Biological pigment

Living things have colors.

These colors come from tiny things called pigments.

Plants use green pigments to catch sunlight. This helps them make food.

Some plants have other colors too. Red or yellow pigments show in flowers. These colors help bugs find them.

Animals use color to stay safe. Some animals use colors to hide. Others use bright colors to talk to each other.

In the fall, leaves change color. The green parts go away. This shows the hidden red and yellow colors.

Colors are everywhere in our world.

Living things have many colors. These colors come from substances called pigments.

Pigments work by soaking up certain colors of light. They reflect other colors back to our eyes.

Plants use pigments to make food. The most important one is chlorophyll. This is a green pigment. It helps plants catch light energy.

When leaves change in the fall, chlorophyll breaks down. This lets other colors show. You might see yellow or orange. These are called carotenoids.

Flowers also use pigments. Some have anthocyanins, which are pigments that look red or blue.

These colors help bugs find flowers for food.

Animals use pigments in many ways. Some use them for camouflage to hide. Others use bright colors to talk to other animals.

Some animals have melanin. This is a pigment in skin and hair. It can help protect skin from the sun. Some animals cannot make their own pigments. They must get them from the food they eat.

Biological pigments are special substances made by living things. They give color to plants, animals, and even tiny bacteria. These colors happen because of a way called selective absorption. This means a pigment soaks up some colors of light but reflects others. The colors that bounce off are what our eyes see.

Some colors come from pigments, while others come from structure. Structural color happens when light hits layers in things like butterfly wings. Unlike pigments, structural color can change depending on the angle you look from.

In the plant world, pigments have a very important job. Most plants use a green pigment called chlorophyll to perform photosynthesis. This is the way plants turn light into energy to grow.

Chlorophyll absorbs blue and red light but reflects green light. Other pigments like carotenoids help catch even more light energy. They also protect the plant from getting damaged by too much light. Some plants also use pigments like anthocyanins to color their flowers. These bright colors help pollinators like bees find nectar and pollen.

Plants also show us pigments when the seasons change. In the autumn, the green chlorophyll in many leaves begins to break down. As the green fades, other pigments that were already there become visible. You might see yellow xanthophylls or orange beta-carotene in the leaves. Some plants also make new red pigments called anthocyanins during this time. This is why many trees turn beautiful shades of red and purple in the fall.

Animals use pigments for many different reasons too. Some animals use them for camouflage to hide from others. Others use bright colors to signal to mates or warn enemies.

A common pigment in animals is melanin, which is found in skin and hair. Melanin can help protect tissues from the sun's ultraviolet radiation. Some animals, like certain insects, can even make their own carotenoids. Most marine animals cannot make these pigments and must eat plants to get them.

Sometimes, pigments can be linked to health conditions. Albinism is a condition where a person or animal has a loss of melanin. This can be a total or partial loss of pigment. Another condition is vitiligo, where pigment-producing cells are lost in patches of skin. Some people also experience melasma, which creates dark brown patches on the face. These things happen when there is too much or too little pigment produced by the body.

Biological pigments, also known as biochromes, are substances produced by living organisms. These molecules create color through a process called selective color absorption. When light hits a pigment, the substance absorbs specific wavelengths of light. The wavelengths that are not absorbed are reflected back to our eyes. This allows us to see different colors in the natural world.

It is important to distinguish pigments from structural color. Pigments produce the same color regardless of the viewing angle. In contrast, structural color results from selective reflection or iridescence. This often happens because of complex multilayer structures, such as those found in butterfly wings.

In the plant kingdom, pigments serve vital biological functions. The primary role of most pigments is to assist in photosynthesis. This is the process where organisms convert light energy into chemical energy. Chlorophyll is the most important pigment for this task. It is a chlorin that absorbs blue and red wavelengths of light. Because it reflects most green light, plants appear green to us.

Different organisms use different types of chlorophyll. For example, all land plants and green algae use chlorophyll a and b. However, red algae possess only chlorophyll a. Kelps and diatoms use chlorophyll c instead of chlorophyll b.

Plants also utilize accessory pigments to maximize their energy intake. Carotenoids are a group of red, orange, or yellow tetraterpenoids. These molecules help with light-harvesting and provide photoprotection. Photoprotection allows the plant to dissipate energy and prevent damage from light. Carotenoids also serve as structural elements for proteins. Within this group, there are several specific types. Lutein is the most abundant carotenoid in plants. Lycopene is the red pigment found in tomatoes. Other examples include alpha carotene in carrots and lactucaxanthin in lettuce.

Other plant pigments include anthocyanins and betalains. Anthocyanins are water-soluble flavonoid pigments. They can appear red or blue depending on the pH level of the plant tissue. These are often highly visible in flower petals. Betalains are also water-soluble but are synthesized from tyrosine. These pigments are found only in the order Caryophyllales, which includes cacti. They are responsible for the deep red color in beets.

Interestingly, betalains and anthocyanins never co-occur in the same plant.

Seasonal changes in deciduous trees provide a clear look at pigment shifts. During autumn, the green chlorophyll begins to degrade. As chlorophyll breaks down, it turns into colorless substances called nonfluorescent chlorophyll catabolites. This degradation reveals pigments that were already present, such as yellow xanthophylls and orange beta-carotene. Additionally, some plants synthesize new red anthocyanins once half of the chlorophyll has degraded. The amino acids released during this process are stored in the tree's roots and branches. They are recycled the following spring to grow new leaves.

Animals use pigmentation for survival and communication. Many species use pigments for camouflage to hide from predators. Others use mimicry or warning coloration to signal to other animals. Some animals, such as cephalopods, use specialized cells called chromatophores to communicate.

In humans and other animals, melanin is a common pigment in skin and hair. Melanin helps protect tissues from damage caused by ultraviolet radiation from the sun. Some pigments, like the heme groups that carry oxygen in blood, are colored by happenstance. They do not serve a specific signaling or protective function.

Marine life also relies heavily on pigment chemistry. Most marine animals cannot synthesize their own carotenoids. Instead, they must consume plants to obtain these pigments. Many marine invertebrates use carotenoproteins for mating rituals and camouflage. There are two main types: Type A and Type B. Type A involves carotenoids associated with a simple glycoprotein. Type B involves carotenoids associated with a lipoprotein and is usually less stable. These complexes can create a wide range of colors, including blue, red, and green.

Sometimes, biological systems experience issues with pigment production. Albinism is an inherited disorder involving the total or partial loss of melanin. In humans and animals, this results in a lack of pigment. Other conditions involve the excess production of pigment. Lamellar ichthyosis, or "fish scale disease," causes the skin to be darker than normal with scaly patches. Melasma causes dark brown patches to appear on the face, often influenced by hormones. Vitiligo occurs when pigment-producing cells, called melanocytes, are lost in patches of skin.