Chapter 1
Earth Science
Course: Elementary Education Multiple Subjects 5001
Subject: Elementary Education Science Subtest 5005
Chapter: Life Science
1. Growth and Development
Growth is the process by which organisms increase in size or number of cells. This often involves cell division (mitosis), where one cell divides to produce two identical cells. Growth can also include the accumulation of body mass or the elongation of structures like roots or limbs.
Development refers to all the changes that occur as an organism matures. These changes may include structural transformations, changes in behavior, or shifts in function.
In animals:
- Growth begins after fertilization when a single-celled zygote begins dividing to form an embryo.
- As the organism grows, cells differentiate and specialize into types like nerve cells, muscle cells, and skin cells.
- Organs and organ systems develop and become functional over time.
In plants:
- Growth is concentrated in the meristems, located at the tips of roots and shoots.
- These regions are where cells divide rapidly and later specialize into plant tissues like xylem, phloem, or leaf tissue.
- Environmental conditions such as sunlight, water, and nutrients influence the rate of growth.