Biology Mrs. Schalles Chapter 1 The Science of Life Most notes & images in this show from HOLT Biology text unless noted otherwise. Image from: http://www.le.ac.uk/bl/background2.jpg
Most topics that will be covered in Biology are introduced in chapter 1 I. The World of Biology A. Branches of Biology B. 7 Characteristics of Living Things II. 3 Themes in Biology A. Unity of life’s: Genetic Code & Classification B. Interdependence: Environment & Ecology C. Evolution: Darwin, Natural Selection, Adaptations III. Scientific Method • Tools & Techniques: Microscopes & Other tools
Biology- the study of living things Biologists study life on many levels- from molecular to global. We are beginning to solve puzzles- how does a single cell grow into a multicellular plant or animal, how the human mind works, how solar energy is converted into chemical energy- food, how organisms network in biological communities like coral reefs, what threatens life
I. The World of Biology A. Definitions 1. Biology- the study of life “bio” means “life, “-logy” means the study of. 2. The branches of Biology -something in the vast field of biology interests you & is important to your life. -Biologists study the food supply, microorganisms, plants, health, ecology, biochemistry & more. We’ll look at some of the many fields of biology.
Branches of Biology • Anatomy- study of body parts • Botany- study of plants • Bacteriology- study of bacteria • Cytology- study of cells • Ecology – study of environment • Embryology- study of development of individuals • Entomology- study of insects • Horticulture-study of growing • Immunology- study of immune system
Genetics – study of genes & heredity • Hematology- study of blood • Herpetology- study of snakes • Microbiology – study of microorganisms • Mycology- study of fungi • Pathology- study of abnormal structures or functions • Parasitology– study of parasites • Paleontology- study of formerly-living organisms like fossils and dinosaurs • Physiology-study of body part functions • Taxonomy- study of classification • Virology- study of viruses • Zoology -The study of animals
3. Organism- a living thing • Oldest fossil of a living organism- over 3.5 billion years old • Earliest Life on Earth-For millions of years- only characteristics - unicellular, aquatic, microscopic, simple, anaerobic (cannot live in oxygen)
B. 7 Characteristics of Living Things 1. Organization/ Cell theory 2. Response to stimuli 3. Homeostasis 4. Metabolism 5. Growth & Development 6. Reproduction 7. Evolution
1. Organization/ Cell theory Cell Theory – the theory that all living things • are made up of one or more cells, 1. Cells are the basic units of organisms 2. In a multicellular organism - cells specialized! 3. Cells come only from existing cells. Unicellular (single celled organism) Multicellular(many celled organism) -A cell is the smallest unit that can perform all life’s processes.
Organization -is the high degree of orderwithin an organism’s internal & external parts & its interactions with the world. Hierarchy of organization of living things • Atom • Organic Molecule • Organelle • Cell • Tissue • Organ • Organism **See pages 6-7 of your textbook
“Emergent Properties” • In the levels of the “hierarchy” there arenew characteristics that are not apparent at a simpler level: • Atom-Molecule-Organelle-Cell-Tissue-Organ-Organism “A living organism is a whole greater than the sum of its parts.” (cannot fully explain a higher level of order by breaking it down into its parts)
Cells are made of parts: • Atoms: Carbon (C), Nitrogen (N), Oxygen (O), Hydrogen (H), etc • Molecules -made of atoms:water- H20, Sugars like Glucose (C6H12O6), & large Proteins like Hemoglobin, C738H1166N812O203S2Fe(amino acids with a Fe ion) Phospholipids, DNA, etc • Organelles -made of molecules: Nucleus, Cell membrane, Chloroplast, Mitochondria, Ribosomes, etc.
Atom-Molecule-Organelle-Cell-Tissue-Organ-Organism health.yahoo.com health.yahoo.com web.jjay.cuny.edu www.scienceaid.co.uk www.answers.com www.search.com www.mie.utoronto.ca Health.yahoo.com http://orchard.sbschools.net/library/links/body.jpg
7 Characteristics of Living Things 2. Response to Stimuli • Stimulus- • a physical or chemical change in the internal or external environment. • that elicits or accelerates a physiological or psychological activity or response. • Response- • Reaction to stimulus agent or action • For example: The owl dilates pupils in the eye to keep the level of light entering the constant. ebiomedia.com www.birds.cornell.edu
B. 7 Characteristics of Living Things 3. Homeostasis --The ability or tendency of an organism or cell to maintain stable internal conditions (equilibrium )by adjusting its physiological processes. -conditions such as: temperature, pH, water content, uptake of nutrients by cells, etc. will be maintained in a constant range- usually different than outside environment.
