1-Biology Basics F24.pdf

Introduction To Biology Lecture 1  Introduction -Biology: bio = life, logy: study. -Biology is the scientific study of life. -Biology is based on the principles of: *Evolutionary changes of life *Adaptation of life -What is Life? ...

Introduction To Biology Lecture 1  Introduction -Biology: bio = life, logy: study. -Biology is the scientific study of life. -Biology is based on the principles of: *Evolutionary changes of life *Adaptation of life -What is Life?  I- What is Life? How to Define Life? -With respect to Life, Earth contains mainly two things: *Living things = life, e.g.: Man, insects, bacteria *Non-living things, e.g.: rocks. -Life exists with many varieties and forms on earth: Animals, Bacteria, Plants, Fungi, Protozoa, etc… -Although life is diverse, all forms of life on earth: *Share the same chemical composition *Obey the same universal laws of chemistry and physics. -Life can be characterized by several criteria. Some of these criteria are: Rocks  I- How to Define life - Criteria of Life: Nature of Life *Life can be defined by: Nature or types of Life: -Animals, such as Man, Fish, Insects, Birds -Trees, Plants, Algae -Bacteria, such as E. coli -Fungus such as Mushrooms, Yeast -Protozoa/Protists such as Amoeba, Paramecium. Protist  I- How to Define life - Criteria of Life: Location of Life *Life can be defined by: Water The location of life, that is, where life exists: -Liquid: Oceans, rivers, lakes, ponds, thermal vents, -Ice -Land, ground, underground, *Air Land Ground Ice Thermal vents Underground Air  I- How to Define life - Criteria of Life: Observation Hooke’s *Life can be defined by: Microscope Life Observation, that is, the size of life -Visible to the Naked eye: Man, Animals, Plants, Fungi -Visible only with a Microscope: Bacteria, Protozoa Leewenhoek’s Microscope  I- How to Define life - Criteria of Life: Feeding *Life can be defined by: Ways of Feeding: nutrition -Take food in and digest it, e.g.: Man -Ingest (absorb), e.g: Amoeba -Photosynthesis, e.g.: Plants -Others feed by diffusion, e.g.: Bacteria. Amoeba: Man: Digestive System Pseudopods Bacteria: Diffusion Plants: Photosynthesis  I- How to Define life - Criteria of Life: Reproduction *Life can be defined by: Ways of Reproduction -Sexual, e.g.: Man. Meiosis -Asexual, e.g.: >Bacteria, Binary fission >Fungi: mitosis, budding Binary Fission Bacteria Budding Yeast Meiosis & Mitosis  I- How to Define life - Distinguish living and non-living things -Our planet Earth contains essentially two things: *Living things = life (e.g.: man) Living thing: The Rock *Non-living things (e.g.: rocks) -Living things are distinguished from non-living things by the following criteria: Non-Living thing: a Rock  I- How to Define life A- Living organisms are organized -The level of organization of living things starts with the atom. -Organization is maintained all the way up to the Biosphere. Atom>Molecule>Cell>Tissue>Organ> Organ System >Organism > Population>Community>Ecosystem> Biosphere. -Some organisms are Unicellular = 1 cell: e.g., Paramecium, Bacteria, Yeast, Amoeba…. -Others are Multicellular/Pluricellular = Many cells: e.g.: Man. -There is no such organization for non-living things on earth.  I- How to Define life - B- Living Organisms have Emergent Properties -In the life hierarchy, each level of Organ System: Brain biological organization builds upon the previous level and becomes more complex and specialized. -Moving up the hierarchy, each level acquires new properties called emergent properties = a function or quality that emerges as the biological complexity increases. Example: * a nervous cell: property = communication, * the nervous system: brain, emergent property: mind, think, cognitive, compute, etc.. Emergent properties: Cognitive, mind, etc. -These new properties still obey the same laws of chemistry and physics. -Example: non-living thing such as coal vs. a living- thing such as a Worm. When coal is cut into pieces, it still retains its coal properties. When the Worm is sliced into pieces: it no longer lives or functions… In other words: “In the living world, the whole is more than the sum of its parts” Nervous Cells Nervous Tissue  I- How to Define life - C- Living things acquire Food and Energy -Living things cannot function without