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What is growth?
The irreversible increase in dry mass of an organism
Why is dry mass a more reliable indicator of growth?
As the water content in an organism can vary
Where does growth (cell division) take place in animals?
All over the body
In plants, growth and development starts in specific regions called...?
What is a meristem?
A group of undifferentiated plant cells capable of repeated division
What are the two types of meristems and what type of growth are they involved in?
- Apical - primary growth
- Lateral - secondary growth
Where is an apical meristem found?
At the tip (apex) of a root and shoot
Put these in the correct order:
DNA replication, mitosis and cell division
- 1. DNA replication, mitosis and cell division
- 2. Elongation
- 3. Differentiation
What is secondary growth?
When the plant increases in girth
What lateral meristem is secondary xylem made by?
How old is this tree?
- 3 years old
- (Do not count first or last ring!)
In spring, what happens to the cambium activity and the shape of the annual rings?
- Cambium activity is most active in spring
- This produces large diameter, thin walled xylem vessels to allow increased flow of water and minerals for growth as buds break dormancy and new leaves grow
In Summer, what happens to the cambium activity and the shape of the annual rings?
- Cambium is less active in summer
- Small diameter, thick walled xylem vessels produced to provide greater support and water to the additional leaves which grow on new twigs
In winter, what happens to the cambium activity?
Cambium is inactive in winter
Wider rings are produce by what kind of weather?
Warm and wet
Narrower rings are produced by...?
Cold conditions, dry conditions and leaf loss