Classifying Life's Diversity PDF

Classifying Life’s Diversity Species - group of organisms that interbreed, producing fertile and viable offspring Interbreeding = two organisms of the same kind mate to make babies (aka. offspring) Fertile: offspring that can also breed babies Viable: being able to live and grow proper...

Classifying Life’s Diversity Species - group of organisms that interbreed, producing fertile and viable offspring Interbreeding = two organisms of the same kind mate to make babies (aka. offspring) Fertile: offspring that can also breed babies Viable: being able to live and grow properly Morphological Biological Phylogenetic structure/form fertile offspring evolutionary history compares identifies similar Evolutionary relations to measurements of similar characteristics for the living things living things same species ✔ useful for analyzing ✔ simple, commonly ✔ well-understood, DNA of species used, especially for used often ✔ can be used for plants extinct species 𝙓 hard to decide how 𝙓 can’t apply to 𝙓 evolutionary history is much physical variation specific species pretty unknown is “too much” (physically separated, asexual, fossils) Binomial Nomenclature - scientific two-name system; genus and species → to help specify organisms Name is based off of the characteristics 1. Genus: group of organism that it belongs to 2. Species: group of organisms Binomial = something with two parts Nomenclature = Naming system Homo sapiens GENUS name (CAPITALIZED) species name (lower case) Scientific name should be underlined separately GENUS → always capitalized species → always lowercase Hierarchical Classification Hierarchy of groups Each group is a taxon Divided within subgroups based on similar traits Taxonomic Categories (Ranks) Species = smallest most specific taxon Domain = largest most general group If the group is large, subgroups can be added to it Taxonomy tells CLASSIFIES and NAMES species Linnaeus developed BINOMIAL NOMENCLATURE system to name species; more common features = more closely related Morphology: structure and form of organisms (body, size)  Anatomy: structure of organisms (and internal structures) Physiology: how functioning organisms work Proteins are determined by genes, similarities can be seen in relation to other organisms Phylogenetic tree: shows how species are related through evolution ○ Roots: Represent the oldest common ancestor. ○ Branches: End at present-day species. ○ Forks: Points where a species split or evolved. Primitive Characteristics: Traits shared by all species from a common ancestor Derived Characteristics: New traits that appear as species evolve Time Scale: Closely related species (e.g., same genus) split more recently than more distantly related species (e.g., different families) Importance of Classification in Medicine: Related species may produce similar useful chemicals or proteins. Disease control: Understanding genetic similarities can explain disease spread and help develop treatments. Crop improvement: Helps identify related plants to breed for higher yield and disease resistance. Biological control: Identifies natural predators or parasites to manage pests effectively. Species protection: Enables laws to protect newly identified species from poaching.  Invasive species prevention: Helps detect and stop harmful species from entering new ecosystems. 7 Characteristics of All Living Things: 1. Movement 2. Respiration 3. Sensation 4. Growth 5. Reproduction 6. Excretion 7. Nutrition The 3 Domains: A new category called "Domain" was created.  The Archaea and Bacteria kingdoms, both made up of prokaryotic cells, were so different that they became separate domains. The other kingdoms (Animalia, Plantae, Fungi, Protista), which consist of eukaryotic cells, were grouped together in the Eukarya domain. Are all prokaryotes also single-celled? Yes. Are all single-celled organisms also prokaryotes? No. Do all plant cells do photosynthesis? Yes. True OR False? Only plants can make their own food. False. (Some bacteria and algae also do.) Dichotomous Key: helps identify characteristics of organisms with only two answers/parts ‘Dichotomy’ means: divided into two parts. ‘Key’ means: a tool for identification. It uses a series of two-part statements to describe organisms. For example: yes & no. The user makes choices based on characteristics, leading them to a new branch. Ultimately, the user identifies the organism. Types of Biodiversity Species Diversity: variety and abundance of species in an areas Genetic Diversity: a variety of inherited characteristics (genes) of the same species (interbreeding) making each individual unique Genetic Diversity Protects against Disease Helps survival by adapting to environmental changes Lack of genetic diversity More individuals suffer from same cancer Reduction in population Classified as endangered species Could lead to extinction Gene Pool- genetic variation in a population; group of the same species in an area Ecosystem Diversity: variety of ecosystems in their environment, and how