The Characteristics of Living Things

Notes

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Six Characteristics of ALL Living Things :

  1. Made of cells
  2. Need energy
  3. Grow and develop
  4. Respond to the environment
  5. Reproduce
  6. Adaptations for their environment

1) All living things have Cells.  The cell is the basic unit of life.

  • All organisms are made up of at least 1 cell 
  • Usually microscopic in size, trillions of microscopic cells in trees or in us!

2) All living things need Energy!

  • Energy is the ability to make things move or change
  • Organisms get energy from the environment:
    • Plants = Sun
    • Animals = Surrounding environment

 

Nutrients:

Substances that provide the energy (fat, protein, carbohydrates) and materials (minerals, vitamins) that organisms need to grow, develop, and reproduce

Metabolism: 

The sum of all the different processes that happen inside an organism 

  • Energy is converted inside the cell for us to use, the energy amount has to be balanced:
    • Too much energy conversion = obesity
    • Too little energy conversion = malnutrition
WHITE BLOOD CELL DOING ITS THING!

WHITE BLOOD CELL DOING ITS THING!

3) All living things Respond to the Environment!

Stimulus:

Anything that causes a response in an organism

Response:

An organism’s reaction to a stimulus

4) Grow and Develop

  • Bigger and change of structure
  • Changing of body shape

5)  Reproduce

  • All living things come from other living things
  • Reproduction does not mean an individual organism will survive, but the survival of the species

6) Adapt to their Environment

Adaptation:

Physical or behavioural characteristic of a species that increases the species’ chances of survival in a particular environment


Structure And Function

All Organisms need to do certain things to stay alive

  • Ex. Hunt for food, exchange gases & nutrients
  • As such, organisms have developed different ways of doing these tasks

Structure:

Parts of an organism that perform specific tasks to survive

Function:

Purpose or task

    Different Structures for Similar Functions

    • But different plants and animals have developed different structures for doing similar functions
    • Example: Using light to respond to the environment
      • Human – Camera eye
      • Insects – Compound eye
      • Amoeba – Phototaxis

     Organs & Organ Systems

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    Organs:

    Group of tissues that work together to perform a specific function

    Organ system:

    Group of organs that work together to perform a certain task

     

    Different Types of Organ Systems in Us:

    • Circulatory system
    • Respiratory System
    • Nervous system
    • Excretory System
    • Digestive System
    • Skeletal System
    • Muscular System
    • Integument System

    The Microscope

    Without a microscope our eyesight can only see clear, defined images of things that are 0.1 mm or larger

    • This means we cannot see any microorganisms that could make us sick!
    • Created a lot of myths

    Example Fig. 2.3 (p. 99)

    RENAISSANCE MAN... GREAT HAIR TOO.

    RENAISSANCE MAN... GREAT HAIR TOO.

    Micro-organisms first discovered by Anton Van Leeuwenhoek.

    • Used lenses to look at blood samples
    • He made an object appear larger than it’s actual size…termed magnified.
    • Robert Hooke was looking at cork
      • Fig. 2.1 for his microscope
      • Coined the term ‘cells’

    Today’s Microscopes:

    • 2 General Types Used in Science Research
      • Compound Light Microscope (up to 2000 X magnification)
      • Electron Microscope (up to 2, 000, 000 X magnification)
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    Magnification :

    • Ocular lens (usually 10x)  X  Magnification Lens (4x, 10x, or 40x)

    Field of View :

    The entire area you can see when you look through the microscope. 

    Diameter of Field:

    The diameter of the field of view, it's the distance between one side of the lens to another. Diameter of field depends on magnification!!

    Lets say at 10x magnification (AKA ocular lens only) your diameter of field is 20mm:

    At Low power the objective lens is 4x magnification. So the diameter of field is 4 times smaller :

    Diameter of Field / Objective lens magnification

    20mm / 4 = 5mm

    At Medium power the objective lens is 10x magnification. So the diameter of field is 10 times smaller :

    Diameter of Field / Objective lens magnification 

    20mm / 10 = 2mm

    At High power the objective lens is 40x magnification. So the diameter of field is 40 times smaller :

    Diameter of Field / Objective lens magnification 

    20mm / 40 = 0.5mm



    The Cell Is the Basic Unit of Life

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    The Cell Theory

    • All living things are composed of one or more cells
    • Cells are the basic units of structure & function in all organisms
    • Cells with similar structure & function are organized into tissues
    • Tissues work together for a common purpose to form organs
    • A group of organs that work together for a common purpose to keep you alive is called an organ system!