Homeostasis Questions: What would happen if: -an amoeba could not maintain a different internal amount of water than it’s surroundings? *It would explode with too much water *It would shrivel up without enough water -what if a desert mouse could not maintain a different internal temperature than the environment? * freeze to death in cold night air * bake in the daytime heat.
Quick Lab- page 8Observing Homeostasis in Goldfish • Read through the lab explanation. • I will select the lab groups. • Do not abuse the fish. • Be very careful with the glass thermometers; be sure the temperature is the same as the labeled beaker. Do not kill the fish. Wipe up any spills. • Each person will hand-write a brief lab report (*see lab report format- no cover page or references needed) • Answer the 3 questions in the analysis section. fish.dnr.cornell.edu
Quick Lab Results: • Gills are a respiratory structure that consists of many blood vessels surrounded by a membrane that allows for gas exchange. • It is protected by a hard plate called the operculum. • The gills will move faster at higher temperatures. • There is less dissolved oxygen in warmer water. • The fish is taking in more water & therefore more oxygen. • The rate at which the gills move affects the amount of oxygen- the amount of dissolved gas in the fish blood.This maintains homeostasis.
B. 7 Characteristics of Living Things 4. Metabolism • is the sum of all the chemical reactions that take in and transform energy and materials from the environment.
B. 7 Characteristics of Living Things 5. Growth and Development • Growth of living things results from the division & enlargement of cells. • Development is the process by which an organism becomes a mature adult.
B. 7 Characteristics of Living Things 6. Reproduction • life must have ability to reproduce, no organism lives forever. • Living organisms pass on hereditary information from parents to offspring.
2 Types of Reproduction 1. Asexual Reproduction-one parent divides into 2 identical offspring- EXAMPLES • Binary fission -bacteria • Budding -sponges -fungi like yeasts • Regeneration- earthworms Advantage- don’t need mate; Disadvantage- no genetic variations 2. Sexual Reproduction-2 parents combine genetic info to form a unique individual -Egg of a female & sperm of a male form a ZYGOTE- info from both parents
Cell Reproduction: Mitosis & Meiosis There are 2 kinds of cell division in eukaryotic cells: • Mitosis occurs in cells for growth, development, repair or asexual reproduction. • Meiosis occurs during formation of gametes for sexual reproduction www.ccs.k12.in.us/.../Humanembryology.htm
Reproduction An interesting organism: Volvox • Common colonial algae • Reproduces- asexually & sexually! • Asexual- 1 parent cell simply splits into 2 identical “daughter” cells • Sexual reproduction: The dark spheres are egg -cells. They are fertilized by small packages of sperm.
Reproduction & Inheritance Some important terms: • DNA molecule- • deoxyribonucleic acid • has “how to” info • Gene- a segment on DNA macromolecule - may be 100s of genes on a DNA strand - codes for a specific trait (like eye color) • Inheritance- traits passed from parent to offspring
B. 7 Characteristics of Living Things 7. Change over Time(Evolution) • Populations of living organisms evolve or change through time. -Evolution- from “evolve” meaning to change.
II. 3 Themes in Biology • Unity of life’s Diversity -Life is diverse yet shares unity in molecules -DNA & genetic code • Interdependence of Organisms -organisms interact with biotic & abiotic factors C. Evolution- theory that organisms change over time, the driving force is the environment.
DNA The Genetic code - all life has hereditary information inDNA –DNA molecules (Deoxyribonucleic acid) -Double helix- shape is formed by nitrogenous base pairs attached to a sugar-phosphate backbone.