an outside source of Nutrients and Energy -Food provides nutrients, which are used as the source of Energy. Energy allows the organism to do WORK and maintain itself. -Through the metabolism of food, living things use nutrients to make their own products. -Metabolism = Catabolism (decomposition, frees energy) and Anabolism (synthesis, consumes energy.) -The main source of energy for all life on earth is the Sun. Plants and other organisms (bacteria, algae) capture sunlight and manufacture organic products, a process called photosynthesis, e.g.: plants transform solar energy into chemical energy, and synthetize Glucose, a highly energetic molecule. -All forms of life on earth acquire energy by metabolizing nutrient molecules made by photosynthesizers. -Non-living things, such as a rock, do not need energy, do not do work. I- How to Define life - C- Living things acquire Materials and Energy  I- How to Define life - D- Living things maintain Homeostasis -To survive, all organisms must maintain a state of biological balance, called homeostasis. -For instance, the following homeostasis factors, temperature, acidity, blood sugar, humidity, moisture level, etc., must be within a tolerable range otherwise death will occur. -Most of these factors and controlled by the nervous system through adjustments and alerts. -Non-Living things have no homeostasis.  I- How to Define life - E- Living things sense and respond. -All living organisms have the ability to sense and respond/react. -Response or reaction often results into movement for survival: *move against hunger, thirst *move towards food *move away from threat, danger (predators, cold, heat, etc…) -Example: Plant leaves move toward the sun to capture solar energy. -Non-living things do not sense.  I- How to Define life - F- Living things reproduce and develop -Life comes only from life. -Some forms of life split in half, thus Bacteria: generating new organisms: Binary fission *Bacteria, unicellular, reproduce by binary fission, asexual reproduction. *Yeast: unicellular, budding, asexual reproduction -In most multicellular organisms, reproduction results from pairing of sperm Cell Reproduction Eukaryotic cells cells from one partner with the egg cell from another. The resulting fertilized egg develops into multicellular adult after a certain time. -Genes carry the information necessary to make the new organism. Genes are made of DNA (deoxyribonucleic acid.) -Non-living things do not reproduce. Mules cannot reproduce Birds & Eggs Mammals Is a mule a living thing?  I- How to Define life - G- Living things have adaptations -Adaptation: better modifications that make organisms better able to function in a particular environment. Penguins Birds -Organisms respond to changing environment conditions by developing new adaptations. -Adaptation results in evolution of life. -Evolution: All forms of life have the capacity Cheetah Zebra to evolve and persist >> Natural Selection. Human Evolution -Non-living things have no adaptation, no evolution.  II- Evolution: The unifying concept of Biology - Evolutionary Tree of Life -As mentioned before, all forms of life on earth share common characteristics. This Prokaryotes Cells with no nucleus suggests that they all have a common Unicellular ancestor >> existence of an Evolutionary Tree of Life Eukaryotes Unicellular -Evolutionary tree: traces the ancestry of Cells with nucleus Unicellular or Multicellular life to a common ancestor. Pluricellular -Evolution is a unifying concept in biology because it can explain how organisms came Uni/Pluricellular from a single ancestor. Pluricellular  II- Evolution: The unifying concept of Biology - Evolutionary Tree of Life -As mentioned before, all forms of life on earth share common characteristics. This suggests that they all have a common ancestor >> existence of an Evolutionary Tree of Life -Evolutionary tree: traces the ancestry of life to a common ancestor. -Evolution is a unifying concept in biology because it can explain how organisms came from a single ancestor.  