Survival through Adaptation

Getting Food

Armor and Defenses


Food and water are limited in some environments. This means that plants and animals compete with one another for the limited resources. In these ecosystems, it becomes important for plants to protect the food and water stored in their leaves, roots, and stems.

Like knights riding into battle, many plants have armor! A knight’s armor is crafted from leather and metal. A plant doesn’t have someone to make its armor. It needs to make it itself! But how? Plants have leaves, stems, and roots. Every part of a plant is made from one of these three organs. This means plants make their armor by modifying leaves, stems, and roots.

Let’s look at an example of root armor!

Cryosophila albida makes armor by modifying root tissue! Let’s look at a cross-section of a Cryosophila albida root spine next to a cross section of a delicious and common root, the carrot!

cross section of a root spine with blue dye added

Cryosophila albida root spine cross section with blue dye added | Photograph by Sean Lahmeyer

Orange circle on dusty gold background. The circle has three concentric rings of different shades.

Cross section of a carrot root

What similarities do you see? These cross-sections show the same internal anatomy but in different colors!

Now, compare the internal structure of the Cryosophila root spine with the internal structure of two other kinds of plant armor. What similarities do you see? What differences?

cross section of a root spine with blue dye added

Cryosophila albida root spine cross section with blue dye added | Photograph by Sean Lahmeyer

Green circle with twelve small blue-ish dots forming an inner ring.

Allaudia ascendens thorn | Photo by Sean Lahmeyer

Irregular circle with brown on the outside and reddish brown on the inside.

ceiba insignis prickle | Photograph by Sean Lahmeyer

Note: Some desert plants have adapted armor to protect the plant from losing too much water. The spines of a cactus create shade that cools down the plant. Cactus spines also trap the moisture that is in the air. Both of these features help desert plants conserve water. Most plants that have adapted armor have done so for a different reason. Most plants that have armor use them to protect themselves from hungry animals.

Plant Spotlights

Stronger Together

When we work together, we can all succeed. We might have different needs, but we can all get our needs met. This is the idea behind mutualism. Mutualism is a type of symbiotic relationship. Some species have evolved mutualistic relationships that they rely on for survival.

Sym means “together.” Biotic means “living.” So symbiotic means living together.

In symbiotic relationships, two or more different species live together and affect each other. Do you have a plant in your home or in your neighborhood? Your plant needs carbon dioxide. Your plant takes in carbon dioxide, turns it into oxygen, and releases that oxygen back into the air. You need oxygen! You breath in the oxygen that the plant makes. When that oxygen is in your lungs, your body turns it into carbon dioxide. When you breathe out, you release the carbon dioxide into the air. Who needs carbon dioxide? Your plant! You and your plant take care of each other. You are in a symbiotic relationship with the plants around you.

plant growing on a tree trunk. The plant's light green roots cling to the trunk. The plant's leaves are a light green.

Plants may compete or co-exist with other plants. Epiphytes are plants that grow up in trees, where they can get more light without harming the trees. Some plants can be harmful because they wrap around other species and strangle them slowly over time.

Some plants and animals have developed mutualistic relationships for survival. Check out Myrmecodia tuberosa to learn about a mutualistic relationship between a rainforest plant and a species of ants!