they interact with each other more reliable services (pollination, clean water), more resilience balances external issues (invasive species, diseases) Biotic factors: ○ Living things, like interacting populations of different species. Abiotic factors: ○ Non-living things that affect ecosystems, such as: Altitude (height above sea level) Latitude (distance from the equator)  Soil nutrients (quality and type of soil) Light levels (amount of sunlight available) Viruses & Prions Viruses are non-living (to some scientists) **not apart of the six-kingdom classification system** Depend on (infecting) the internal working cells (prokaryotic & eukaryotic) Invades cells and uses the host’s functions to survive and reproduce The virus can’t survive without a host(grow/reproduce) Viruses have 2 simple things: strands of DNA or RNA with a protective coat All viruses have a protein coat and nucleic acid Nucleic acid: in very centre, either a single molecule of DNA or RNA (only one or the other) the only active part of the virus The effectiveness of a virus depends on the nucleic acid, the ability to choose a host is controlled by the protein coat Every living thing is prone to viruses The Capsid aka. Protein Coat is the outer part, which protects the nucleic acid Some specialized viruses (like influenza, mumps) have an outer layer called an envelope Forms from the host cell’s membrane as the virus leaves the cell. Helps the virus infect new host cells by merging with their membranes Classification of viruses depending on the type of host: Plant viruses Animal viruses Bacteria viruses Pathogenic viruses Pathogenic, spherical or polyhedral Pathogenic viruses in bacteria are Rod-shaped, contains (polygons) shaped called bacteriophages nucleic acid: RNA Some Capsid surrounded by envelope Nucleic acid: DNA nucleic acid: either DNA or RNA Viruses replicate in the host cell to make copies inside Lytic Cycle: viruses reproduce by infecting a host cell, using the host cell's machinery to create more copies of itself, ultimately destroying the host cell. 1. Attachment: The virus attaches to the host cell's surface. 2. Entry: The virus injects its genetic material (DNA or RNA) into the host cell. 3. Replication: The host cell is forced to replicate the virus's genetic material and produce viral proteins (like the capsid and tail). 4. Assembly: The newly made genetic material and proteins are assembled into complete virus particles. 5. Release: The host cell bursts open (lysis), releasing the new viruses to infect other cells. Some viruses have a more complex replication cycle with 2 phases: lytic phage and lysogenic phase Lytic phase: virus infects host cell to replicate genetic material, making new virus particles Ends up bursting (lyses); releasing the new viruses to infect other cells Lysogenic phase: instead of immediately entering into the lytic cycle, the virus inserts genetic material into the host’s DNA As the cell divides, the DNA is passed to the daughter cells Oncoviruses - cancer causing viruses from altering host cell’s DNA Causes uncontrolled cell growth and formation of tumours Some caused by DNA viruses, some caused by retroviruses (RNA) Majority of cervical cancers are caused by certain types of HPV (Human Papillomavirus) Spread through sexual contact 40/100 types of HPV and infect genital area → genital warts 15 HPV types are linked to cervical cancer AIDS (Acquired Immune Deficiency Syndrome): viral disease spread through sexual contact ← caused by HIV (Human Immunodeficiency Virus) ○ Spread through blood transfusions, sexual contact, mother to child pregnancy, breastfeeding  HIV attacks the T4 helper T cells; important for immune system defense The immune system weakens, making it harder to produce antibodies, more likely to get infections No cure for AIDS, but there are treatments HIV - a retrovirus Contains enzyme reverse transcriptase, converts viral RNA to complementary DNA Viral DNA becomes part of host cell’s chromosome → provirus As host cell divides, the new cells DNA are carried in the provirus Pro viruses can enter the lytic cycle and damaging it, weakening the immune system Bacteriophage (phage): a virus that infects bacteria Some follow the lytic cycle or the lysogenic cycle, and some viruses follow both cycles ○ In the lytic cycle (T4 phage); bacterial cell is destroyed (lysed) ○ Once bacterial cell bursts, new bacteriophage viruses release and infect new bacteria Used as alternative for antibiotics Used to treat multidrug resistant bacterial strains Neurodegenerative diseases: illness remains inactive in the body for decades They don’t get destroyed in after exposure of radiation Stanley Prusiner discovered a new type of disease cause: prion These prions are hard to get rid of, even with heat/radiation Prions - abnormal, misfolded proteins that can cause diseases Usually are in the body, but these prions get misfolded; changing shape to become harmful ○ Misfolded prions cause more to misfold Can cause neurogenetic diseases (brain damage) in humans and animals