    Cell Size & Function

    • Cells need a constant supply of materials like oxygen, water, nutrients
    • Also needs to get rid of waste products
    • All these materials going in/out of cell pass through the cell membrane (to be discussed)
    • Generally, most cells fall into a small range of size (10-50 um)

    Looking at Cells

    There are certain factors that can affect what you are able to see in the amount of detail when looking inside a microscope:

    • Type of microscope
    • Power of the lens
    • Quality of the prepared slides

    Cell Structures

    A HUMAN CELL

    A HUMAN CELL

    Organelles:

    Inside the cell, there are structures that have particular functions to keep the cell alive

    • Some organelles may be found in both plants and animals
    • Some may only be found in plant cells
    • Some may only be found in animal cells
    • Why the variety of organelles? Depends on the purpose of the cell (Ex. Muscle cell vs. leaf cell)

     Organelles

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    Nucleus:

    The command center of the cell

    • Control’s the cells activities
    • Holds the cell's DNA
    • Directs all cellular activities such as movement, growth, and other life functions
    • In both plants and animal cells

    Mitochondria:

    The powerhouse of the cell

    • Chemical reactions occur that convert energy into useable forms
    • In both plant cells & animal cells

    Cell membrane:

    Controllable gateway in and out of the cell

    • Surrounds & protects the contents of the cell
    • Looks like a thick line around the cell
    • Lets needed materials in & waste materials out
    • In both plant cells & animal cells

    Vacuoles:

    The storage room of the cell

    • Membrane bound sac acting as a storage space for excess food & wastes
    • Clear, liquid filled space in cytoplasm
    • Plants generally have 1 big vacuole, animal cells generally have many small vacuoles

    Cytoplasm:

    The Kitchen of the cell

    • Covers everything inside the cell except the nucleus
    • Contains nutrients required by the cell
    • Distributes material to different parts of the cell
    • Found in both plant cells & animal cells

    STRUCTURES ONLY FOUND IN PLANT CELLS

    PLANT CELL

    PLANT CELL

    Cell Wall:

    The frame of the cell

    • Found in Plant cells NOT in animal cells
    • A rigid frame-like covering that surrounds the cell membrane
    • Provides support for the cell   

    Chloroplasts:

    The solar panels of the cell

    • Structures in which photosynthesis takes place
    • Greenish structures found only in plant cells

     

    • Pg 103 – list of cell structures and features that can help you identify them.
    • Pg 106 – directions for preparing a wet mount.
    • Pg 107 – directions for preparing and viewing a cell specimen
    • Pg 108 – the structures of a cell and their functions.
    • Pg 109 – Animal and plant cell labelled diagrams.

    Organisms Can Be Single-Celled or Multi-celled

    Remember!  Cells are the individual living units that make up all living organisms.

    ROTIFERS ARE THE SMALLEST KNOWN MULTICELLULAR ORGANISM

    ROTIFERS ARE THE SMALLEST KNOWN MULTICELLULAR ORGANISM

    Multicellular:

    Made of  2 or more cells

    Unicellular:

    Made of just one cell

    Micro-organisms :

    Very small, generally unicellular organisms that can be seen only through a microscope

    • Unicellular organisms :developed specialized structures to perform functions such as eating, moving, reproducing, excreting and reacting to stimuli. (Bacteria, amoebas, paramecium) 
    • Multi-cellular organisms: rely on many very specialized cells to perform functions such as to eat, to move, to reproduce, all the cells interact with one another. (
      • Ex. To eat: cells for digestion, cells for absorption, cells for carrying nutrients throughout body, cells for the muscle to move

    Amoeba

    • Lives in water, Moves around using pseudopodia
    • Foot-like projections. ‘False feet’
    • A pseudopod is extended and the cytoplasm fills it. Moves very slow
    • Also uses the pseudopodia to eat by surrounding their food (algae, bacteria, plant cells) to create a vacuole

    Paramecium

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    • Moves very fast in the fresh water, covered in cilia to move
    • Hair like structures that move back & forth
    • Cilia also used to capture food (algae) by channeling food to an oral groove
    • Forms a food vacuole to be digested

