Scientia Academy Checkpoint Science (Grade 6) Biology 4. Living Things In Their Environment Habitats: A habitat is the place where an organism or a community of organisms lives. A habitat includes all living and non-living factors or conditions of the surrounding environment. Almost every place on Earth—from the hottest desert to the coldest ice pack—is a habitat for some kinds of living things. Every organism has its own habitat and they adapt accordingly. This is where the organism meets its basic need for its survival: food, water, shelter from the weather and place to breed its younglings. Habitat can be terrestrial (land) or aquatic. Terrestrial habitat includes forests, grasslands, deserts, coastal and mountain regions. The aquatic habitat includes freshwater habitats (lakes, ponds, rivers and streams, wetlands, swamp, etc) and marine habitats (oceans, intertidal zone, reefs, seabed, etc.). There are different types of Habitats. Rainforests habitat: These are lush, warm, wet habitats. Trees in the rainforest grow very tall because they have to compete with other plants for sunlight. Kapok trees, which are found in tropical rainforests around the world, can grow to 200 feet. Plants: Orchid, vine, moss, and fern. Animals: Bat, gorilla, monkey, sloth, macaw, and variety of insects. Freshwater habitat: Rivers, lakes, ponds, and streams are examples of freshwater habitat. Fish, frog, duck, lotus, and water lily are found in fresh water, Marine water habitat: Oceans and seas form the largest habitat on the planet. Some commonly found animals are whale, dolphins, sharks, octopus, starfish, jellyfish, seahorse, etc, and plants, seaweeds are the most common. Dessert Habitat: Deserts are areas that receive very little rainfall less than 25 cm annually. In hot desert, daytime temperature in summer can reach 45 degree Celsius. Organisms such as cactus, camel, gila monster and kangaroo rat are found here. Polar Habitat: Polar and mountainous regions are the coldest of all the habitats found on earth. These include the Arctic and the Antarctic regions. In the Antarctic, the lowest temperature recorded was -88 Degree Celsius. Animals such as polar bear, penguin, seal and walrus are found in Polar Regions. Aquatic Habitat : Streamlined body helps to swim Grassland Habitat Scientia Academy Checkpoint Science (Grade 6) Biology Polar Habitat Forest Habitat Adaptation: Adaptation is how a species changes its body and behaviour to better suit its natural environment. Plants and animals adapt themselves to exist in very cold as well as hot climate. The natural environment is an ever-changing feature of planet earth. The organisms need to adapt themselves to these changes to survive; the organisms which cannot adapt die out. . Thus process of adaptation ensures that the species which adapts the most, survive. Different kinds of organisms are present in different habitats as they adapt to different abiotic changes in different ways. 1. Plants present in desert lose very little water through transpiration. They are adapted to this by having small leaves or spine shaped leaves and sometimes even the leaves are absent. They also have thick wax coated stem, and roots are long to go very deep in to the soil. 2. Different plants and animals found in mountains are adapted to the cold and windy climate and even from snowfall in different ways. Trees have cone shaped sloping branches with needle like leaves so that rainwater and snow can slide off easily. Animals have thick skin or fur or hair to protect them from cold. For example yak, snow leopard. The mountain goat is an animal has strong hooves for running up the rocky slopes of the mountains. 3. Prey and predators found in grasslands adapt several features to survive. For example, i) a lion and ii)a deer. A lion is a prey wants to eat animals have long claws in the front legs , light brown colour, eyes in front of the face which allows it to hunt animals and kill its prey. 4. Fishes have streamlined bodies to move easily inside water. Other sea animals which do not have streamlined body stay very deep inside the ocean and when they move in water they make their body streamlined. Some animals have gills to use dissolved oxygen. Some animals like dolphin breathe air through blowholes located on the upper parts of their head. Dolphins can stay inside water without breathing for a long time and when needed come out to the surface to breathe in air. 5. The aquatic plants have roots fixed in the soil and only hold plants in place. Stems are long, hollow, light and grow above the surface of water and leaves, flowers, float on the surface of water. Some aquatic plants are found to be totally submerged in water and these have highly divided leaves for the flow of water without damaging them. Frogs are found both in water and land. Their strong back legs help them in catching prey and webbed feet to swim in water. Scientia Academy Checkpoint Science (Grade 6) Biology Desert