SUMMARY # 3 (Food Chain and Food Web)

In this summary we will how do living things depend on each other for energy.

How Do Populations Interact?
Changes in one population can affect several other populations in the same ecosystem. Every population needs energy in order to survive. The energy in an ecosystem comes from the Sun. You can feel the Sun´s energy as it warms your skin. The energy of the Sun is stored in food. The energy in  the food is passed from one organism to another in a food chain. A food chain is the path energy takes from producers to consumers to decomposers. The first organism in a food chain are plants, because they capture the Sun´s energy during photosynthesis. This energy is stored in the foods the plant makes for itself.

How Do Food Chains Become Food Webs?
Plants compete for sunlight, water, and minerals. Animals compete for the plants and animals they eat. This competition means that, in an ecosystem, many small food chains may overlap each other. A food web is the overlapping foodchains. A food chain shows one population that eats or is eaten by another population. A food web shows how one populationa can be part of more than one food chain. It shows how each population in a community relates to all the other populations.

• Producers: Food chains and food webs exist in all ecosystem, They all have producers. The producers include grasses, trees, and all other organisms that use the Sun's energy to make their own food.
• Eating Producers or Consumers: Organisms that cannot make their own food are consumers. Consumers get energy fron the food made by other organisms. Consumers can be grouped according to the type of food they eat. Hervibores eat producers.
• Eating Hervibores: Hervibores are eaten by carnivores animals that eat other animals. All cats, big and small, are carnivores. Dogs, wolves, foxes, coyotes and other animasl are carnivores. The most frightening of these is the great white shark.

What is a Predator?
Are living things that hunt other living things for food. The hunted are called prey. The relationships between predators and prey are a key part of both food chains and food webs.
Not all meat eaters are predators. Some animals eat meatbut don´t hunt it. Such meat eaters are called scavengers. The feed on the remains of dead animals.
When an animal eat plant and animals it is an omnivore. We are omnivore. Bears are omnivores too.
Every food chain and food web ends with decomposers such as worms, insects, bacteria and fungi. These organisms break down dead matter into substances that can be used by producers.

What Happens When Niches Overlap?
No two populations can have the same niche. Why is this true? To have the same niche, two populationswould have to eat the same space and reproduce in the same ways. They would have to thrive under the same temoerature, moisture and light conditions. They would have to get the same diseases and look and have exactly alike. That is, they would have to be identical. Yet no two populations are identical. This does not means that similar populations with different niches do not compete. They do. When two species are very similar, teir niches overlap. Sometimes the competition causes a population to change its niche. This is specially true when a very similar population invades the habitat of anither population.

How Did The Anoles Deal With Competition?
At one time green anoles could be spotted all over Florida, perched on the trunks of trees and the branches of bushes. They were adapted to this environment for a number of reasons. Their green color camouflaged them when they were among leaves. Their ability to turn brown did the same when they clung to tree trunks. This made them hard for predators to find.
Then a new and bigger species of anole arrived in Florida fromm the island of Cuba. Soon the smaller green anole seemed to disappear, replaced by the Cuban anole.

How Is Energy Moved In A Community?
Plants capture energy from sunlight.  All organisms need energy to live. Producers get energy from the Sun. Consumers get it from the foods they eat. However, energy is losts as it passes from one organisms to another in a food chain.
An energy pyramid shows a number of things. It shows that there is less food at the top of the pyramid than as itsbase. It also shows that there are fewer organisms as you move from bottom to top.
Consumers get their energy from food. The less food ther is, the less energy is available. Energy decreases from the base to the top of the pyramid. 

What Happens When There Is A Red Tide?
Ocean Blooms on the increase off Texas Coast might not seem like a frightening headline, it means a trouble.
The blooms refer to a sudden rapid increase in the population of microscopic sea organisms called dinoflagellates. These tiny algae are producers atthe bottom of the ocean food chain. They are a part of every ocean food web. 
They are also at the base of the ocean energy pyramid. They store the Sun´s energy, whuch is passed up the pyramid. ne dinoflagellate that does this belongs to a group of algae called fire algae. They get their name mainly because of their red color. When they bloom they can turn hundreds of square miles of ocean red. That´s why a bloom of these organisms is called red tide.
People are also affectedby red tides. A person who eats poisoned shellfish can become very sick. The poisons produced by fire algae seem to only affect the nervous system of complex animals like fish, mammals, and birds.

                                                                            Food Web