while others only bear one bloom. Are producers obtaining most of their energy from the sun via photosynthesis using chlorophyll contained in chloroplasts which give them their green colour.
- Prokaryote: A group of organisms whose cells lack a cell nucleus and do not have any membrane-bound organelles. All of the intra-cellular water-soluble are located together in the same area enclosed by a membrane.
- Protists (Kingdom Protista): The most ancient of the eukaryotic life forms and a very diverse group of microorganisms. They include a variety of single-celled organisms and those that form colonial multi-cellular organism that do not show differentiation into tissues. Beside their relatively simple levels of organization, protists do not have much in common. It is this simple cellular organization that is what distinguishes the protists from other eukaryotes such as fungi, animals, and plants. Thus they can perhaps be best described as eukaryotes that are not fungi, animals, or plants.
- Species: A group of organisms that share similar structures and interbreed together under natural conditions.
- Species Diversity: Variety and abundance of species in a given area.
- Taxa (singular): A group in the classification system. The taxon (plural) order are: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Speices.
- Taxonomists: Scientists that do taxonomy.
- Taxonomy: The science of identifying and classifying all organisms.
- Vertebrates: Are animals that are members of the subphylum vertebrata. They make up most of the phylum Chordata. All vertebrates follow the basic chordate body plan which includes a stiff rod running though the length of the animal, a vertebral colum or notochord. They also have a hollow tube of nervous tissue, the spinal cord, above it, and the gastrointestinal tract below it. The mouth is found at or right below the anterior end of the animal with the anus opening to the exterior before the end of the body.