II- Evolution: - The unifying concept of Biology - Natural Selection Charles Darwin (British) 1809 – 1882 -Charles Darwin observed that Natural Selection was the process that made life modifications, adaptations and evolution possible. Example: here, plants adapt their leaf structure against the preying animal >> *Natural Selection against predators. *Goal of the selection: stay alive as a species  III- Organizing Diversity of Life on Earth -Because there are so many living things on earth, it becomes important to organize and classify them. -Taxonomy (arrange, usage) is the science of identifying and grouping organisms according to certain rules. -Carolus Linnaeus is the father of taxonomy. Carolus Linnaeus (Swedish) -Systematics studies evolutionary relationships between (1707 – 1778) organisms. -Basic classification categories go from: least inclusive (species) to most inclusive (domain). Basically: Species = least inclusive>genus>family>order>class> phylum>Kingdom>Domain = most inclusive. -Least inclusive: species is only one organism. Most inclusive: Domain, contains many organisms. (Species is like a file; a domain is like folder, a folder contains many files) Levels of Classification  III- Organizing diversity of Life on earth: The 3 Main Domains: Archea, Bacteria, Eukarya -Biochemical evidence suggests there are only 3 life domains on earth: Bacteria, Archaea and Eukarya. -Bacteria and Archaea are also called Prokaryotes: they lack a nucleic membrane around their DNA, no nucleus, all are unicellular. -Eukaryotes: they possess a nucleic membrane around their DNA, have a nucleus. Can be unicellular or Pluricellular. -Scientists use an italicized binomial (two words) nomenclature to assign a taxonomical name to each living organism, mostly based on Latin language, e.g.: *Homo sapiens: Man; *E. coli, bacteria  Domains of Life Domain Archaea okaryotes Pr – Contains unicellular prokaryotes that live in extreme environments Prokaryotes lack a membrane-bound nucleus. Domain Bacteria – Contains unicellular prokaryotes that live in otes all environments Eukary Prokaryotes lack a membrane-bound nucleus Domain Eukarya – Contains unicellular and multicellular eukaryotes Eukaryotes contain a membrane-bound nucleus.  Domain Archaea Prokaryotic cells of various shapes Adaptations to extreme environments Absorb or chemosynthesize food Unique chemical characteristics Example: Methanosarcina mazei, an archaean 1.6 m  Domain Bacteria Prokaryoticcells of various shapes Adaptations to all environments Absorb, photosynthesize, or chemosynthesize food Unique chemical characteristics Example: Escherichia coli, a bacterium 1.5 m Domain Eukarya IV- How the Biosphere is organized Example: The Grassland Ecosystem *Matter (chemical) recycles *Energy flows  IV- How the Biosphere is organized. - The 2 main biologically diverse Ecosystems Rain Forest Ecosystems (green on map) Coral Reef Ecosystems (red on map)  IV- How the Biosphere is organized - Biodiversity -Biodiversity is the total number of species, the variability of their genes, and the different ecosystems in which they live. -The present diversity on earth is estimated at 15 million species, of which only 2 millions are known and named. -Human populations destroy ecosystems with deforestation to build houses, roads, wood exploitation (timber), oil platforms, mines and costal touristic resorts. -Extinction is the death/disappearance of a species. -Today, planet earth loses 400 species/day due to human activities, and 38% of all current species are in danger on extinction.  The Effect of Human Activities on Coral Reefs a. Healthy coral reef 1975 Minimal coral death 1985 Some coral death 1995 Coral bleaching with 2004 Coral is black from With no fish present limited chance of recovery sedimentation; bleaching still evident b. Unhealthy coral reef  Review for Lecture 1: Biology Basics -Understand the meaning of the following words: Biology, taxonomy, systematics, unicellular, multicellular, prokaryote, eukaryote, homeostasis, -Criteria to define life: nature of life, location, reproduction, observation, energy, etc… -Differences between living and non-living things -Level of organization of life: from the atom to biosphere -Understand what Emergent property means. Example: nerve sells and the brain -Domain = most inclusive, species = least inclusive -The three main domains: Bacteria-Prokarya, Archaea-Prokarya and Eukarya -How we write the scientific names of species; italics, 2 words, first letter of the first word is capitalized. Example: Homo sapiens 32