Tropism Stations - Adv

Tropisms Stations

Biology :)

Station 3

Station 2

Station 1

Light

Touch

Gravity

If your station has a microscope, do not move it!!

Station 4

Station 5

Station 6

Anatomy of Leaves

Anatomy of a stem

REVIEW!!

Gravity - Geotropism

Imagine a plant growing in a pot. Even if you turn the pot upside down, the plant will still grow with its roots going down and its leaves reaching up towards the sunlight. How does the plant know which way is up or down? Geotropism (or Gravitropism) is the answer. It's a plant's ability to grow in response to gravity. Gravity is ALWAYS pushing down. Roots: They grow downward, towards the center of the Earth. This is called positive geotropism because it moves WITH the stimulus of gravity. It helps them find water and nutrients in the soil. Stems: They grow upward, away from the Earth's center. This is called negative geotropism because it moves AWAY from the stimulus of gravity. It helps them reach sunlight for photosynthesis.

Here's another one: Hydrotropism

Hydrate - Hydrotropism

Why would a plant need to look for water? Well, plants in the wild are not as lucky as house plants - they must FIND their water sources. How does that work? Hydrotropism! It's a plant roots' ability to grow in response to water sources... as if the roots can "smell" water. Roots: They grow toward the source of water. This is called positive hydrotropism because it moves WITH the stimulus of water.

Touch - Thigmotropism

In the picture, you can see a vine climbing a tree. It doesn't have eyes to see the tree, but it can still wrap around it and climb higher. How does it know to do this? Thigmotropism: It's a plant's ability to respond to touch or contact with objects. Climbing plants: When a vine touches a solid object, it tends to grow in a curved way that wraps around it. This helps the plant climb higher and reach more sunlight. Venus flytraps: These carnivorous plants have sensitive hairs on their leaves. When an insect touches these hairs, the leaves snap shut, trapping the insect inside. This is a specialized form of thigmotropism that helps the plant catch its food.

Light - Phototropism

Have you ever noticed a plant's bend towards a light source? Watch the video!! How does it know to do this? Phototropism: It's a plant's ability to grow or move in response to light. Plants towards light: When a plant is exposed to light from one side, the side facing the light tends to bend more towards the light than the side facing away from the light. This helps the plant get more sunlight for photosynthesis. We can see this in the stem and leaves. Plants away from light: Some plants, like those that grow in the shade, may exhibit negative phototropism. This means they grow away from light. This helps them avoid excessive light that could damage them, for example roots. Roots exhibit negative phototropism because too much light can dry out the roots, essentially limiting the plant's ability to absorb water.

Stems: Monocot VS Dicot

ONLY FILL IN WHAT THE CHART ON YOUR NOTES HAS!

Flowers have sepals that are in groups of 4 or 5

Monocot flowers have sepals / petals in threes

Leaves are simple, singular and have parallell veins

Stem is complex, but show a ring in the outer edge

Stems are simple with vascular bundles scattered

Leaves are simple or compound with non-parallell veins

Can you identify stems in the slides?

Roots are 'fibrous' and can form bulbs (tulips)

Root is complex; usually a woody taproot

Stomata

Leaf Anatomy

Stomata: Tiny pores on plant leaves that facilitate gas exchange. Gas exchange: Plants take in carbon dioxide for photosynthesis and release oxygen and water vapor. Guard cells: Specialized cells that control stoma opening and closing. - Water balance: Guard cells regulate stomata to balance water loss and gas exchange.

Leaves are adapted for photosynthesis. The outer coverings, often waxy looking (epidermis) protect the leaf. Vascular bundles (xylem and phloem), that look similar to veins, transport materials throughout the leaf. Other Important structures are listed in the boxes to your right. Can you see the chloroplasts/vascular bundles in the slides?

Chloroplasts

Chloroplasts are the organelles responsible for photosynthesis in plant cells. They contain chlorophyll, a green pigment that absorbs sunlight. Chloroplasts: Convert light energy into chemical energy (glucose) through photosynthesis. Chlorophyll: Absorbs sunlight, providing the energy needed for photosynthesis.