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Transcript
What is Biology? What is Biology, you ask? Biology is the study of life. Living things are called organisms. Organisms include bacteria, protists, fungi, plants, and animals. Viruses are not alive – they are not organisms. 2 The seven characteristics of life All life is made of cells. All life must reproduce. All life has heredity based on one universal genetic code (DNA). All life has metabolism. All life must respond to environmental stimuli. All life has homeostasis; it must maintain a stable internal environment . All life must evolve; that is, species must change over time. 3 Conservation of Mass and Energy in Biological Systems Mass and energy cannot be created or destroyed but can be converted from one form to another. Energy is conserved as it flows through an ecosystem. Energy moving through an ecosystem changes from light energy to chemical to thermal and mechanical energy. All organisms respond to environmental stimuli: abiotic and biotic factors Food web Interdependence in Ecosystems All life must obtain energy and has metabolism Note units of energy here. 90% of energy is not transferred to next level. Level 4 3 2 1 Organisms occupy trophic (energy) levels in the environment. They use energy (90%) for themselves and also release heat in the process. For these reasons, only 10% of the energy is available to the next higher trophic level of the energy pyramid. 8 Animals cannot use light energy to make sugar. Animals depend on plants for food. Decomposer – a consumer that puts materials from dead plants and animals back into the soil, air, and water Ecology is the study of relationships among organisms and their environment. Ecosystem is made up of all the communities in an area and the nonliving things with which they interact. When organisms rely on each other, they are interdependent. (food chain, food web, energy pyramids) Biodiversity is the variety of life in an ecosystem. (coral reefs, rain forests) Symbiosis occurs when two or more different species have a close relationship. (Co-evolution) Mutualism – both species benefit Commensalism – one species benefit and the other is not harmed or helped Parasitism – one species benefits while harming the other one. Metabolism: the sum of all the biochemical reactions in an organism All organisms require energy. 1. Autotrophs get their energy from the sun. Photoautotrophs (algae , plants) use sunlight to make food (carbohydrates: photosynthesis) Chemoautotrophs (usually bacteria) use chemicals such as iron & sulfur as their energy source to make food(carbohydrates). These organisms are the producers of ecosystems that are in the dark(volcanic thermals at the bottom of the ocean, caves) 2. Heterotrophs must consume food for energy Herbivores – consume only plants Carnivores – consume only other animals (meat) Omnivores – consume both 12 3. Decomposers – break down the complex compounds of dead and decaying animals. They also break down energy into molecules that are then returned to the environment. Carbon as CO2, Nitrogen,phosphorus Bacterias, Fungi, vultures, maggots, hyenas… An ecosystem consists of all the organisms living in an area, as well as the nonliving parts of that environment. Biotic(living)Factors Abiotic(non-living) Factors Natural Changes in Ecosystems Biotic factors – living things Abiotic factors – nonliving things Limiting factors – anything that limits the ability of an organism to live in a certain place. (space,food, temperature, shelter) Successions – normal, gradual changes that occur in the types of species that live in an area. There are 2 types. Primary succession Ecosystems go through successions over time and will slowly return to their original climax state if disturbed. New soil must first be created in primary succession, after volcanic eruptions or ice sheets scour the earth. Secondary succession Occurs in areas that previously contained life and still contain soil. After a fire, soil remains, and a previously established ecosystem can return relatively quickly. Natural Selection and Species Diversity Evolution is the process of change over time as a result of natural selection. Natural selection is a mechanism for change in populations. It occurs when organisms with favorable variations (DNA mutations)survive, reproduce, and pass their variations to the next generation. There are 3 types of natural selection: 1. Stabilizing selection – favors average individuals 2. Directional selection – favors one of the extreme variations 3. Disruptive selection – individuals with either extreme of a trait’s variation are selected for survival. disruptive A population that is in genetic equilibrium is not evolving. Any factor that affects the genes disrupts this equilibrium, which results in evolution. Mutation is a mechanism for genetic change in the DNA. Environmental factors such as radiation, chemicals can cause mutations. 