Plant Growth Investigation

For the end of the year, we are investigating the germination and growth of peas. Our first task was to identify the factors that affect germination and growth, and how we can control these factors:

Our next task will be to plan a Fair Test to see what happens if we change one of these factors on purpose.

Biodiversity

Today, we learned that there is often variation within a population. This helps the population (but not all of the individuals) survive if factors change. For example, a new predator may arrive in the habitat. But is this biodiversity always a good thing?

When conditions change, this biodiversity can lead to Natural Selection:

Osmosis

Today, we started to look at the process of osmosis. Sadly, the wet weather meant we could not do our experiment outside, so we will do it tomorrow.

Osmosis helps explain how water gets absorbed by the roots of plants. This is the first step in the water getting to the leaves.

In our experiment, we found that the potato chip in the saline solution became really bendy (flaccid). We think this is because water was lost from the potato into the saline solution it was soaking in. The potato chip in the tap water became really hard (turgid). We think this is because the potato absorbed some tap water. These are both examples of osmosis in action.

Transpiration

Leaves are water-proof, so how does the water required for photosynthesis get into the leaves of a plant?

We saw that the food colouring had gone into the leaves, and that there was a smaller volume of water in the beaker. When we cut the celery stem, we saw coloured tubes in the stem. These are called xylem tissue, and help get the water up the stem to the leaves.

Plants - Leaves

We started by looking at the main parts of a flowering plant:

http://www.cactus-art.biz/note-book/Dictionary/aaa_Dictionary_pictures/flowering_plant.jpg

Then, we focused on the leaves of plants:

Here is a website that talks about photosynthesis: http://www.biology4kids.com/files/plants_photosynthesis.html

Microscopes

We learnt about the parts of microscopes and how to use them to look at slides. On Tuesday, we will get a chance to make our own slides and to look at them under a microscope.

Animal Cells

Today, we looked at the structure of animals cells, then compared and contrasted animals with plants: