Search results
Results from the WOW.Com Content Network
Pollinator decline is the reduction in abundance of insect and other animal pollinators in many ecosystems worldwide that began being recorded at the end of the 20th century. Multiple lines of evidence exist for the reduction of wild pollinator populations at the regional level, especially within Europe and North America.
Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirable (from the International Atomic Energy Agency (IAEA) definition).
[5] [6] Further problem areas are air and water pollution (including nutrient pollution), over-exploitation, invasive species [7] and climate change. [ 4 ] Many scientists, along with the Global Assessment Report on Biodiversity and Ecosystem Services , say that the main reason for biodiversity loss is a growing human population because this ...
Radio spectrum pollution is the straying of waves in the radio and electromagnetic spectrums outside their allocations that cause problems for some activities. [1] It is of particular concern to radio astronomers. Radio spectrum pollution is mitigated by effective spectrum management.
Diffuse source pollution from agricultural fertilizers is more difficult to trace, monitor and control. High nitrate concentrations are found in groundwater and may reach 50 mg/litre (the EU Directive limit). In ditches and river courses, nutrient pollution from fertilizers causes eutrophication. This is worse in winter, after autumn ploughing ...
Honey bees at a hive entrance: one is about to land and another is fanning. Colony collapse disorder (CCD) is an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees. [1]
Buzz pollination or sonication is a technique used by some bees, such as solitary bees and bumblebees, to release pollen which is more or less firmly held by the anthers. [1] The anthers of buzz-pollinated plant species are typically tubular, with an opening at only one end, and the pollen inside is smooth-grained and firmly attached.
Pollen itself is not the male gamete. [4] It is a gametophyte, something that could be considered an entire organism, which then produces the male gamete.Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.