Second Grade Life Science
As a branch of science, life science covers a pretty broad scope. It discusses the very basics of life and its simplest forms, looking into how very small details and units can affect an entire being. This will be seen in your child's study and observation of cells, which is why it is included in this article. Life science also discusses the complexities of organisms, finding ways to understand living things as a whole in order to find ways to better its existence or cure it from diseases.
How Cells Work
Part of understanding simple forms of life involves studying cells. To use its classic definition, cells are the basic units of life. They are the building blocks which make up living things. The structure and functions of cells are essential for life to survive. It is within the cell that living things are able to properly make use of oxygen (carbon dioxide in the case of plants) and process nutrients in order to sustain life.
There are two main types of cells that are studied in elementary school. These are the plant cells and animal cells. Apart from the obvious difference in the type of organism they make up, plant and animal cells have further differences that can help distinguish them from each other.
Animal cells come in different shapes and sizes. The biggest animal cell known to man is an Ostrich egg. This egg is a single cell which will later divide and form itself into a baby ostrich. All animal cells are able to divide themselves into two other cells in a process called mitosis. It is through this cell division that cells are able to multiply and create multicellular organisms that become larger with the growing number of cells.
You can note the characteristics of an animal cell under a microscope. Animal cells will have cell membranes (what protects the cell from harmful outside environments), a cytoplasm (little bits within the cell in which the cell's gathered nutrients are used), and the nucleus (the large rounded object in the middle of the cell which stores the cell's blueprint also known as DNA, it is through this that cells are able to divide into two identical cells.) One major characteristic of animal cells is that they need outside nourishment in order to sustain life. The cells in your body absorb water and nutrients through the circulation of your blood and in this manner are able to sustain themselves till it's time to divide and create new cells.
Unlike animal cells, plant cells have the ability to create their own food. Within each plant cells are chloroplasts or areas in which photosynthesis can take place. The chlorophyll found in chloroplasts aids in photosynthesis and is what is responsible for giving leaves their green color. Like the animal cell, however, plant cells also have a nucleus which also contains the blueprints of the plant's structure. They also have the cytoplasm in which the gathered nutrients are used. Plant cells also have cell membranes, but are further protected by a cell wall. The cell wall in plant cells surrounds the cell membrane.
In the second grade, science classes often focus on plant cells because this type of cell is easier to see under a microscope, and its different parts are also easier to spot. It's because of this simplicity that they are preferred for second graders. Though the above descriptions make plant cells seem slightly more complex, in reality there are many more parts to an animal cell that will be discussed with your child in future grades.
Next Article: Seeing Cells