Habitat: Thorns to prevent water loss Food chains and food webs: Food chains and webs describe the transfer of energy within an ecosystem, from one organism to another. Food chains and food webs are diagrams that represent feeding relationships. A food chain is a series of organisms that eat one another so that energy and nutrients flow from one to the next. A food chain represents a single pathway by which energy and matter flow through an ecosystem. Food chains are generally simpler than what really happens in nature. Aquatic Food Chain Terrestrial Food Chain A food web represents multiple pathways through which energy and matter flow through an ecosystem. Sometimes, a single organism gets eaten by many predators or it eats many other organisms. This is when a food chain doesn’t represent the energy flow in a proper manner because there are many trophic levels that interconnect. The diagram then used is called Food Web. It includes many intersecting food chains. It demonstrates that most organisms eat, and are eaten, by more than one species. Scientia Academy Checkpoint Science (Grade 6) Biology Energy Pyramid: An Energy Pyramid is a diagram that shows the flow of energy from one trophic level to the next in an ecosystem. This diagram compares the energy used by organisms at each trophic level. The structure of an energy pyramid reflects the trophic structure of an ecosystem. The pyramid is divided into trophic levels similar to those in a food chain. Energy pyramids can be represented as pyramid of biomass or pyramid of numbers. Pyramid of biomass represents the amount of biomass at each trophic level in an ecosystem. The population of species in a food chain is shown using a Pyramid of numbers. Organisms in an ecosystem affect each other’s population. The trophic level of an organism is the position it occupies in a food web. At the base of the food chain lie the primary producers. The primary producers are autotrophs and are most often photosynthetic organisms such as plants, algae etc. Producers use energy from sunlight to make their own food. A food chain always starts with a producer. The organisms that eat the primary producers are called primary consumers. Primary consumers are usually herbivores, plant-eaters, though they may be algae eaters or bacteria eaters. Scientia Academy Checkpoint Science (Grade 6) Biology The organisms that eat the primary consumers are called secondary consumers. Secondary consumers are generally meat-eaters—carnivores. The organisms that eat the secondary consumers are called tertiary consumers. These are carnivore-eating carnivores, like eagles or big fish. Some food chains have additional levels, such as quaternary consumers—carnivores that eat tertiary consumers. Decomposers are organisms that carry out decomposition (break down) of dead or decaying organisms. Fungi, bacteria, worms and insects acts as decomposers in nature. The shape of an energy pyramid shows that the amount of food energy that enters each trophic level is less than the amount that entered the level below. Approximately 90 percent of the food energy that enters a trophic level is “lost” as heat when it is used by organisms to power the normal activities of life such as breathing and digesting food; the remaining 10 percent is stored in the various organisms’ tissues. It is this latter energy that is available to be passed to the next trophic level. Thus, the higher the trophic level on the pyramid, the lower the amount of available energy. The number of organisms at each level decreases relative to the level below because there is less energy available to support those organisms. The top level of an energy pyramid has the fewest organisms because it has the least amount of energy. Eventually there is not enough energy left to support another trophic level; thus most ecosystems only have four trophic levels. Some examples of food chain explained below: 1. An earthworm breaks down dead organic matter in the soil which the plants, sitting one level up in the pyramid, utilize to manufacture their food along with the light from the sun during the photosynthesis process. The herbivores in the next level up in the pyramid, in turn, use the stored energy in the plants by feeding on the plants. The energy contained in the fecal matter from the herbivores is recycled back into the system where it is broken down further by the earthworms. 2. Mice on the forest floor eat the seeds and fruits of trees, shrubs, and flowers for energy. The eagle, sitting at the next level up the energy pyramid eats the mice, taking in the energy they have stored. It is worth noting that adult eagles have no natural predators. That means they occupy the topmost level of their energy pyramid. 3. Grasshoppers eat grass for their energy. The grasshoppers, in turn, give their energy to frogs in the next level up the pyramid, which feed on them. Snakes in the next level of the pyramid get their energy from frogs and so on.
