Loading...
NestJS
Quiz by Enzo Billis
Customize this quiz to suit your class
Instantly translate to 100+ languages
Tag the questions with any skills you have. Your dashboard will track each student's mastery of each skill.
Give this quiz to my class
NextJSPlacement NextJSCity Animals Mice live in cities. They eat food people throw away. Geese and ducks live in cities. They swim in ponds in parks. Squirrels live in cities. Squirrels make nests in trees. Pigeons live in cities. Some people like to feed pigeons. Opossums live in cities. They like to come out at night. Hawks live in cities. They make nests on tall buildings. Dogs live in cities. People bring them to the park. Raccoons live in cities. They take food from trash bins. Do you see animals where you live? What kinds of animals do you see?Eagles and Eaglets Bald eagles are birds. The baby birds, or offspring are called eaglets. Let's read about how eaglets are like their parents. It's Nesting Time. All birds lay eggs. Bald eagles build their nests in the tops of trees so the eggs will be safe. Their nests are built of sticks and grass. They add on to their nests each year. They can become huge! These giant nests can be as large as nine feet across. That's bigger than your bed! The mother eagle lays from one to three eggs. She sits on her eggs until they hatch. Then both parents watch over the nest. Proud Parents. At first the eaglets are helpless. They cannot walk. They need their parents for food. They also cannot see well. Birds are not mammals. They do not have milk to feed their young. They hunt for food. Eaglets also need their parents for safety. Eaglets Grow Up. Bald eagles use their sharp eyes to hunt. They use their strong wings to fly fast. They also use their claws and beak to catch fish. Young eaglets must learn all these things. Then they can live on their own. Unlike mammals, birds have feathers, not fur. An eaglet is born covered with soft gray down. It cannot fly until it grows dark feathers like its parents. The eaglet stays near the nest until its wings grow strong. That takes about five months. An eaglet becomes an adult when it has learned to do all the things its parents do. This takes about five years. Bald eagles can stay alive for up to thirty years.Bald Eagles Soar. Once it learns to fly, the bald eagle can soar for hours. The bald eagle must take good care of its feathers. It uses its beak to groom itself. It must keep its feathers clean. Can you believe this powerful eagle began life as a helpless baby?Camera traps Technology is being used more and more in film and photography, For example, wildlife photographers sometimes use camera traps. When a photographer uses a camera frap the camera is hidden; for example, in a tree or on the ground so the animals cannot see it. When an animal moves near the camera, the camera is furned on and it takes a photo or a short film. Sometimes the camera is fixed onto an animal so it can take a film as the animal moves. The film then helps us to leam much more about the animal's life. Photo engineers of National Geographic design camera traps to help photographers hide cameras, for example in birds nests or on the ocean floor. They've designed camera traps for National Geographic photographers like Steve Winter, who takes photos of wild animals such as tigers, leopards, jaguars and bears. The camera trops are set up so that the animal looks straight into the camera. Steve thinks that if people see good photos of wild animals, they'll understand more about the animals and want to protect them. Photo engineers have to design cameras that will not break when they're being used in places like jungles or the ocean. Sometimes photographers use small remote-controlled cars to carry cameras. Technology is improving all of the time and helping photographers to take amazing photos. Thanks to the technology of camera traps, we can all see the world in new and interesting ways.đŁ What are oviparous animals? Oviparous animals are animals that are born from eggs. This means the baby does not grow inside the motherâs body, but instead grows inside an egg that the mother lays. đ„ How does this process work? The mother lays one or more eggs. Inside the egg, the baby (called an embryo) begins to grow. The egg protects the baby and gives it food to grow. After some time, when the baby is ready, it breaks the eggshell and comes out. đ Examples of oviparous animals: Birds (like chickens, penguins, and parrots) Reptiles (like turtles, crocodiles, and snakes) Fish, amphibians, and insects also lay eggs. đŠ What about dinosaurs? Dinosaurs were oviparous too! The dinosaur moms laid eggs in nests. Inside each egg, a baby dinosaur grew safely. When the baby was ready, it broke the shell with its head or a special part of its mouth and came out. Some were born alone, and others hatched with many brothers and sistersâjust like a dinosaur family!Figure 18-11 represents the amount of energy stored as organic material in each trophic level in an ecosystem. The pyramid shape of the diagram indicates the low percentage of energy transfer from one level to the next. On average, 10 percent of the total energy consumed in one trophic level is incor- porated into the organisms in the next. Why is the percentage of energy transfer so low? One reason is that some of the organisms in a trophic level escape being eaten. They eventually die and become food for decomposers, but the energy contained in their bodies does not pass to a higher trophic level. Even when an organism is eaten, some of the molecules in its body will be in a form that the consumer cannot break down and use. For example, a cougar cannot extract energy from the antlers, hooves, and hair of a deer. Also, the energy used by prey for cellu- lar respiration cannot be used by predators to synthesize new bio- mass. Finally, no transformation or transfer of energy is 100 percent efficient. Every time energy is transformed, such as during the reactions of metabolism, some energy is lost as heat. Limitations of Trophic Levels The low rate of energy transfer between trophic levels explains why ecosystems rarely contain more than a few trophic levels. Because only about 10 percent of the energy available at one trophic level is transferred to the next trophic level, there is not enough energy in the top trophic level to support more levels. Organisms at the lowest trophic level are usually much more abundant than organisms at