6 Best proofs of Evolutions (2) (1) Fossil Record Convergent Evolution (3) Comparative Anatomy Evidence of Evolution (6) Molecular Comparisons (4) (5) Embryological Development Vestigial Structures All life must evolve Thanks to successive mutations in their DNA, genetic drift , natural selection and sexual reproduction, groups of organisms (not individuals) change over time in order to survive within changing environments. This is Charles Darwin’s idea of evolution and survival of the fittest. In addition long isolation of populations is needed to create new species. Some evidences for evolution are: 1. Fossil records show that organisms with similar to a structures (homologous parts) trace back common ancestor. Mammals, birds, reptiles & amphibians trace back to fish, which go back further, eventually to bacteria. 25 2)Homologous structures (Divergent evolution) Homologous structures, body parts similar in underlying structures but different in functions, indicate an ancient common ancestor. Over time (millions of years, usually), adaptations to new environments cause bones (or beaks) to change. 3)Analogous structures(Convergent evolution) Body parts of organisms that do not have a common evolutionary origin but are similar in function because they evolved in similar medium and conditions(air, water, land). Ex: flippers of dolphins and fins of fish, etc… Examples of Convergence: • Whales and Fish • Marsupials and Placental Mammals • Counter-shading coloration and other forms of camouflage • Mimicry and camouflage • Hedgehogs and Porcupines • • Cactus Beaver and Capybara Plants : Desert adapted Euphorbias Vs. cactus Euphorbia 4)Evidence Comparative Embryology for Evolution - Comparative Embryology Similarities In Embryonic Development= Common ancestor 29 5)Vestigial Structures • • • • Mutations are always producing new body forms each generation. Sometimes, environmental changes and mutations combine to provide new opportunities for species. As species evolve to fill different niches in their changing world, we would expect their bodies to change over many generations. Vestigial structures are body parts that are reduced in size and function. Mutations that reduce the size of such structures are not harmful and may actually be of a benefit to the individuals that inherit them. Click on one of the examples below to learn more. Fossil whale legs Human coccyx, Snake leg spurs Reduced eyes of troglobites Mammal male Wings of ostriche breasts Home 6)Comparative Biochemistry Comparison of Proteins & DNA Molecular evidence of evolution. Comparison of DNA or AA(amino acids in proteins) sequence between different species – Bird & human DNA are only 60% identical – Plant and Human DNA are only 10% identical Comparison of Proteins(“cytochrome C”) & DNA • • • • Even when one considers a species as distantly related to animals as a yeast, there are still similarities to be found. Half of the genes in a yeast are also found in humans. Experiments have shown that mutant yeast can be fixed by inserting the human version of a gene to replace their defective gene. These genes have been inherited from our common ancestor, which lived well over half a billion years ago. Yeast Primates Home 7)Evolution of resistance to pesticides/herbicides and antibiotics in response to selection 34 8)Bio-geography/Speciation/Adaptations 35 Levels of Organization copyright cmassengale 37 copyright cmassengale 38 Phylogenic tree /Cladogram Derived Characteristics Protists • Unicellular Eukaryotes • Can be autotrophic or heterotrophic • Reproduce mostly asexually Fungi • Multicellular eukaryotes (yeast are the only unicellular fungi) • Heterotrophs • Reproduce asexually and sexually Plants • Multicelluar eukaryotes • Autotrophs • Reproduce sexually and asexually a protective covering that surrounds the seed makes seeds. makes the plant's food. anchor the plant in place and absorb water and other minerals from the soil. carries water and food to the rest of the plant. a protective covering that surrounds the seed makes seeds. makes the plant's food. anchor the plant in place and absorb water and other minerals from the soil. carries water and food to the rest of the plant. What Are the Parts of a Flower Most flowers have four parts Sepal – one of the leaflike parts that protects a flower bud and that is usually green Pistil – part of a flower that makes the eggs that grow into seeds Stamen – part of a flower that makes pollen Flower parts Pollen – tiny grains that make seeds when combined with a flower’s egg How Fertilization Occurs When a pollen grain reaches a pistil, it grows a thin tube to the ovary. Sperm from the pollen grain combines with an egg, and a seed forms. Fertilization – the combination of sperm from a pollen grain with an egg to form a seed Where does a fruit comes from>? Shoot Apical Meristem Simple Tissues – consisting of one cell type Parenchyma – thin walled & alive at maturity; often multifaceted. Collenchyma – thick walled & alive at maturity Sclerenchyma – thick walled and dead at maturity Sclerids or stone cells – cells as long as they are wide Fibers – cells longer than they are wide Epidermis – alive at maturity Trichomes – “pubescence” or hairs on epidermis Root Hairs – tubular extensions of epidermal cells Stoma position Gas exchange Oxygen Roots – function and structure Hold plant in position Absorb water and minerals from the soil Specialised cells to increase surface area for water intake Root hair cells (x150) Water is Polar Hydrogen _ Hydroge + • In each water molecule, the oxygen atom attracts more than its "fair share" of electrons • The oxygen end “acts” negative • The hydrogen end “acts” positive • Causes the water to be POLAR • However, Water is neutral (equal number of eOxygen and p+) --- Zero Net Charge ++ Hydrogen Bonds Exist Between Water Molecules • Formed between a highly Electronegative oxygen atom of polar water molecule and a Hydrogen atom of an other water molecule. • One hydrogen bond is weak , but many hydrogen bonds are strong Oxygen Hydrogen Oxygen Hydrogen Properties of Water • Cohesion(surface tension-surface film, water transport In plants) • Adhesion(water transport in plant) • High Specific Heat(resist Temp change) • High Heat of Vaporization(cools transpiration) • Less Dense as a Solid(ice body during floats, insulates) • Green house gas for the Earth All life has metabolism Sunlight is the ultimate energy for life on Earth. Photo-synthesis is carried out in the Chloroplast of producers such as algae, phytoplankton, plants. All life has metabolism Cellular Respiration (in Mitochondria) Through respiration, cells release the chemical energy stored in foods created by photosynthesis. 6O2 + C6H12O6 6CO2 + 6H2O + 36 ATP 58 Comparison of Photosynthesis and Cellular Respiration Photosynthesis video 6CO2 + 6H2O → C6H12O6 + 6O2 Cellular Respiration P + ADP + C6H12O6 + 6O2 video → 6CO2 + 6H2O + ATP Human anatomy The BRAIN Cerebral Cortex - The outermost layer of gray matter making up the superficial aspect of the cerebrum. Cerebral Cortex Cerebral Cortex http://www.bioon.com/book/biology/whole/image/1/1-6.tif.jpg The Cerebellum –helps coordinate voluntary movement and balance The Limbic System • Hypothalamus, pituitary, amygdala, and hippocampus all deal with basic drives, emotions, and memory • Hippocampus Memory processing • Amygdala Aggression (fight) and fear (flight) • Hypothalamus Hunger, thirst, body temperature, pleasure; regulates pituitary gland (hormones) Brain parts The Limbic System Hypothalamus neural structure lying below (hypo) the thalamus; directs several maintenance activities eating drinking body temperature helps govern the endocrine system via the pituitary gland linked to emotion (show video) The lobes of the cerebral hemispheres Planning, decision making speech Sensory Auditory Vision The Cerebral Cortex • • • • Frontal (Forehead to top) Motor Cortex Parietal (Top to rear) Sensory Cortex Occipital (Back) Visual Cortex Temporal (Above ears) Auditory Cortex A. Primary Motor Cortex/ Precentral Gyrus B. Broca’s Area C. Orbitofrontal Cortex Cortical Regions D. Primary Olfactory Cortex (Deep) E. Primary Auditory Cortex A. F. Wernike’s Area K. I. G. Primary Visual Cortex B. H. Visual Association Area H. G. I. Primary Gustatory Cortex J. Somatosensory Association Cortex K. Primary Somatosensory Cortex/ Postcentral Gyrus J. C. D. E. F. http://williamcalvin.com/BrainForAllSeasons/img/bonoboLH-humanLH-viaTWD.gif The Heart and the circulatory system The right and left sides of the heart are separated by a septum, or wall. The septum prevents the mixing of oxygen rich and oxygen poor blood. The Heart On each side of the septum are two chambers. The upper chamber (receives blood) is the atrium. The lower chamber (pumps blood out of heart) is the ventricle. Pathway of Blood Deoxygenated blood passes from the right atrium into the right ventricle and then goes to the lungs. From the lungs, blood moves back toward the heart into the left atrium to the left ventricle and then passes into the aorta to go to the rest of the body Immune response 1 1)The First Line of Defense skin, stomach acid, mucus 2) The Second Line of Defense White blood cells 3)The Third Line of Defense ~Antibodies~ Immune response( 3rd line of defense) Acquired Immunity 1)Active immunity: Antidodies are made by the body a)Natural : Because of memory T cells and Memory B cells, we are protected from getting sick twicw from the same disease b) Artificial : Men made vaccin made from dead organism , triggers a secondary immune response and create Memory B and T cell for soecific desease. 