Unit 21.1
Living Things and the Environment Section 21.1 Organisms obtain food, water, shelter, and other things it needs to live, grow, and reproduce from its environment. An environment that provides these things for an organism is it s habitat.
Biotic and Abiotic Factors The living parts of a habitat are called biotic factors. The nonliving parts of the habitat are called abiotic factors.
Biotic and Abiotic Factors Fungi Water Berries Oxygen Sun Plants Worm Soil Prairie Dog Hawk Temperature Bacteria
Biotic and Abiotic Factors Fungi - Biotic Water - Abiotic Berries - Biotic Oxygen - Abiotic Sun - Abiotic Plants - Biotic Worm - Biotic Soil - Abiotic Prairie Dog - Biotic Hawk - Biotic Temperature - Abiotic Bacteria - Biotic
Levels of Organization All the members of one species living in a particular area is a population. All of the different populations that live in an area and interact make up a community. A community plus all of the abiotic factors in that habitat make an ecosystem.
populations not populations
communities
ecosystem
Levels of Organization
Levels of Organization
Levels of Organization The study of how living things interact with each other and with their environment is called ecology.
Studying Populations section 21.2 Determining Population Size 1. Direct observation (count the organisms) 2. Indirect observation (look for signs of organisms) 3. Sampling (count the organisms in a small area and make an estimate) 4. Mark and Recapture Studies (capture, mark, and release organisms, then recapture and look for marks)
Studying Populations Determining Population Size
Studying Populations section 21.2 Changes in Population Size Populations can change in size when new members join the population, or when members leave the population.
Changes in Population Size Births and Deaths The birth rate is the number of births in a population in a certain amount of time. The death rate is the number of deaths in a population in a certain amount of time. If birth rate > death rate, population size increases. If death rate > birth rate, population size decreases.
Changes in Population Size Immigration and Emigration Immigration means moving into a population Emigration means leaving a population.
Population Density Population density is the number of individuals in an area of a specific size.
Limiting Factors A limiting factor is an environmental condition that causes a population to decrease. 1. Food and Water 2. Space 3. Weather The largest population that an area can support is called carrying capacity. Populations and carrying capacity
Interactions among Living Things Section 21.3 Remember: Because of natural selection every organism has a variety of adaptations that are suited to it s specific living conditions. The role of an organism in it s habitat is called its niche. (what it eats, how it gets the food, what eats it, how and when it reproduces, physical conditions it needs to survive)
3 Interactions among Living Things Section 21.3 1. Competition Competition is the struggle between organisms to survive as they attempt to use the same limited resources.
3 Interactions among Living Things Section 21.3 2. Predation Predation is an interaction in which one organism kills another organism for food. Predators have adaptations that help them catch prey. Prey have adaptations that help them avoid being killed by predators.
3 Interactions among Living Things Section 21.3 3. Symbiosis Commensalism Mutualism Parasitism One organism benefits while the other is not harmed. Both organisms benefit. One organism benefits and the other is harmed.
Energy Flow in Ecosystems Section 22.1 Each of the organisms in an ecosystem fills the role of producer, consumer, or decomposer.
Energy Flow in Ecosystems Section 22.1 Producers An organism that can make its own food is a producer. They are the source of all the food in an ecosystem.
Energy Flow in Ecosystems Section 22.1 Consumer An organism that obtains energy by feeding on other organisms is a consumer. Consumers can be carnivores, herbivores, or omnivores.
Carnivores Consumers
Herbivores Consumers
Omnivore Consumers
Energy Flow in Ecosystems Section 22.1 Decomposer An organism that breaks down waste and dead organisms and returns the raw materials to the environment is a decomposer.
Food Chains and Food Webs A food chain is a series of events in which one organism eats another and obtains energy. A food web consists of the many overlapping food chains in a particular ecosystem.
Energy Pyramid An energy pyramid shows the amount of energy that moves from one feeding level to another in the food web. The most energy is available at the producer level of the pyramid. As you move up the pyramid, each level has less energy available than the level below.
Changes in Communities Section 21.4 The series of predictable changes that occur in a community over time is called succession.
Changes in Communities Section 21.4 Primary Succession is the series of changes that occur in an area where no soil or organisms exist. The first species to populate an area are called the pioneer species.
Changes in Communities Section 21.4 Secondary Succession occurs in a place where an ecosystem currently exists.
Changes in Communities Section 21.4 Lichens are compound creatures, formed from the symbiotic relationship between a algae and a fungus. They grow on rocks, tree trunks and branches.
Changes in Communities Section 21.4 When lichens die they create a weak acid that eats away at the rock, creating a soil where mosses can grow and in time larger bushes. Lichen are pioneer plants in succession.
Primary or Secondary Succession? State whether they are primary or secondary succession and HOW YOU KNOW:
Cycles of Matter Section 22.2 The Water Cycle The processes of evaporation, condensation and precipitation make up the water cycle.
The Water Cycle
Cycles of Matter Section 22.2 The Carbon and Oxygen Cycle The carbon and oxygen cycle traces the way producers, consumers, and decomposers each play a role in the linked recycling of carbon and oxygen in ecosystems.
The Carbon and Oxygen Cycle
Cycles of Matter Section 22.2 The Nitrogen Cycle In the nitrogen cycle, nitrogen moves from the air to the soil, into living things, and back into the air.
The Nitrogen Cycle
Freshwater Ecosystems Freshwater ecosystems include streams, rivers ponds and lakes.
Streams and Rivers Water currents flow strongest in streams which flow and join together forming larger, but slower moving rivers.
Ponds and Lakes Ponds are smaller bodies of still water where light can often reach the bottom. Lakes are generally larger than ponds and the water temperature varies between the top and the bottom depending on the season.
Freshwater Ecosystems Organisms Adaptations
Freshwater Ecosystems Organisms Adaptations
Adaptations: After reading about the organisms found in freshwater ecosystems explain what types of organisms are found in each environment, and what adaptations make them well suited for that environment.
Scavenger a consumer that eats dead organisms Primary consumer the first consumer in a food chain (eats a producer) Secondary Consumer the second consumer in a food chain (eats a primary consumer) Climax community a fully established (developed) ecosystem after succession.
BIOMES A biome is a group of land ecosystems with similar climates and organisms. It is mostly the climate (temperature and precipitation) that determines its biome. (That is because the types of organisms that can live in an area depends a lot on the climate.)
BIOMES There are 7 major biomes that most ecologists study: 1. Tundra
BIOMES There are 7 major biomes that most ecologists study: 2. Rainforest Temperate Rainforest Tropical Rainforest
BIOMES There are 7 major biomes that most ecologists study: 3. Deciduous Forest
BIOMES There are 7 major biomes that most ecologists study: 4.Taiga (boreal forest)
BIOMES There are 7 major biomes that most ecologists study: 5. Grassland (savannah)
BIOMES There are 7 major biomes that most ecologists study: 6. Desert
BIOMES There are 7 major biomes that most ecologists study: 7 and 8. Aquatic Biome Marine Freshwater