Environmental change and distribution of organisms COPY Flashcards
why might the distribution of organisms change
If the environment changes suddenly, the organisms there may not be well suited to these changes. Such changes might result from:
- living factors, such as humans, predators, or disease- causing microbes
- non-living factors, such as rainfall and temperature.
why is the bee population rapidly declining
Biologists believe that there are four reasons for the decline: • a virus that attacks the bee larvae • summers are cooler and damper • the use of agricultural chemicals • an increase in air pollution.
whats an example of a change in distribution of organisms
Many wading birds common to British estuaries are declining in numbers.
why are there much lower numbers of the ringed plover in britain nowadays
Birds such as the ringed plover used to migrate to Britain from the north for the milder winters. However, as the climate has become warmer throughout Europe during the winter, they have been moving to mainland Europe where the conditions are better.
what are environmental factors that may affect organisms (including living or non-living factors)
-change in numbers or types of competitor organism -temperature -availability of nutrients -amount of light -availability of water -availability of oxygen and carbon dioxide -availability of nesting sites, shelter and appropriate habitats
which living organisms can be used as air pollution indicators
lichens can be used as air pollution indicators, particularly of the concentration of sulfur dioxide in the atmosphere.
how does the distribution of lichen populations indicate differences in air pollution
Lichens are plants that grow in exposed places such as rocks or tree bark. Air pollutants dissolved in the rainwater they absorb, especially sulfur dioxide, can damage lichens, and prevent them from growing.
examples of the varying lichen populations showing difference in air pollution levels
-bushy lichens need really clean air -leafy lichens can survive a small amount of air pollution -crusty lichens can survive in more polluted air. In places where no lichens are growing, it is often a sign that the air is heavily polluted with sulfur dioxide.
what can invertebrate animals be used to indicate
invertebrate animals can be used as water pollution indicators and are used to indicate the concentration of dissolved oxygen in water
example of an invertebrate animal that is a water pollution indicator
rat-tailed maggots are invertebrate animals that are adapted to survive in water with very little oxygen. These maggots have a long, tail-like tube which is hollow. It acts like a snorkel, allowing the maggot to take in air containing oxygen from above the polluted water. This is why the maggot thrives in these conditions, and is an indicator species of polluted water.
what non-living indicators can also be used to measure environmental changes
oxygen levels, temperature and rainfall
disadvantages of using non-living indicators to measure environmental changes
Some forms of pollution such as dissolved salts or low oxygen levels in water are not so easy to see. To monitor those all the time would be costly and involve lots of time consuming analytical tests. Indicator species provide an easy to see and quick method of qualitatively checking air and water pollution.
measuring oxygen levels using non-living indicators
oxygen levels in water can be measured using oxygen probes. These are often connected to a data logger.
measuring temperature using non-living indicators
An ordinary thermometer can be used to measure the temperature in an environment. Traditional maximum and minimum thermometers have a U-shaped tube. Each side contains a pin which moves inside with the liquid: one pin records the maximum temperature; and the other pin records the minimum temperature. After readings have been taken, the pins are reset using a magnet. A digital thermometer connected to a data logger allows an almost continuous measurement of temperature over time. It also has the advantage that no one needs to be there to take a reading.
measuring rainfall using non-living indicators
Rainfall is measured using a rain gauge. The depth of rain is usually measured daily, for example at the same time every morning. A simple rain gauge consists of a funnel that empties into bottle. The daily contents of the bottle are poured into a measuring cylinder that is calibrated so that it reads the depth of rainfall in millimetres.