2)Passive immunity: Antidodies are made by an other individual and are “ bored” or “imported” by the host. 1a) Natural :When a new born baby is breast fed, the colostrum in the milk contains antibodies and memory cells from the mother b) Artificial : Serum made for deease such as yellow and dingue fever are made of antibodies taken from animals or previously sickk individuals . This serum are good only for a couple of month. All organisms are made of cells 75 All organisms are made of cells Cells are the building blocks of life. All cells come from pre-existing cells. Viruses (in red here) are not made of cells; they are not alive. 76 The cell theory states that all living things are made up of cells; basic units of structure and function in living things are cells that new cells can only be produced from living, existing cells. Cell membrane Separates the living from non-living environment. Made of protein and lipid On design mode double click on table Cellular organelles: Description and Function ORGANELLE LOCATION DESCRIPTION FUNCTION cell wall plant, not animal *outer layer *rigid, strong, stiff *made of cellulose *support (grow tall) *protection *allows H2O, O2, CO2 to pass into and out of cell cell membrane both plant/animal *plant - inside cell wall *animal - outer layer; cholesterol *selectively permeable *support *protection *controls movement of materials in/out of cell *barrier between cell and its environment *maintains homeostasis nucleus both plant/animal *large, oval *controls cell activities nuclear membrane both plant/animal *surrounds nucleus *selectively permeable *Controls movement of materials in/out of nucleus cytoplasm both plant/animal *clear, thick, jellylike *supports /protects cell organelles material and organelles found inside cell membrane endoplasmic reticulum (E.R) both plant/animal *network of tubes or membranes *carries materials through cell /rough ER contains ribosomes ribosome both plant/animal *small bodies free or attached to E.R. *produces proteins mitochondrion both plant/animal *bean-shaped with inner membranes *breaks down sugar molecules into energy vacuole plant - few/large animal - small *fluid-filled sacs *store food, water, waste (plants need to store large amounts of food) lysosome plant *small, round, with a uncommon membrane animal - common *breaks down larger food molecules into smaller molecules *digests old cell parts chloroplast plant, not animal *green, oval usually containing chlorophyll (green pigment) *uses energy from sun to make food for the plant (photosynthesis Golgi bodies both plant/animal Network of membrane Process protein and waste products Nucleolus both plant/animal Inside the Nucleus Chromosome both plant/animal Inside the Nucleus Centrioles both plant/animal In Cytoplasm Controls production of ribosomes Contains DNA Attach chromosome during cell division Cell membrane A cell must be able to obtain food and get rid of wastes through its cell membrane 80 Diffusion The movement of particles from a region of high concentration to a region of low concentration. Click here for video Examples: perfume in air, smoke in air, sugar in water, oxygen through cell membranes Passive transport: Osmosis Diffusion of water from an area of high concentration of water molecules to one of low concentration across a partially permeable membrane. Partially permeable means only some things can pass, not everything: usually small molecules with no charge, like H2O, CO2, & O2. “High” water concentration means that there are a lot of water molecules per same unit of volume. “Low” water concentration means that there is a lot of something dissolved in the water, so fewer molecules of water. video 82 Active transport: Diffusion(against the concentration gradient) of any molecules from an area of low concentration of that molecule to one of higher concentration across a partially permeable membrane using ATP as a source of energy. Ions pump such as sodium and Hydrogen . Endo, exo-cytosis and phagocytosis when a cell absorbs or excretes. Video1:Phagocytocys Video2: Active transport 83