1 Study of copyright cmassengale Edited by pdunning EHS Characteristics of Life

2 What is Biology? Biology is the study of all living things Living things are called organisms Living things are called organisms Organisms include bacteria, protists, fungi, plants, & animals

3 All Living Things Share Common Characteristics 1. Basic Unit is the Cell 2. They Reproduce 3. All Based On Universal Genetic Code (DNA) 4. Grow & Develop

4 Common Characteristics 5. Obtain & Use Materials & Energy 6. Respond To Their Environment 7. Maintain A Stable Internal Environment 8. AS A GROUP, Living Things Evolve, That Is They Change Over Time

5 Characteristics of Organisms

6 All Organisms are made of Cells

Cell Structure and Function Cell basic unit of life All organisms are made of and develop from cells Some composed of only a single cell (unicellular) which is usually identical to parent

8 Facts About Cells Cells are the smallest living unit of an organism All cells contain cytoplasm All cells are surrounded by a cell membrane that controls what enters & leaves the cell

9 More Cell Facts Cells are complex & highly organized Cells have parts called organelles that do different jobs e.g. Chloroplasts in plants make sugars e.g. Chloroplasts in plants make sugars

10 More Cell Facts The simplest cells are called Prokaryotes These cells DO NOT have a nucleus or membrane-bound organelles Bacteria are examples

11 More Cell Facts More complex cells are called Eukaryotes These cells DO have a nucleus and membrane- bound organelles Plants, animals, protists, & fungi are examples

12 Organisms are Grouped by their Number of Cells Unicellular Organisms Unicellular Organisms –Living Organism Made Up Of One Cell Multicellular Organisms Multicellular Organisms –Living Organism Made Up Of Many, Specialized Cells

13 Cells All living things are composed of cells In multicellular organisms, many are specialized to perform specific functions Cells are always very small The size of multi-celled organisms depends on the number of cells NOT their size Copyright Cmassengale

Living things reproduce Copyright Cmassengale 14

15 Organisms Reproduce to Pass on their Genetic Traits

16 Reproduction All species have the ability to reproduce All species have the ability to reproduce Not essential to survival of individual but is essential for continuation of a species Not essential to survival of individual but is essential for continuation of a species Copyright Cmassengale

17 Two Types of Reproduction Sexual Reproduction Involves 2 parents Egg fertilized by sperm to make a ZYGOTE Offspring DIFFERENT from parents

18 Two Types of Reproduction Asexual Reproduction Involves a single organism or cell Cell divides Offspring IDENTICAL to parent

19 Cells Have a Genetic Code copyright cmassengale

20 Genetic Code DNA (deoxyribose nucleic acid) carries the genetic code for all organisms All organisms contain DNA DNA codes for the proteins that make up cells & do all the work necessary for life

21 Organisms Grow & Develop

22 Growth & Development Organisms grow by producing MORE CELLS & by cell ENLARGEMENT Organisms develop as they mature into an adult organism

23 Growth Grow occurs as the result of cell division and cell enlargement Cell division is the formation of two cells from a preexisting cell New cells enlarge as they mature When a cell grows to a size where its surface area isn’t big enough for its volume, the cell divides Copyright Cmassengale

24 Cells Require Food & Energy

25 Food Requirements Autotrophs can make their own food Photoautotrophs use sunlight to make food (photosynthesis) Chemoautotrophs use chemicals such as iron & sulfur as their energy

26 Food Requirements Heterotrophs can NOT make their own food They must consume other organisms Herbivores eat plants Carnivores eat meat Omnivores eat plants & animals

27 All organisms need substances such as nutrients, water, and gases from the environment All organisms need substances such as nutrients, water, and gases from the environment The stability of the environment depends on the healthy functioning of organisms in that environment

28 Metabolism Sum of all the chemical reactions in an organism All require energy Sunlight is the ultimate energy for life on Earth

29 Metabolism Cellular Respiration –Cells releasing the chemical energy stored in foods 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O

30 Organisms Respond to Stimuli Organisms Respond to stimuli (Temperature, Water, Food Supplies, etc.) In Order To Survive & Reproduce

31 Homeostasis Keeping The Internal Environment (Homeostasis) Of The Cell or Organism Within The Ranges Required For Life Stable internal conditions of pH, temperature, water balance, etc.

32 Living Things Evolve Groups Of Organisms (Not Individuals) Change Over Time In Order To Survive Within Changing Environments. Fossil records show changes in groups of organisms

33 Explains why organisms look and behave the way they do Provides a basis for exploring the relationships among different groups of organisms

34 Natural Selection Natural selection is the driving force in evolution Organisms that have certain favorable traits are better able to successfully reproduce than organisms that lack these traits

35 Natural Selection Survival of organisms with favorable traits cause a gradual change in populations over many generations Copyright Cmassengale

36 Life is Organized on Several Levels

37 Levels AtomsMoleculesOrganelles Cells – life starts here TissuesOrgansSystemOrganism

38 Levels PopulationCommunityEcosystemBiosphere

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