The Organism in the Environment

The Organism in the Environment

The Organism in their Environment

Characteristics of Living Things

  • Living things or organisms share seven common characteristics: movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition.
  • Remember these traits with the acronym MRS GREN.

Habitats and Adaptation

  • A habitat is where an organism lives, it includes both living and non-living components.
  • Organisms are adapted to their habitats in a variety of ways that increase their chances of survival and reproduction.
  • Structural adaptations are physical features of an organism’s body; e.g., a camel’s hump stores fat.
  • Behavioural adaptations are ways organisms behave; e.g., polar bears hibernate in winter.
  • Physiological adaptations are internal body processes, for example, many desert animals conserve water.

Population and Community

  • A population is a group of individuals of the same species in a given area.
  • Community refers to all populations in a specific area existing together, which includes different species.
  • Interactions in a community include: predation, competition, and symbiosis.

Ecosystem Composition

  • An ecosystem consists of all the organisms (biotic component) in a community, plus the physical environment (abiotic component).
  • The physical environment includes living and non-living aspects—like weather and soil type—that may influence organisms.

Energy Flow in Ecosystem

  • Energy enters most ecosystems as sunlight and gets converted into chemical energy by producer organisms (like plants) through photosynthesis.
  • This energy is passed along the food chain as organisms eat one another.
  • Each step or level in a food chain is called a trophic level.
  • Every time energy is transferred between trophic levels, some is lost as heat.

Locating and Identifying Species

  • Sampling techniques are used to investigate the distribution and abundance of species in a habitat.
  • Techniques include quadrat sampling for plants, pitfall traps for small animals, and sweep-netting for insects.
  • All data collected should be handled responsibly due to ethical considerations.

Pollution and Climate Change

  • Human activities cause pollution, which may have negative effects on biodiversity and cause climate change.
  • Pollution includes air pollution leading to acid rain, and water pollution causing eutrophication and oil spills.
  • Indicators species can be used to assess the level of pollution in an environment.
  • Human-induced climate change is causing shifts in species’ distribution and the timing of natural events.