    How Substances Move Into & Out of Cells

    DIFFUSION OF PARTICLES MOVE FROM AN AREA OF HIGH CONCENTRATION TO LOW

    DIFFUSION OF PARTICLES MOVE FROM AN AREA OF HIGH CONCENTRATION TO LOW

    Diffusion:

    Movement of particles of a substance from an area of higher concentration to an area of lower concentration

    • It’s a balancing out process of the particles where No energy required

     

     

     

    Osmosis:

    • Special kind of diffusion
    • Diffusion of water through a selectively permeable membrane
    • Water particles are small enough to diffuse through the cell membrane with ease, depending on the concentration gradient (H to L)
    • Osmosis is vital to the survival and health of cells
    WATER MOVES FROM AN AREA OF LOW CONCENTRATION TO HIGH

    WATER MOVES FROM AN AREA OF LOW CONCENTRATION TO HIGH

    Selectively permeable:

    A membrane with very small openings that allow particles of some substances, but not others, to pass through. (Based on size)

    • A permeable membrane allows all materials to go in & out
    • An impermeable membrane does not allow anything in or out.

    Diffusion & the Cell Membrane

    Particles of many substances move in & out of cells by diffusion

    • However, the cell membrane acts like a filter with its tiny openings, allowing some particles to go through if they are small enough (I.e. semi-permeable!)

    Three Types of Water Solutions

    Isotonic solution:

    Equal concentration of solutes on each side of semi-permeable membrane

    Hypertonic Solution:

    • Solution with high concentration of solutes (very concentrated)
    • Water leaves the cell, and it shrivels
    • Potentially fatal

    Hypotonic Solution:

    Solution with the lower concentration of solutes

    • Water enters the cell, and the cell swells
    • Potentially fatal
    • Cells need an optimal amount of water concentration.  There needs to be a balance inside & outside of the cell.  If too much water enters and/or leaves the cell, the cell may die

    Cells in Multicellular Organisms

    Cells Combine to Form Tissues and Organs

    • Cells reproduce in multicellular organisms generally through mitosis & meiosis

    • In unicellular organisms generally through binary division

    Specialized cells:

    Cells that have specific structures that help them to perform particular functions

    • Specialization means that the cells of a multicellular organism must work together to support their own lives, as well as the life of the whole individual.

    For example:

    • Red blood cells are small, pliable cells that have no nucleus and are specialized for carrying oxygen to all the cells of the body.
    • Do NOT reproduce the same way as other cells
    • How do RBC’s reproduce?
    • Bones in the skeletal system have marrow which produces red blood cells.

    Animal Tissue

    All cells in humans and animals  can be categorized in four different tissue types:

    1. Nervous tissue

    2. Muscle tissue

    3. Connective tissue

    • Blood, fat, tendon, bone, cartilage
    • Supports and connect

    4. Epithelial tissue

    • ‘blanket’ which covers the surface of the body and outside organs

    Each organ is made up of different combinations of these 4 types of tissue.


    Tissue in Plants

    Plant cells are also organized into tissues, but plants have 3 tissue types:

    1) Photosynthetic/storage

    • Example: Inside of a leaf

    2) Protective

    • Example: Outside portion of a leaf that is the waterproof layer

    3) Transport- transportation of nutrients

    • Vascular tissues- connect roots to the leaves
      • Phloem tissue- specifically allows sugar to travel to the rest of the plant from leaves
      • Xylem tissue- specifically allows water to travel to the rest of plant from the roots

    Organs in Plants

    • These tissues are organized into the 3 organs that make up plants:
    1. Leaves
    2. Roots
    3. Stems

     

    Leaves are the plant’s food-producing organs

    • Where photosynthesis takes place
    • Contains chloroplasts which are thin, allowing a large amount of light in
    • Contains stomata which are tiny opening that allow air to enter the leaf
    • Spaces between leaf cells allow the air to flow and the guard cells open and close the stomata

    Transpiration:

    The loss of water in a plant which happens through evaporation

    • Not a problem unless the plant loses too much water and doesn’t replace it by the roots
    • Movement of water throughout the plant happens because of the differences in pressure - high pressure in the root hairs to lower pressure in the leaves

    Root system contains fine ‘root hairs’

    • If the soil water concentration is greater than root water concentration, water will flow inside of the root hairs, this is done by osmosis!
    • Water travels from cell to cell until it reaches the xylem tissue
    • The xylem cells move the water up the plant by a build up of high water pressure (NOT OSMOSIS!) forcing water up the xylem tissues into stems and leafs