the highest level. In Africa, for exam- ple, you will see about 1,000 zebras, gazelles, and other herbivores for every lion or leopard you see, and there are far more grasses and shrubs than there are herbivores. Higher trophic levels con- tain less energy, so, they can support fewer individuals.A population is a group of organisms that belong to the same species and live in a particular place at the same time. All of the bass living in a pond during a certain period of time make up a pop- ulation because they are isolated in the pond and do not interact with bass living in other ponds. The boundaries of a population may be imposed by a feature of the environment, such as a lake shore, or they can be arbitrarily chosen to simplify a study of the population. The humans shown in Figure 19-1 are part of the pop- ulation of a city. The properties of populations differ from those of individuals. An individual may be born, it may reproduce, or it may die. A population study focuses on a population as a wholeâhow many individuals are born, how many die, and so on. Population Size A populationâs size is the number of individuals that the population contains. Size is a fundamental and important population property but can be difficult to measure directly. If a population is small and composed of immobile organisms, such as plants, its size can be determined simply by counting individuals. Often, though, individ- uals are too abundant, too widespread, or too mobile to be counted easily, and scientists must estimate the number of individuals in the population. Suppose that a scientist wants to know how many oak trees live in a 10 km2 patch of forest. Instead of searching the entire patch of forest and counting all the oak trees, the scientist could count the trees in a smaller section of the forest, such as a 1 km2 area. The scientist could then use this value to estimate the population of the larger area. SECTION 1 OBJECTIVES â Describe the main properties that scientists measure when they study populations. â Compare the three general patterns of population dispersion. â Identify the measurements used to describe changing populations. â Compare the three general types of survivorship curves. VOCABULARY population population density dispersion birth rate death rate life expectancy age structure survivorship curve FIGURE 19-1 A population can be widely distributed, as Earthâs human population is, or confined to a small area, as species of fish in a lake are. Copyright © by Holt, Rinehart and Winston. All rights reserved. 382 CHAPTER 19 If the small patch contains 25 oaks, an area 10 times larger would likely contain 10 times as many oak trees. A similar kind of sampling technique might be used to estimate the size of the pop- ulation shown in Figure 19-2. To use this kind of estimate, the sci- entist must assume that the distribution of individuals in the entire population is the same as that in the sampled group. Estimates of population size are based on many such assumptions, so all esti- mates have the potential for error. Population Density Population density measures how crowded a population is. This measurement is always expressed as the number of individuals per unit of area or volume. For example, the population density of humans in the United States is about 30 people per square kilome- ter. Table 19-1 shows the population sizes and densities of humans in several countries in 2003. These estimates are calculated for the total land area. Some areas of a country may be sparsely popu- lated, while other areas are very densely populated. Dispersion A third population property is dispersion (di-SPUHR-zhuhn). Dispersion is the spatial distribution of individuals within the popu- lation. In a clumped distribution, individuals are clustered together. In a uniform distribution, individuals are separated by a fairly con- sistent distance. In a random distribution, each individualâs location is independent of the locations of other individuals in the popula- tion. Figure 19-3 illustrates the three possible patterns of dispersion. Clumped distributions often occur when resources such as food or living space are clumped. Clumped distributions may also occur because of a speciesâ social behavior, such as when animals gather into herds or flocks. Uniform distributions may result from social behavior in which individuals within the same habitat stay as far away from each other as possible. For example, a bird may locate its nest so as to maximize the distance from the nests of other birds. These migrating wildebeests in East Africa are too numerous and mobile to be counted. Scientists must use sampling methods at several locations to monitor changes in the population size of the animals. FIGURE 19-2 TABLE 19-1 Population Size and Density of Some Countries Population size Population density Country (in millions) (in individuals/km2) China 1,289 135 India 1,069 325 United States 292 30 Russia 146 8 Japan 128 337 Mexico 105 54 Kenya 32 54 Australia 20 3 dispersion from the Latin dis-, meaning âout,â and spargere, meaning âto scatterâ Word Roots and Origins Copyright © by Holt, Rinehart and Winston. All rights reserved. POPULATIONS 383 The social interactions of birds called gannets, which are shown in Figure 19-3b, result in a uniform distribution. Each gannet chooses a small nesting area on the coast and defends it from other gannets. In this way, each gannet tries to maximize its distance from all of its neighbors, which causes a uniform distribution of individuals. Few populations are truly randomly dispersed. Rather, they show degrees of clumping or uniformity. The dispersion pattern of a population sometimes depends on the scale at which the popu- lation is observed. The gannets shown in Figure 19-3b are uni- formly distributed on a scale of a few meters. However, if the entire island on which the gannets live is observed, the distribution appears clumped because the birds live only near the shore. POPULATION DYNAMICS All populations are dynamicâthey change in size and composition over time. To understand these changes, scientists must know more than the populationâs size, density, and dispersion. One important measure is the birth rate, the number of births occur- ring in a period of time. In the United States, for example, there are about 4 million births per year. A second important measure is the death rate, or mortality rate, which is the number of deaths in a110.31.b.17.C