Classification History • Taxonomy: Branch of biology that groups all life according to their characteristics and history • All life on earth is placed into 1 of 6 kingdoms: • Eubacteria • Archaea • Protista • Fungi • Plants • Animals
Carolus Linnaeus • Developed classification system based on physical features • Binomial Nomenclature: System of giving every organism 2 names • 1st word: Genus (broad) • 2nd word: Species (specific) • Example: House cat • Genus: Felis (cougars, lions, tigers, cheetahs, etc…) • Species: catus
Binomial Format • When Writing: • Genus capitalized • species lowercase • Underlined entirely Ex: Homo sapiens • When Typing: • Same, except use italics Ex: Homo sapiens Bos taurus
Taxa • 7 individual levels (taxa) used to classify organisms Kingdom (broadest) Phylum Class Order Family Genus Species (specific) • Allows relationships to be clearly seen
How is Life Classified Today? • Taxonomy: grouping life according to shared traits (not just physical) • 1) Morphology: studying the form and structure of organisms • Comparing the morphology (traits) of different species shows similarities and/or differences Mammals
Morphology Shows Non-Relationships Also! Dolphins are not FISH!
2) Biochemical Evidence • Comparing DNA, amino acids, & proteins • DNA mutations occur at known rates • Splits in evolution can be estimated based on how different DNA between 2 organisms is • More different the DNA…longer ago common ancestor
3) Embryo Development • Patters of development studied to identify relatedness • Blastopore (1st opening of embryo) shows humans & starfish are more related than humans & squid Mouth Anus Anus
Phylogeny all have amniotic eggs • Defined: Evolutionary history of an organism • Shown by cladograms • Group life according to similarities How many traits does a primate & amphibian share? Which organisms do not have amniotic eggs?
1) What does an amphibian & crocodile have in common? Vertebrae, Bony skeleton, Four limbs • 2) List the traits of a ray-finned fish. Doesn’t have 4 limbs, has bony skeleton, has vertebrae
Virus: A biological particle composed of nucleic acid and protein Intracellular Parasites: organism that must “live” inside a host Topic 2: Viruses
Reproduce Have nucleic acid Adapt to surroundings Have organization Not made of cells or organelles Can’t reproduce on own Don’t metabolize energy Don’t perform cellular processes Are viruses alive? No Yes
All Have: 1) Capsid: coat of protein that surrounds nucleic acid 2) Nucleic Acid: RNA or DNA Some Have: Tail Fibers: Used for attachment (not legs) Shapes vary Virus Parts
1st Step: Attachment Virus attaches to a cell receptor No attachment = No infection The Lytic Cycle
2nd Step: Entry Virus enzyme weakens cell membrane Genetic material (DNA or RNA) enters host cell The Lytic Cycle
3rd Step: Replication Virus DNA/RNA makes virus proteins by transcription/ translation The Lytic Cycle
4th Step: Assembly New virus proteins are assembled into new viruses The Lytic Cycle
5th Step: Release Virus enzyme causes host to burst Viruses are released to find new host…Cycle repeats The Lytic Cycle
The Lysogenic Cycle 1) Attachment: Virus attaches to host cell Host cell DNA Pro-phage 2) Entry: Virus nucleic acid enter the cell, but combines with host cell DNA.
The host cell divides by mitosis, making a copy of the prophage each time. Pro-phage Pro-phage Pro-phage Two infected cells.
Two cells divide my mitosis to make 4 infected cells. Pro-phage Pro-phage
Virus DNA eventually becomes active and starts to create viruses following the stages of the lytic cycle. All infected cells burst, releasing many more viruses to restart the cycle.
Prokaryote Cells w/o nucleus & membrane bound organelles Chromosome & plasmids float freely in cytoplasm Ribosomes create proteins Flagella used in movement Pili act as anchors Connect to other cell during conjugation Endospore “cocoon” to protect DNA in harsh times Cell Structure
Many bacteria grow in colonies 3 Basic Shapes: 1) Rod 2) Spherical 3) Spiral Bacterial Shapes
Bacteria Asexual Reproduction Binary Fission: asexual reproduction where one cell splits into two cells Both cells have identical sets of DNA Less genetic diversity Click pic
Bacteria Sexual Reproduction Conjugation: process where DNA is exchanged between bacteria cells Cells connect by pili DNA duplicated and then exchanged Creates genetic diversity Gene to resist ampicillin Gene to resist ampicillin
Anaerobic Obligate anaerobic = cannot live in oxygen Aerobic Facultative aerobic = can live with or without oxygen Obligate aerobic = must live in oxygen Respiration The bacteria that causes TB lives in your lungs…which type is it?
Identifying Bacteria with Gram Staining Gram negative: stains pink extra outer layer harder to treat • Gram positive: • stains purple • lack extra covering • easier to treat
Brush, Floss, & Rinse Your Teeth! GINGIVITIS HEALTHY MODERATE PERIODONTITIS ADVANCED PERIODONTITIS
Antibiotic Resistance • Problem: Bacteria are adapting to live with the antibiotics • Causes: • 1) Using antibiotics on viruses or without prescription • 2) Not completing prescription • 3) Overuse on farm animals • Importance: Bacteria infections harder to treat
Most bacteria killed Strong Survive Resistant Bacteria Only Strong Reproduce
Protista in General • Usually unicellular • Reproduction: • Asexual, Sexual, Both • Kingdom for life that doesn’t fit in animals, plant or fungi kingdom • Mostly aquatic life • 3 main categories based on feeding • Animal-like • Plant-like • Protista-like
Animal-Like Protista (Protozoans) • Aquatic, unicellular • Heterotrophic • Feed & ingest prey • pathogens, parasites, predators • 3 subcategories based on how they move • 1) Pseudopods : have pseudopodia (false- feet) • Engulf by phagocytosis • 2) Flagellates: have flagella • 3) Ciliates: have cilia
Pseudopod Video Clips File title: Amoeba2 File title: Amoeba4
Ciliates Video Clip File title: Paramecia2 File title: Rotifer2
Flagelletes Video Clip File title: Euglena2 File title: Euglena
Animal-Like Protista & Disease • Malaria: Infected mosquito bites • Fever, vomiting, coma, death • Sleeping sickness: bite of tsetse flies • Coma & death
Plantlike Protista • AKA: Algae • Perform photosynthesis with chloroplasts • Provide ~ ½ the O2 on earth • Most unicellular • Phytoplankton: basis of aquatic food chains (producers) • Few multicellular • Seaweed, kelp • Why not plants? • No true leaves, stems, or roots • most unicellular
Fungus-like Protista • Heterotrophs • Decomposers: recycle nutrients • Absorb nutrients • Moist environments • Slime Molds: large (~1 meter) single celled mass of cytoplasm • Water molds: can be parasitic • Potato blight: disease & the Irish potato famine
Fungi Structure & Basics Hyphae: thin strands of cells that make up the fungus body Hyphae spread into a larger mass (mycelium) Fruiting body: Above-ground reproductive structure Cell wall of chiton (common to animals) Heterotrophs: hyphae release enzymes to absorb nutrients Classification determined by sexual reproduction methods strands of hyphae
Zygote Fungi Bread Molds Some help “fix” nitrogen in atmosphere Asexual Reproduction Sporangia produce spores Spores can grow into new hyphae when released . . .
Haploid spores land Hyphae grow into a mat of mycelium Sporangia grow from the mycelium . Sporangia release spores . . . ground