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Chapter 1: The Science of Life. Biology – The study of life Organism – A living thing; anything that can carry out life processes independently Branches.

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Presentation on theme: "Chapter 1: The Science of Life. Biology – The study of life Organism – A living thing; anything that can carry out life processes independently Branches."— Presentation transcript:

1 Chapter 1: The Science of Life

2 Biology – The study of life Organism – A living thing; anything that can carry out life processes independently Branches of biology – There are many subtopics within biology – a few examples we’ll hit upon this year:

3 Biochemistry – Study of the chemistry of life Genetics – Study of how organisms pass traits to their offspring  Evolutionary theory – Study of changes in types of organisms over time  Cell biology – Study of life on the cellular level  Microbiology – Study of microscopic organisms  Botany – Study of plants  Zoology – Study of animals  Physiology – Functions, activities, and processes of organisms  Ecology – Study of how organisms interact with eachother and the environment

4 Properties of Life 1. Cellular organization  Cell – a highly organized, tiny structure that in enclosed in a thin covering called a membrane  A cell is the smallest unit capable of all life functions

5 Organisms can be unicellular or multicellular Multicellular organisms – more than 1 cell Cells in these organisms are considered specialized (have certain jobs) Examples: some fungus, all plants, all animals

6  Unicellular organisms - one cell 1 cell does all jobs for organism Examples: bacteria, protists, and some fungus

7 There are various levels of cellular organization –vary based on how complex the organism is  In general: cells  tissues  organs  organ systems  organisms  Cells are the smallest unit of life, organisms the biggest


9 2. Homeostasis Maintaining a stable internal environment in order to function properly (such as body temperature, pH, blood pressure, water balance) regardless of changes in the external environment  Example: sweating or shivering to maintain body temperature

10 3. Metabolism – the sum of all of the chemical reactions carried out in an organism Reactions carried out to obtain energy Organisms can obtain energy in one of two ways: heterotrophs and autotrophs

11 Heterotrophs are organisms that obtain nutrients from food eaten Ex: some bacteria and protists, fungus, & animals Autotrophs are organisms that make their own food through photosynthesis Ex: plants, some protists, and some bacteria

12 4. Responsiveness – living organisms must respond to their external environment Ex: plants bend toward the light, birds fluff feathers to stay warm in winter

13 5. Reproduction – the process by which organisms make more of their own kind from one generation to the next  Prevents extinction of species  Can be sexual or asexual 6. Heredity – process through which an organism passes on its own traits to its offspring during reproduction

14 Asexual reproduction only 1 parent offspring has DNA identical to parent Sexual reproduction 2 parents each parent contributes ½ genetic information to offspring offspring has mixed traits from parents

15 7. Growth - an increase in the number of cells/ increase in the size  Example – getting taller  As organisms grow, they may change, or develop  Development – Changes an organism undergoes to reach adult form  Example – baby  kid  teen  adult; tadpole to frog; caterpillar to butterfly

16 Classification Taxonomy – The practice of naming and classifying organisms Taxa –the categories into which organisms are classified

17 The taxa: Domain Kingdom Phylum (Division for plants) Class Order Family Genus Species Did King Phillip Came Over For Good Spaghetti???


19 Domain Archaea –  Unicellular prokaryotes  May have been first cells  Live in aquatic environments that lack oxygen or are too salty, too hot, or too acidic for most other organisms – like primitive Earth(?)

20 Domain Bacteria  Unicellular prokaryotes  Found almost anywhere – in soil, water, atmosphere, on and inside living organisms

21 Domain Eukarya  Cells contain membrane-bound nucleus  Four Kingdoms within –  Protists (Protista)  Fungus (Fungi)  Plants (Plantae)  Animals (Animalia)


23 Why can’t we just use common names? Not very specific Ex: What KIND of frog? Misleading Ex: Jellyfish is NOT a fish, ringworm is NOT a worm Vary by language and geography Ex: Puma, mountain lion, and cougar are ALL the same animal! A robin in one country is not the same as what is named a robin in another country

24 What was wrong with the early systems of classification? Forgot to include bacteria, fungus and protists Failed to show proper relationships between organisms Too general – ex. Aristotle classified animals by where they lived (air, land, or water)

25 Modern system of classification:  Based in part on Carl Linnaeus’ system of binomial nomenclature (“two names”)  Grouped according to:  physical features (morphology)  the ancestral relationships between species (phylogeny)

26 Those placed in the same genus will be most closely related, those in different kingdoms most distantly related Ex: Those in genus Felis are more closely related to each other than organisms in the Kingdoms Plantae and Animalia are to each other.

27 Writing scientific names: Ex: Homo sapiens or Homo sapiens Can be abbreviated H. sapiens  If typed – should be italicized.  If handwritten – should be underlined.  First word is genus – capitalized  Second word is species - lower case

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