* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Populations
Survey
Document related concepts
Biodiversity action plan wikipedia , lookup
Human impact on the nitrogen cycle wikipedia , lookup
Occupancy–abundance relationship wikipedia , lookup
Habitat conservation wikipedia , lookup
Biogeography wikipedia , lookup
Biological Dynamics of Forest Fragments Project wikipedia , lookup
Source–sink dynamics wikipedia , lookup
Overexploitation wikipedia , lookup
Lake ecosystem wikipedia , lookup
Human overpopulation wikipedia , lookup
Island restoration wikipedia , lookup
Human population planning wikipedia , lookup
Storage effect wikipedia , lookup
Renewable resource wikipedia , lookup
Maximum sustainable yield wikipedia , lookup
Transcript
Populations Populations – focus questions How does a change in one population affect another population? What is the biotic potential of a species? What factors affect the biotic potential of a species? What is environmental resistance? What factors contribute to environmental resistance? Factors which can limit the growth of a population include: Predation Shortage of food Disease Lack of water Lack of space Disaster Contamination of the Loss of habitat Environmental Resistance : Carrying Capacity “The largest number of individuals in a species that an environment can support” 4 factors that determine carrying capacity: 1. 2. 3. 4. Materials/energy Food Chains Competition Density Materials and Energy All populations are limited by the availability of resources: Energy (from the sun) Water Oxygen Carbon Nitrogen Other nutrients Food Chains The Pyramids of Biomass, Energy, and Numbers demonstrate how the population of a given organism is limited by: its position in a food chain/web the population size of those populations above and below it Relationships: Producer – consumer - decomposer Predator - prey Competition Ecosystems have limited resources. Organisms with similar needs must compete to get the resources they need. Supply versus Demand Competition occurs between: Members of the same species = Intraspecific competition Members of different species = Interspecific Competition Density An organisms’ need for space depends on their size, environment, and way of life. Different species have different needs for space. This need for space determines how many individuals of a given species can live in the same area at the same time. 1. 2. Factors affecting population size may be: Density-Dependent Factors Density-Independent Factors Density Dependent Factors If population density increases, it can cause a decrease in the population. Overcrowding leads to: Increased stress = spread of disease and parasites Increased aggression = neglect of offspring Reduced access to resources, mates and habitat Increased death rate/decreased birth rate =decrease in population Density Independent Factors Events that can decrease population size that are not related to how many individuals are in the population to begin with: Forest fire Flood Volcano Extreme weather (ex. Hurricane) Pollution How do humans manage biological variables to affect the carrying capacity of an ecosystem? Population Growth Curve Carrying Capacity Earth as Easter Island What is unique about Easter Island’s location? Describe what the first European explorers encountered upon arrival at Easter Island. How have the biotic factors on Easter Island changed over time? How has this affected the population? How do scientists know that many species of extinct plants and animals used to live on the island? What did the islanders use the trees for? How did the absence of trees affect the soil? Drinking water? Agriculture? Lessons from Easter Island? Resources Biotic Potential and Carrying Capacity of a Population