+ Food Chains and Food Webs Ms. McCray 6 th Grade Science April 24 & 25

+ Standards We Will Address 6.L.2.1 Summarize how energy derived from the sun is used by plants to produce sugars (photosynthesis) and is transferred within a food chain or food web (terrestrial and aquatic) from producers to consumers to decomposers. 6.L.2.2 Explain how plants respond to external stimuli (including dormancy and forms of tropism) to enhance survival in an environment. 6.L.2.3 Summarize how the abiotic factors (such as temperature, water, sunlight, and soil quality) of biomes (freshwater, marine, forest, grasslands, desert, Tundra) affect the ability of organisms to grow, survive and/or create their own food through photosynthesis.

+ Transfer of Energy Energy is derived (taken) from the sun and used by plants to produce sugars (photosynthesis) and is transferred within a food chain or food web from producers to consumers to decomposers.

+ Difference Between Food Chains and Food Webs Food webs: show how plants and animals are interconnected by different paths. Example: Trees produce acorns which provide food for mice and insects. Food chains: follows a single path as animals eat each other (or eat plants) Example: Cow eats grass Example: Shark eats seal

+ Types of Food Webs/Chains There are two places we find food webs/chains: on land and in water. On land they are called terrestrial In water they are called aquatic

+ What Are Producers? A producer is something that PRODUCES it’s own food! Plants food is glucose which is a type of sugar. They make this sugar using sun light, water, and carbon dioxide. This process is called photosynthesis.

+ What Are Consumers? Consumers must eat other things (plants or animals) to survive. There are three types of consumers: Herbivores: animals that eat only plants Example: cows, rabbits Carnivores: animals that eat only meat Example: T-rex, Omnivores: animals that eat both plants and animals

+ What Are Decomposers?

+ Bacteria and fungi are two types of decomposers. Decomposers return nutrients to the soil and air. They extract carbon from their food and it mixes with oxygen to create carbon dioxide. Examples are rotting logs, animals decaying, and mold on bread.

+ Bacteria in the Gut Gut flora or bacteria live in the digestive tract of most animals. These bacteria provide many useful functions for the host (the animal they live in) such as: Preventing growth of harmful bacteria Producing vitamins for the host Producing hormones that direct the host to store fat.

+ Bacteria in Plant Roots Bacteria live on plant roots and they convert nitrogen in the air into organic compounds (a chemical that contains carbon) that the plant can use. The plant then uses these organic compounds to make proteins that the animals will eat and use for energy.

+ Fun (and Important) Facts! In case you haven’t noticed, carbon is very important to plants and animals. Without carbon, life would not exist. Bacteria make up about 60% of the dry mass of feces (poop)!!

+ Levels of Organization Species- a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce Population- all member of one species in a particular area Community- all different populations that live together in an area

+ Predation An interaction in which on organism kills another for food Predator- the organism that does the killing Prey- the organism that is killed

+ Standard 6.L.2.2 Changes in Environmental Conditions Changes in environmental conditions can affect the survival of individual organisms and entire species.

+ Dormancy Dormancy is a period of inactivity in a mature seed prior to germination; seed remains dormant until conditions are favorable for growth and development of the new plant

+ Plants Adapt Plants grow, reproduce, and shift the position of their roots, stems and leaves in response to environmental conditions such as gravity, sunlight, temperature and day length.

+ Tropism Tropism is a plant’s turning or bending movement of an organism toward or away from an external stimulus such as light, heat or gravity. If the tropism is positive, the plant grows toward the stimulus. If the tropism is negative, the plant grows away from the stimulus

+ Biotic and Abiotic Factors Water, nitrogen, carbon dioxide, and oxygen are substances cycled between the living and non-living environments. Abiotic factors are any non-living things in an environment. Examples: air, water, sunlight Biotic factors are any living things in an environment. Examples: plants and animals Soil (organic matter) has both biotic and abiotic components.

+ Standard 6.L.2.3 Abiotic/Biotic Factors Refresher: What is the difference between abiotic and biotic factors? What are examples of each?

+ Different Environments Biomes: the world's major communities, classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment. Biomes we will focus on: Freshwater, marine, forest, grassland, tundra, desert Others include: tropical rainforest, mountain, savannah and tundra

+ Aquatic Biomes: Freshwater & Marine Freshwater: Includes streams, rivers, ponds and lakes Marine: covers about ¾ of the Earth’s surface and includes oceans, coral reefs and estuaries

+ Forest Biome: Large assortments of trees, plants and animals which vary depending on the zone’s climate

+ Grassland Biome An area that is populated mostly by grasses and other non-woody plants

+ Desert Biome An area that received less than 25 centimeters of rain a year

+ Tundra Biome Extremely cold and dry

+ Limiting Factors For Any Biome Environmental factors that affect an organism’s ability to survive in its environment, such as food availability, predators, and temperature, are limiting factors. A limiting factor is any biotic or abiotic factor that restricts the existence, number, reproduction, or distribution of organisms.

+ Limiting Factors Continued Can you think of a limiting factor that would affect the organisms around Overhills?

+ One Example of Limiting Factors At high elevations, the wind is too strong, temperatures too cold, and soil to thin to support the growth of large trees. All that grows in this environment is grasses, mosses, and ferns.

+ Limiting Factors Can Impact Multiple Species Example: water is limited in a grassland area, reducing the number of seeds produced. The rabbits depend on the grass for food. If there are fewer seeds, there’s less grass. Less grass= fewer rabbits. Hawks, which feed on rabbits, have less food in return.