“Unity of Life’s Diversity” • Taxonomy: the classification of organisms • Tree of Life: shows that all living things have descended with modification from a single common ancestor
Phylogenic Tree • Shows relationships: • between 3 Domains & 6 Kingdoms
Taxonomic Classification: • 3 domains:Bacteria, Archaea, and Eukarya. • 6 Kingdoms:Archaea, Bacteria, Protista, Fungi, Plantae, and Animalia. • Further divided into smaller Taxonomic groups: • phyla • class • order • family • genus • species
3 Domains • Archaea -Prokaryotic cells (unicellular) -little understood, recently discovered life -probably oldest cells & found in extreme environments KINGDOM– Archaea • Bacteria= Prokaryotic cells (unicellular) -all the common bacteria, both good & bad -KINGDOM—Bacteria 3. Eukarya = Eukaryotic cells (have a nucleus) There are four kingdoms in Eukarya * Protista * Fungi * Plantae * Animalia
6 Kingdoms- examples Archaea, Bacteria, Protista, Fungi, Plantae, Animalia. www.ucmp.berkeley.edu www.dph.state.ct.us www.microscopy-uk.org.uk www.wetwebmedia.com usuarios.lycos.es usmo4.discoverlife.org danny.oz.au
II. 3 Themes in Biology B. Interdependence • Ecology- How organisms interact with both other organisms & the environment. • Biotic Factors – livingorganisms • Abiotic Factors- non-living part of the environment (water, temperature, soil type,etc) • Ecosystems-Communities of different living species (Biotic factors)& interact with each other & their non-living environment (Abiotic factors).
Ecology • Is the study of how organisms interact with each other and their physical environment. • Environment– everything- biotic & abiotic- surrounding an organism
In ecology we will study: • Trophic levels in the food chain • The Biosphere • Population growth, limiting factors • Species interactions: Predation, competition, parasitism, Mutualism & Commensalism • Successional changes in communities • Major Biomes of the world • Use of resources, pollution • Watershed & Wetlands
Energy Relationships-study how organisms get, use & transfer energy • Sun- Source of almost all energy • Autotrophs- Organisms that make their own energy (food) (photosynthesis) • Heterotrophs– Organisms that obtain energy by eating other organisms
Food Chain & Food web in an Antarctic Ecosystem All food chains must start with a producer (autotroph)!!! What is the difference between a food chain & a food web?
Note numbers of organisms: Chart: many times more producers than large carnivores
BIOSPHERE • the thin layer of Earth’s crust, atmosphere & ocean layers that supports LIFE • includes: • All plant and animal life • Air, soil and water. • A variety of ecosystems that As far as we know so far - we are the only life in the universe…
Are we alone? Earth Age:About 4.5 Billion Years OldLocation:In the Solar System, on the outer edge of the Milky Way, about 28,000 light years from the galactic center
Life in the Biosphere- 3 parts: • ATMOSPHERE– light blanket of air enveloping the earth, with more than half its mass within 4 miles of the surface and 98% within 16 miles • HYDROSPHERE--- the surface & subsurface waters in oceans, rivers, lakes, glaciers, groundwater • LITHOSPHERE--- upper earth's crust containing the soils that support plant life, the minerals that plants and animals require for life and the fossil fuels and ores that humans exploit.
Hydrosphere: • Surface Data: • 70% of earth is covered by water • Remaining 30% -7 continental land masses. • Water Composition: • 97% salt water, • 3% fresh water • 2% glaciers/ice • only.3% usable!
Atmosphere: • Air Composition: • 78% nitrogen, • 21% oxygen, • 1% other • Atmosphere Layers: • Trophosphere • Stratosphere • Mesosphere • Thermosphere • Exosphere
Lithosphere- Earth Layers: Inner core- solid Outer core- liquid Mantle- solid Asthenosphere- molten like playdough Lithosphere- solid • Includes the crust, is very thin • Fragmented into tectonic plates which move. • Plate movement is called plate tectonics.
Ecology Levels of Organization • ORGANISM-Simplest Level (1 living thing) • POPULATION-All the members of thesamespecies - that live in one place at a given time & make-up a breeding group. • COMMUNITY-Includes all the interacting populations in one area. • ECOSYSTEM- Includes all the living (biotic) & non-living (abiotic) factors in the environment. • BIOSPHERE- Thin layer of life around earth.
A Changing Environment • Abiotic Factors do not remain constant • Organisms able to survive a range of conditions, both natural cycles & manmade change • Most individuals can survive average conditions