Unit 9 was about what on earth evolved. The very first concept we learned was about classification and evolutionary relationships. Taxonomy is the study of naming and classifying organisms, with the purpose to avoid confusion with common names. Carolus Linnaeus a Swedish botanist who live in the early 1700s originally classified all life as plant or animal and create the 7 levels of organization including the scientific name, known as the binomial nomenclature. The binomial nomenclature is a two name system to name organisms made up of the genus and species names. There are certain rules to the name process; If you discover the ograms, you name it. It must the underlined or italicizes, the genus name is capitalized and the species name is lowercased. It is based on Latin. Phylogeny is the evolutionary history and relationships of species using taxonomy The phylogenetic tree shows shared ancestry. Node,s where th branches meet, present a common ancestor. There are 7 main taxonomic levels: Kingdom, Phylum, Class, Order, Family, Genus, and Species.
The second concept we learned about was Kingdoms and Domains. Taxonomic groups go from broad to narrow are domain, kingdom, phylum, class, order, family, genus and species. There are three main domains, Archaea, Bacteria, and Eukarya. In the Eukarya domain, there are 4 main kingdoms - protista, fungi, plantae, and animalia. It is really fascinating to see that we are only 1 of the 800,000 species in the Animalia kingdom, and there are 799,999 other consumers and heterotrophs that are in the same kingdom The Archaea domain live near hydrothermal vents, hot springs, digestive tracts of animals, anoxic muds and marshes and petroleum deposits. . The protista are very diverse, while fungi are decomposers and heterotrophic, while plantae come in both vascular and nonvascular forms
Next, we learned about Bacteria and Viruses. Earth’s first organisms were likely prokaryotes, and most prokaryotes are unicellular. There are three common shapes of of bacteria, spheres (cocci), rods (bacilli) and spirals. Bacterial cell walls contain peptidoglycan, a network of sugar polymers cross linked by polypeptides. Scientists use the gram stain to classify bacteria by cell wall composition. Gram positive bacteria have simpler walls with large amount of peptidoglycan, and gram negative bacteria have less peptidoglycan and an outer membrane that can be toxic. Most mobile bacteria propel themselves by flagella scattered about the surface of concentrates at one of both engs. Chemoheterotrophs: Heterotrophic bacteria that take in organic molecules. Ex: Staphylococcus aureus in undercooked food Photoautotrophs: Use light to convert carbon dioxide and water into carbon compounds. Ex: cyanobacteria Chemoautotrophs: Use energy directly from chemical reactions involving ammonia, hydrogen sulfide, nitrites, sulfur, or iron. Obligate aerobe: Must have oxygen to survive. Ex: Tuberculosis - Mycobacterium tuberculosis Obligate anaerobes: Can not have oxygen. Botulism from canned food. Ex: Clostridium botulinum Facultative anaerobes: Alternate between oxygen and fermentation depending on change in environment.
We also learned about viruses in the same lesson. Viruses are not cells, it is a very small infectious particle consisting of nucleic acid enclosed in a protein coat and in some cases, a membranous envelope. Viral genomes may consist of either double or single stranded DNa or double or single stranded RNA. A capsized is the protein shell that encloses the viral genome. Some viruses have membranous envelopes that help them infect hosts called viral envelopes. They are derived from the host cell’s membrane and they contain a combination of viral and host cell molecules. Once a viral genome has entered a cell, the cell begins to manufacture viral proteins. The virus makes use of host enzymes, ribosomes, tRNAs, amino acids, ATP, and molecules. Viral nucleic acid molecules and capsomeres spontaneously self-assemble into new viruses. Lytic Infection: Virus enters a cell, makes copies of itself, and causes the cell to burst. Lysogenic Infection: A virus integrates its DNA into the DNA of the host cell, and the viral genetic information replicates along with the host cell’s DNA.
