Mouse and a Lion | Quizalize

All animals, most protists, all fungi, and many bacteria are het- erotrophs. Unlike autotrophs, heterotrophs cannot manufacture their own food. Instead, they get energy by eating other organisms or organic wastes. Ecologically speaking, heterotrophs are consumers. They obtain energy by consuming organic molecules made by other organisms. Consumers can be grouped according to the type of food they eat. Herbivores eat producers. An antelope that eats grass is a herbivore. Carnivores eat other consumers. Lions, cobras, and praying mantises are examples of carnivores. Omnivores eat both producers and consumers. The grizzly bear, whose diet ranges from berries to salmon, is an omnivore. Detritivores (dee-TRIET-uh-VAWRZ) are consumers that feed on the “garbage” of an ecosystem. This waste, or detritus, includes organisms that have recently died, fallen leaves, and animal wastes. The vulture shown in Figure 18-8 is a detritivore. Many bacteria and fungi are detritivores that cause decay by breaking down complex molecules into simpler molecules. So, they are specifically called decomposers. Some of the molecules released during decay are absorbed by the decomposers, and some are returned to the soil or water. Decomposers make the nutrients that were contained in detritus available again to the autotrophs in the ecosystem. Thus, the process of decomposition recycles chemical nutrients. Copyright © by Holt, Rinehart and Winston. All rights reserved. 368 CHAPTER 18 ENERGY FLOW When one organism eats another, molecules are metabolized and energy is transferred. As a result, energy flows through an ecosystem, moving from producers to consumers. One way to follow the pattern of energy flow is to group organisms in an ecosystem based on how they obtain energy. An organism’s trophic (TRAHF-ik) level indicates the organism’s position in a sequence of energy transfers. For exam- ple, all producers belong to the first trophic level. Herbivores belong to the second trophic level, and the predators belong to the third level. Most terrestrial ecosystems have only three or four trophic lev- els, whereas marine ecosystems often have more. Food Chains and Food Webs A food chain is a single pathway of feeding relationships among organisms in an ecosystem that results in energy transfer. A food chain may begin with grass, which is a primary producer. The chain may continue with a consumer of grass seeds—a meadow mouse. Next, a carnivorous snake may kill and eat the mouse. A hawk then may eat the snake, as shown in Figure 18-9. The feeding relationships in an ecosystem are usually too com- plex to be represented by a single food chain. Many consumers eat more than one type of food. In addition, more than one species of consumer may feed on the same organism. Many food chains inter- link, and a diagram of the feeding relationships among all the organisms in an ecosystem would resemble a web, as shown in Figure 18-10. For this reason, the interrelated food chains in an ecosystem are called a food web.

Whose Tracks Are These? Animal Visitors. How do we know whether an animal has visited a place? One way we know is because it may leave tracks, or marks in the soil. Tracks show where the animal's body has touched the ground. Let's find out who has visited us today! Large Animals. A large animal that likes honey made these tracks. This animal is a good climber. It has strong claws for digging up plants, and it eats animals, too. Can you guess who it is? A black bear made these tracks. Black bears sleep all winter and wake up hungry in the spring. A large animal with hooves made these tracks. This animal can eat ten pounds of leaves, bark, and twigs each day. Can you guess who it is? A deer made these tracks. Male deer grow antlers in the spring and shed them in late winter. Baby deer have spots that disappear when they grow up. A large, strong cat made these tracks. This hunter runs fast and jumps far. It eats other animals, such as deer. birds, and rabbits. Can you guess who it is? A mountain lion made these tracks. Adult mountain lions live alone most of the time. Babies must learn to hunt before they can leave their mothers. Small Animals. A smart bird made these tracks. It has a curved beak and sharp claws. It hunts at night and eats many kinds of animals. Can you guess who it is? An owl made these tracks. It has large yellow eyes and can see well in the dark. It makes a noise called a hoot. A small animal made these tracks. Its tail made the line between the footprints. This animal must run very fast to escape being eaten. Can you guess who it is? A mouse made these tracks. Mice are food for owls, snakes, and other animals. But this one got away! Many Kinds of Tracks. Each kind of animal has its own special tracks. Look for tracks when you are in nature. Have fun finding out who has been visiting!