No DNA or RNA Encephalopathy: brain disease that causes altered mental state Causes: - Infections - Lack of oxygen (anoxia) - Metabolic problems - Toxins, drugs - Physiological changes - Trauma Transmitted: - Animal-to-animal: Through infected tissue (brain/spinal cord)  - Animal-to-human: Eating infected animal tissue Human-to-human: Rare, contaminated medical equipment. How viruses affect us Impact on Plants: Cause diseases in plants (like wheat viruses) Crop damage → Food shortages Impact on Humans: Cause diseases (HIV/AIDS, Polio, COVID-19, Flu, Swine Flu) ○ Symptoms: fever, fatigue, respiratory and immune system issues Biotechnology: Gene Cloning: viruses insert genes into host cell to replicate Gene Therapy: Altered viruses deliver healthy genes in cells to treat genetic disorders Comparing Bacteria and Archaea Bacteria and Archaea are both prokaryotes (no nucleus) Shapes: Spheres: cocci/coccus Rods: bacilli/bacillus Spiral shapes, cubes, pyramids (bacteria);  plates, rods, changeable (archaea) Aggregation patterns: Diplo- (pairs), Staphylo- (clusters), Strepto- (chains). 2 Types of Gram Staining Bacteria: 1. Gram-positive: Purple stain; thick peptidoglycan wall, made of sugar + amino acids 2. Gram-negative: Pink stain; thin peptidoglycan under an outer membrane. Archaea Bacteria Cell Wall: no peptidoglycan; cell wall is Cell Wall: Has peptidoglycan cell wall different Gas exchange: Gas exchange: Methanogenesis (methane production) Photosynthesis (e.g., cyanobacteria produce Digestive tract of animals sugar & oxygen) Habitat: Habitat: Extremophiles; live in extreme environments Mesophiles; live in moderate environments Thermophiles (heat), acidophiles (acid) Can live in environment with & without halophiles (salt), Can live in environment oxygen with & without oxygen Reproduction: Reproduction: Binary fission Binary fission - Very fast asexual reproduction - Very fast asexual reproduction - One cell splits → two daughter cells - One cell splits → two daughter cells Conjugation Conjugation - Genetic material exchange (not - Genetic material exchange (not reproduce) reproduce) - Two cells connect, one transfers DNA - Two cells connect, one transfers DNA to the other to the other - Increases genetic diversity - Increases genetic diversity (exchanging traits) (exchanging traits) Plasmids Small DNA loops separate from chromosomes. Transferred during conjugation, adding genetic variation. May carry antibiotic resistance genes. Endospores Bacteria form hard-walled endospores under harsh conditions.  Provide dormancy & resistance to extreme environments. Bacteria and Human Health Examples: ○ Botulism: Caused by Clostridium botulinum (anaerobic bacteria) and resistant endospores. ○ Lyme disease: Spread by ticks. Bacteria and the Environment Decomposers recycle nutrients. Cyanobacteria: Oxygen production via photosynthesis, transforming the environment billions of years ago. Archaea in Biotechnology Enzymes from archaea resist extreme conditions. Applications: Polymerase Chain Reaction (PCR) to amplify DNA sequences. KEY TERMINOLOGY 1. Morphology: The shape and structure of cells. 2. Cocci: Spherical-shaped cells. 3. Bacilli: Rod-shaped cells. 4. Peptidoglycan: A sugar and protein layer found in bacterial cell walls.  5. Gram Staining: A method to classify bacteria based on their cell wall structure (Gram-positive = purple, Gram-negative = pink). 6. Binary Fission: Asexual reproduction where one cell splits into two. 7. Conjugation: Exchange of genetic material between two cells. 8. Plasmids: Small loops of DNA in bacteria/archaea, often carrying useful genes (e.g., antibiotic resistance). 9. Endospores: Protective structures formed by some bacteria to survive harsh conditions. 10.Cyanobacteria: Photosynthetic bacteria that produce oxygen and change Earth’s atmosphere. 11. PCR (Polymerase Chain Reaction): A technology using archaea enzymes to copy DNA millions of times. Comparing Bacteria and Archaea Eukaryotes helped increase biodiversity Endosymbiosis: one cell engulfs a different smaller cell, and lives inside to help the bigger cell. Becomes an organelle in the bigger cell (mitochondria, chloroplast) Origin with evidence: mitochondrion was a free-living bacterium that got swallowed by the larger cell, but stayed inside and became apart of this  The host cell get energy from the mitochondrion, and the mitochondrion go protection and nutrients from the host cell Mitochondria - aerobic bacterium (uses oxygen), gets energy from sugar to power the cell through cellular respiration Chloroplast - originally a cyanobacterium; turns sunlight into energy through photosynthesis These makes the host cell more efficient to produce energy Evidence for the endosymbiotic theory: 1. Membranes: Chloroplasts and mitochondria have membranes like prokaryotes. 2. Ribosomes: They have ribosomes similar to those in prokaryotes. 3. Reproduction: They reproduce independently through binary fission, like bacteria. 4. DNA: They have circular chromosomes with genes similar to prokaryotic DNA.