Populations and Communities Table of Contents Living Things
Populations and Communities Table of Contents Living Things and the Environment Studying Populations Interactions Among Living Things Changes in Communities
Populations and Communities Essential Question How do living things affect one another?
Populations and Communities Lesson 1 Objectives: 1. Identify the needs that must be met by an organism’s surroundings. 2. Identify biotic and abiotic parts of a habitat. 3. Describe the levels of organization within an ecosystem.
Populations and Communities Living Things and The Environment All living things must interact with their surroundings. Organism —a complete and whole living thing Habitat —a place where an organism lives. It provides food, water, shelter and a place to reproduce. Ex: a woodpecker’s habitat is the trees in a forest. Niche —the role of an organism in its community. How it makes a living. Ex: a woodpecker’s niche is catching and eating insects.
Populations and Communities Biotic and Abiotic Factors Biotic Factors —all living parts of an organism’s habitat. Abiotic Factors —all nonliving parts of an organism’s habitat. (water, sunlight, oxygen, temperature, soil)
Populations and Communities Levels of Organization The living things in an environment must be organized into larger and larger groups within their environment. Species —a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce. Populations —all the members of one species in a particular area. Community –- all the different populations that live together and interact with each other in a particular area.
Populations and Communities Levels of Organization Ecosystem —the community of organisms that live in a particular area, along with their nonliving surroundings. Ex: pond, garden, forest Biosphere —the entire region of the world where living things are found. Ecology —the study of how living things interact with each other and with their environment
Populations and Communities Living Things and the Environment Levels of Organization The smallest level of organization is a single organism, which belongs to a population that includes other members of its species.
Populations and Communities Living Things and the Environment Levels of Organization The population belongs to a community of different species.
Populations and Communities Living Things and the Environment Levels of Organization The community and abiotic factors together form an ecosystem.
Populations and Communities Four Characteristics of a Self-sustaining Ecosystem A self-sustaining ecosystem has four characteristics: 1. A constant source of energy (usually the sun) 2. Transfer of energy into organic compounds (usually through photosynthesis) 3. Interactions between biotic factors (predator/prey, mutualism, commensalism) 4. Cycling of materials (water cycle, nitrogen cycle, oxygen/carbon dioxide cycle, nutrient cycle)
Populations and Communities Lesson 2 Objectives: 1. Explain the causes of changes in population size. 2. Identify factors that limit population growth.
Populations and Communities Studying Population Size Four methods of determining population size: 1. Direct Observation —count all members of a population. 2. Indirect Observation —observe and count signs of a population. Ex: count nests or dens observed 3. Sampling —make an estimate of the population by counting the number of organisms in a small area (a sample), and then multiplying to find the number in a larger area. Estimate —an approximation of a number. 4. Mark-and-Recapture Studies —capture, mark, and release organisms several times to calculate their population number.
Populations and Communities Changes in Population Size Populations can change in size when members either leave or join the population. Population size can change by births, deaths, immigration or emigration. Birth rate —number of births in a population in a certain amount of time. Death rate —number of deaths in a population in a certain amount of time. Birth rate > Death rate = population increase Death rate > Birth rate = population decrease Immigration —organisms move into a population Emigration —organisms move out of a population
Populations and Communities Population Density —the number of individuals in a specific area. Population Density = Number of individuals Unit area
Populations and Communities Studying Populations Changes in Population Density In many situations, it is helpful to know the population density –the number of individuals in a specific area. Population density =
Populations and Communities Limiting Factor —an environmental factor that causes a population to decrease. They include: food, water, space, and weather conditions Limiting Factors help determine the carrying capacity of an environment. Carrying Capacity —the largest population that an area can support.
Populations and Communities Studying Populations Changes in Population Size Populations can change in size when new members join the population or when members leave the population.
Populations and Communities Lesson 3 Objectives: 1. Explain how adaptations help an organism survive. 2. Describe competition and predation. 3. Identify three types of symbiosis.
Populations and Communities Adapting to the Environment Each organism in a community has unique characteristics that allow them to interact with each other and to survive. Adaptations —the behaviors and physical characteristics that allow organisms to live successfully in their environment. Natural Selection —individuals with the best adaptations will survive to pass on these traits to their offspring. These better characteristics will therefore become more common in the population.
Populations and Communities Interactions Among Living Things Adapting to the Environment Every organism has a variety of adaptations that are suited to its specific living conditions.
Populations and Communities Interactions Among Living Things There are three major types of interactions among organisms: Competition, Predation, and Symbiosis 1. Competition —the struggle for organisms to survive as they attempt to use the same limited resources. Animals compete for food, water, shelter, territory and mates Plants compete for sunlight, water and growing space
Populations and Communities 2. Predation —one organism kills another food. Predator —does the killing Prey —is killed -It helps control overpopulation of non-predatory species. -It helps weed out diseased or less-fit members of a non-predatory species. -Populations of predators and their prey rise and fall in related cycles.
Populations and Communities Interactions Among Living Things 3. Symbiosis —a close relationship between two species that benefits at least one of the species. Three types: -Mutualism —both species benefit Example—bees visit flowers: bees get nectar and flowers get pollinated. Example—lichens: a mutual relationship between algae and fungi: algae makes food for the fungi and the fungi makes living conditions better for the algae.
Populations and Communities -Commensalism —one species benefits and the other is neither helped nor harmed. Example: barnacles attached to gray whales: barnacles get a free ride to find food and the whale is unaffected. Gray whales can be identified by their barnacle patches. Some may carry as much as 400 lbs of barnacles and whale lice. Example: orchid growing on a tree: orchid gets a place to grow and the tree is unaffected
Populations and Communities -Parasitism —one species benefits and the other is harmed. -Parasite —organism that benefits -Host —organism that the parasite lives in or on and is harmed. 1. Hookworm 2. Tapeworm 3. Tapeworm eggs 4. Roundworm 5. Pin worm
Populations and Communities Lesson 4 Objective: 1. Explain the difference between primary and secondary succession.
Populations and Communities Changes in Communities change constantly---sometimes suddenly; sometimes slowly. Succession —the series of predictable changes that occur in a community over time. Two types: 1. Primary Succession —the series of changes that occur in an area where no soil or organisms exist. Example: Following a volcanic eruption. Pioneer species —first species to populate such an area. Examples: mosses and lichens
Populations and Communities Changes in Communities Primary Succession Primary succession is the series of changes that occur in an area where no soil or organisms exist.
Populations and Communities Changes in Communities 2. Secondary Succession —the series of changes that occur in an area where the ecosystem has been disturbed, but where soil and organisms still exist. Examples: following fires, hurricanes, tornados, farming, logging or mining.
Populations and Communities Changes in Communities Secondary Succession Secondary succession is the series of changes that occur in an area where the ecosystem has been disturbed, but where soil and organisms still exist.
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