Bio Wk 2 Niches, Consequences, and Sampling techniques

• Niche 

  • Where you are most likely to be living. E.g you will be most likely to be found in your bedroom at your house
• Ecological niche

  • All of the activities, relationships, and interactions a species has within an ecosystem
• Habitat

  • Where an organism lives. Within every habitat, there are microhabitats. Each microhabitat has its climate, known as a microclimate
• Feeding niches

  • Often species will partition their resources based on time and location. For example, different heights of a tree can serve different birds
• Predation and competition

  • All herbivore and omnivores and carnivores are predators as well
• Intraspecific competition

  • Is usually more intense as the organisms have far more resource needs in common
• Interspecific competition

  • May lead to the evolution of one of the species in response to the selection pressure exerted by the other species that alters its niche.
• Predicting consequences for populations in ecosystems

  • Scientists use models such as graphs so that they can easily visualize trades and help them to make predictions for the future
• Consequences of predation

  • Predation affect the distribution and abundance of their prey
• Consequences of symbiosis

  • Increased evolutionary diversification
• The graph of the population rates of prey and predators

  
• Sampling techniques

  • To determine size or abundance of species in a given area and it’s range or distribution
• 3 main sampling techniques; transect, quadrat, capture-recapture
• Transects

  • A line or strip for counting and mappping the number of individuals at different distances along the line
• Types of transects

  • Line transect 
  • Belt transect
• Quadrats

  • Is a defined area used in an ecological study to measure the distribution abundance or density.
• Quadrat technique

  Is you are counting blades of grass in the school larn, you would use a small quadrat (10cm x 10cm)
• Capture-recapture

  Process

  Mark → release → recapture
• Steps For quadrat sampling technique

  1. A small sample of a population is captured
  2. They are given a marking or tag and released back into the wild
  3. A new sample of the population is collected
  4. The number of marks individuals in this sample is the population
  5. Population can be estimated from the ratio of marked to unmarked
• Quadrat formula

  Number captured/marked x number recaptured

  Number of marked in recapture
• Capture-mark-recapture is based on several assumptions:

  • All animals have the same probability of being captured in the second sample whether they were caught in the first sample or not
  • The rates for birth, death, immigration, and emigration were low in the time frame between the first capture and second capture