Next, we learned about fungi and plants. Plants and fungi have different traits. Fungal walls are made of chitin, while plants cell walls are made of cellulose. PLants have chlorophyll and photosynthesis while fungi absorb food through hyphae. There are three main types of fungi - sac fungi, bread molds and club fungi. Fungi Can also act as mutualists - lichens form between fungi and algae while mycorrhizae form between fungi and plants. They are useful in several ways, as food, antibiotics, and as model system for molecular biology. They can also cat as pathogens, preventing human diseases including ringworm and athlete's foot, and plant diseases including Dutch elm disease. Plants, first grew at the edges of water, and evolved through natural selection. Bryophytes are the mosses, and their relatives are the seedless nonvascular plants. Pterophyta are ferns and they are seedless vascular plants. Their vascular system allows them to get off the ground resulting in more photosynthesis. Roots allow absorption of water and nutrients, while the leaves allow for more photosynthesis. Gymnosperms are cone bearing plants which their seeds in cones. The cone is the reproductive structure of most gymnosperms. There are three major phyla - Cycads, Ginkgos and Conifers. Angiosperms are flowering plants with seeds enclosed in the fruits. It is one phylum and it is the largest in the plant kingdom. There are two major types of angiosperms, monocots and dicots.
After plants, we learned about invertebrates which make up 97 percent of all animal species. Difference in their body plants result from different in expression of Hox genes, which tell embryonic cells which body part or\to become. Animals are grouped using a variety of criteria -body plan symmetry, tissue layers and developmental patterns. Major Invertebrate phyla include sponges, phylum Porifera, cnidarians, flatworms, and mollusks. Sponges are the most primitive species of Earth and share common characteristics - they are sessile ad have no symmetry. They reproduc eboth sexuall and asecxually and their cells work together to filter feed. Flatworms have a solid body and an incomplete or absent gut, many are parasitic. Mollusks are bilateral animals and have a complete digestive tract. Annelids have segmented bodies and a coelom. Arthropods are the most diverse of all animals and their features are highly adapted. They have an exoskeleton made of chitin, jointed appendages and segmented body parts. Arthropods also have an open circulatory system. Insects are the dominant terrestrial arthropod, they have three pairs of legs and one pair of antennae. Their body has three parts - the head thorax and abdomen. Crustaceans are a diverse group of ancient arthropods, and they share several common features. They have two distinct body sections and one pair of appendages per segment. Echinoderms are on the same evolutionary branch as vertebrates - they have radial symmetry, they have an internal skeleton and a water vascular system.
Chordates are all vertebrates and some invertebrates. An endoskeleton allows vertebrates to grow to large sizes. There are seven main classes of vertebrate chordates. Agnatha, jawless fish, chondrichthyes, cartilaginous fish with jaws, osteichthyes, bony fish with haws, amphibia, four limbed animals that can live on water and land, reptiles, lay eggs surrounded by membranes, aves, birds, and mammals, hairy animals. There are only two classes of Agnatha that still exist, lampreys and hagfish. Amphibians evolved from lobe finned fish and a number of adaptation allow them to live on land. They have large shoulders, mobile and muscular tongues, and they breathe through skin or with gills. The amniotic egg allowed vertebrates to reproduce on land. Reptiles are a diverse group of amniotes that share several characteristics - ectothermal, covered with scales, three chambered heart, and cloaca. Birds evolved from theropod dinosaurs and they share several anatomical features - hollow bones, fused collarbones and rearranged hip muscles. Mammals are the dominant terrestrial arthropod.
There are a few unanswered questions that I have. Of the many phylums, which do scientists study the most and what organisms have the best medicinal uses. I really enjoyed learning about invertebrates and I would love to learn more about them
This is my presentation for what on earth evolved. I loved the presentation as I was able to learn more about the organism and practice speaking about a topic. I could have practiced a bit more and even changed my slides to include less information so I could have talked more about the species rather than reading off the slides. I hope to do more presentations like this one in the future especially in science topics as it really helped me.
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