Life Science 8 th Grade Week 1 Mrs. Rubright

- Characteristics of Living Things - Concept of spontaneous generation - Characteristics of Living Things - The Needs of Living Things - Basic needs of a living thing - Flow of energy from the sun through food chains - Water is essential to all living things - The Chemistry of Living Things - Relationship of compounds and molecules to the needs of living things - Organic compounds needed by most living things

Asexual reproduction – reproduction that involves only one parent and in which the offspring is identical to the parent Stimulus – anything that affects the activity of an organism Spontaneous generation – the theory that living things can develop from nonliving matter Sexual reproduction – reproduction that involves two parents and in which the offspring have characteristics of both parents Metabolism – the sum of chemical activities taking place inside a living cell or organism Homeostasis – the ability to maintain a stable internal environment

Can something Living really come from something Non-Living? Francesco Redi Disproved the theory of Spontaneous Generation in the 17 th century – No, flies don’t simply sprout from rotting meat Why would anyone accept the theory of Spontaneous Generation?

Spontaneous Generation debunked! Louis Pasteur – won a prize for debunking the theory once and for all in 1864 Pasteur found Microorganisms are carried through the air and onto other substances where they begin to grow Pasteur proclaimed, “Never will the doctrine of spontaneous generation recover from the mortal blow of this simple experiment.” Why would some scientists still accept the theory of Spontaneous Generation?

All living things: 1. are made of cells, the building blocks of life Cells “Build” living things and perform the life functions required to thrive 2. reproduce, and reproduce after their own kind One way that God maintains balance through sexual or asexual reproduction: Gorillas always reproduce gorillas; Hollyhocks always reproduce hollyhocks. 3. grow and develop in size and/or complexity A newly conceived mammal is made up of two cells, which divide and develop into a baby ready to be born 4. respond to their environment The activity of an organism is called a stimulus and the response can be an action, movement, or behavior change 5. use energy Complex chemical activities that make up an organisms metabolism assist in making and breaking down food, moving materials in and out of cells, and building cells Only a living thing has all 5 characteristics Crystals grow, yet are not living things. Why not?

Habitat – the place in which an organism lives

All living things need: 1. food Different living things need different chemicals and energy, so they eat foods that contain the chemicals and energy they need 2. water You could live for a week without food, but only about 3 days without water. Blood, which is mostly water, dissolves minerals and nutrients to carry throughout the body; sap, which is mostly water, dissolves sugars and nutrients to carry throughout a tree. Without water metabolism couldn’t happen 3. energy Organisms use energy in different ways; a mushroom uses energy to grow; a bird uses energy to build a nest; a tree uses energy to produce leaves. The source of all of these examples of energy is the sun. 4. certain gases When organism use oxygen during respiration, they exhale carbon dioxide back into water or air. Plants use this carbon dioxide for photosynthesis and then release oxygen back into the air - a recycling plan that continues to provide Earth with oxygen and carbon dioxide 5. space (not outer space- that’s a different class) or habitat All organisms need enough space to thrive, but the amount of space needed differs greatly. Many microorganisms can live in a drop of water the size of a grain of sand, but a pair of jaguars requires almost 1000 acres of rainforest to thrive. Ever wonder why trees in a forest seem to grow a certain distance apart?

God uses photosynthesizing plants as the bridge between the sun and the rest of the organisms that he sustains in the biosphere If you trace the energy used by any pant or animal back as far as you can, you will discover that the sun is the source of energy for all of these things

Element – a pure substance that cannot be broken down into simpler substances by physical or chemical means Compound – a pure substance consisting of atoms of two or more elements that are chemically combined in a fixed proportion Organic compound – a compound that contains carbon Molecule – a particle consisting of two or more atoms chemically tied together Atoms of individual elements Oxygen Hydrogen Compound consists of chemically linked elements Water (H2O) Molecules can be elements or compounds Water Molecules Oxygen Molecules Compounds can be organic or inorganic. Living things contain over 3 million organic compounds

Enzymes – special proteins that speed up chemical reactions in an organism or cell Carbohydrates – organic compounds made from one or more sugar molecules Proteins – organic compounds made of amino acids Nucleic acids – organic compounds that contain genetic information and the information necessary for an organism to make the protein it needs Lipids – organic compounds that are fats and oils Complex Carb – many sugar molecules Simple Carb – one or few sugar molecules Proteins make up muscles, antlers and feathers, build and repair cells, and carry materials through the body Lipids provide and store energy and make up most of a cell’s membrane

What is Life? What is Death? How are living things related to each other? How are other living things different from us?