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Chapter 1: The Scope of Biology. Honors Biology. How Can We Organize the Planet?. Biosphere Ecosystem Organism Cell DNA Gene . The Biosphere.
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Chapter 1: The Scope of Biology Honors Biology
How Can We Organize the Planet? • Biosphere Ecosystem Organism Cell DNA Gene
The Biosphere • Biosphere – all of the parts of the planet that are inhabited by living things • Sum of all Earth’s ecosystems • Includes air, land, surface rocks, and water
Ecosystems • Ecosystem – community of living things plus the nonliving features of the environment that supports them
Organisms • Organism – a living thing • Interactions between organisms within an ecosystem make it a constantly changing place Sea Sponge Mushroom/Tree Symbiosis E.coli bacteria
Cells • Cell – basic unit of living matter • Separated from environment by plasma membrane • Life’s basic unit of structure and function • How big is a cell??? • Mouse cells (~10 microns in diameter)
DNA • Deoxyribonucleic acid (DNA) – molecule responsible for inheritance • Nucleic acid containing the sugar deoxyribose
Genes • Gene – unit of inherited information in DNA • Found along the length of DNA
Section 1.2 Biology Explores Life in its Diverse Forms
Life’s Diversity of Species • Species – distinct form of life • More than 1.5 million species known today • 5,000 bacteria • 8,600 birds • 30,000 fish • 100,000 fungi • 280,000 plants • 1,000,000 insects
Classifying Species • Classification – organizing similar species into larger groups • Domain – broadest category used to classify life forms • Archaea • Bacteria • Eukarya
Domain Archaea and Bacteria • Mostly unicellular • Entire bodies consist of single cell • Prokaryotic – cells with no nuclei • DNA is not separated from rest of cell
Domain Eukarya • Made up of organisms characterized by eukaryotic cells • Contain nuclei and other organelles • Multicellular • Organisms made up of many cells • Can be further divided into 4 kingdoms • Kingdom Protista • Kingdom Fungi • Kingdom Plantae • Kingdom Animalia
Section 1.3 Ten Themes Unify the Study of Life
Some basic ideas apply to biology at all levels and for all organisms Biological Systems The Cellular Basis of Life Form and Function Reproduction and Inheritance Interaction with the Environment Energy and Life Regulation Adaptation and Evolution Biology and Society Scientific Inquiry Themes in Biology
Biological Systems • System – complex organization formed from a simpler combination of parts • “The whole is greater than the sum of its parts” • An ecosystem as an example • Properties depend on how parts interact
The Cellular Basis of Life • All organisms are made up of cells • In most multicellular organisms, cells are organized into higher levels of organization • Tissues – group of cells working together to perform specific function
Form and Function • Form fits function • Occurs on all levels
Reproduction and Inheritance • Living organisms have the ability to reproduce their own kind • Inheritance based on genes made up of DNA • In humans, egg cell from mother fuses with sperm cell from father, resulting in a fertilized cell containing a combination of DNA from both parents
Interaction with the Environment • All organisms are part of an ecosystem, interacting continually with their environments • Transfer of chemicals between organisms and their environments is key process in any ecosystem • Photosynthesis – process by which plants use the sun’s energy to convert water and carbon dioxide into sugars • Organisms also constantly sense and respond to changes in the environment
Energy and Life • All organisms must perform work, which requires a source of energy • Ecosystem’s organisms convert energy from one form to another • Producers – plants and other photosynthetic organisms that produce the food upon which the entire ecosystem depends • Consumers – animals and other organisms that eat food made by producers • All organisms lose energy in the form of heat, meaning that ecosystems cannot recycle energy • Life depends on continuous supply of energy from sun
Regulation • Organisms must have the ability to regulate their internal environment • Homeostasis – mechanisms enabling organisms to regulate their internal environment despite changes in their external environment
Adaptation • Individuals in all populations vary • Population – localized group of organisms belonging to the same species • Adaptation – inherited trait that helps an organism’s ability to survive and reproduce in a particular environment • If a particular variation is helpful, individuals with the variation may live longer and produce more offspring than those who do not have it, a process called natural selection
Evolution • Natural selection is mechanism by which evolution occurs • A generation-to-generation change in the proportion of different inherited genes in a population
Biology and Society • Science affects everyday life • New developments in technology • New discoveries
Scientific Inquiry • Biology is a science, and all sciences rely on inquiry • Involves asking questions about nature and the using observations or experiments to find possible answers to those questions