The lion and the mouse

Parts of a computer only monitor, mouse and keyboard

Let's Make Shapes! A line connects two points. A line is longer than it is wide. Lines can be short, and lines can be long. Lines can be straight, and lines can be curved. You can bend lines to make a shape. You can join straight lines together to make a shape. You can join curved lines together to make a shape. There are many kinds of shapes. Circles, squares, rectangles, and triangles are geometric shapes. We can use geometric shapes to draw many things. When a line goes all the way around, it makes a circle. You can use a circle, three small circles, and a curved line to make a face. On another piece of paper, draw a circle. Then make it a mouse with eyes, ears, and whiskers. Use lines and more circles. If we cut a circle in half, we get two half-circles. You can use four half-circles to draw a caterpillar. On another piece of Then make it into a fish paper, draw a half-circle. with eyes, a tail, and fins. When a line turns a corner three times, it makes a triangle. Triangles have three sides and three corners. You can use triangles to make a face on a pumpkin. On another piece of paper, Then make it into a tree draw a triangle. with leaves and a trunk. When a line turns a corner four times, it makes a square. A square has four sides and four corners. Each side is the same length. You can use squares and half-circles to make a truck. On another piece of paper, draw a square. Then make it into a dog by adding ears, a tail, and legs. Use curved lines and straight lines. A rectangle has four sides, just like a square. Two sides are the same length. The other two sides are another length. You can use rectangles, circles, squares and lines to draw a bus. On another piece of paper, draw a rectangle. Then make it a house with a roof, two windows, and a door. Use a triangle and three rectangles. Now, on another piece of paper, make a picture using all of the shapes: circles, squares, triangles, and rectangles.

Dia for María Ratona was a cat named Mouse. She was small and gray, and had a tiny squeaky meow. She liked to sit in a hole in the shed wall. Ratona lived for a long time. Eight months ago, she died. I'm not sad anymore, but I think about her often. One day, Mamá was setting up Tía Teresa's ofrenda, a special altar, for Day of the Dead. Teresa passed away when I was a baby. "Mamá, can we celebrate pets?" I asked. "This is mostly for family, though I suppose Ratona was part of ours," Mamá said. "We can celebrate her the day before," I suggested. Later, Mamá and I went to the market in Puebla. We got paper banners, sugar skulls, and marigolds. On October 31, my friends came over. Adriana brought her dog, Sal. or Salt. She had a photo of Sal's sister, Pimienta, or Pepper, who died last summer. Gloria had a picture of Raúl the rooster, a pet she had lost. We set up the banners, marigolds. and photos where Ratona used to sit. "Once, Pimienta stole a pound of cheese from our cooler. She got into the trash and ate it later! I have cheese for Pimienta," Adriana said. "My mother makes pumpkin seeds for my great-grandfather's ofrenda. Raúl jumped up and ate them! My mother was so mad. I brought some for Raúl," Gloria said. "If someone had ice cream, Ratona went Squeak! Squeak! until you let her lick the bowl. I have ice cream for Ratona," I said. I gave Adriana and Gloria sugar skulls before they left. I thought about funny little Ratona. On the last day of celebrations, my family walked to the graveyard. Everyone from the area came. There were fireworks and even a band. Tía Teresa's gravestone was piled with flowers, sweet bread, and candles. Mamá smiled to herself. "One day, María, your Tía Teresa heard a tiny squeak coming from the grass. It was a little gray kitten. Teresa named her Ratona," Mamá said. She continued, "When Teresa died, I took Ratona. You loved her right away. You reminded me of Teresa." Everyone was laughing and dancing. I was too young to remember Tía Teresa, but we had both loved Ratona. That made me happy. Mamá took my hand. "I think it's time to dance!" she said.

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