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Periphyton can contain species of cyanobacteria that are toxic to humans and other animals. [1] In fresh water, excessive growth and subsequent death and decay of periphyton can have undesirable effects: depleting oxygen in the water, altering its pH, and clogging the space between gravel and sand (the hyporheic zone).
Some animal species use bioaccumulation as a mode of defense: by consuming toxic plants or animal prey, an animal may accumulate the toxin, which then presents a deterrent to a potential predator. One example is the tobacco hornworm, which concentrates nicotine to a toxic level in its body as it consumes tobacco plants. Poisoning of small ...
Air pollution can cause diseases, allergies, and even death; it can also cause harm to animals and crops and damage the natural environment (for example, climate change, ozone depletion or habitat degradation) or built environment (for example, acid rain). [2] Air pollution can occur naturally or be caused by human activities. [3]
Toxic: a chemical that has a median lethal concentration (LC 50) in air of more than 200 parts per million (ppm) but not more than 2,000 parts per million by volume of gas or vapor, or more than 2 milligrams per liter but not more than 20 milligrams per liter of mist, fume or dust, when administered by continuous inhalation for 1 hour (or less if death occurs within 1 hour) to albino rats ...
About 200 Americans are killed per year by animals, according to one study, and the most common perpetrators may be surprising. ... Dogs are next with 28 human victims, and cows kill about 20 ...
The Deadliest Animal in the World, Gates Notes; These Are The Top 15 Deadliest Animals on Earth, Science Alert; Top 10 Deadliest Animals To Humans In The World, Toptenia; The 25 Most Dangerous Animals In The World, List 25; The Most Dangerous Animals in the World, Animal Danger; Top 10 Most Dangerous Animals In The World, Conservation Institute
Natural range extensions are common, but humans often carry specimens faster and over greater distances than natural forces. [56] An early human vector occurred when prehistoric humans introduced the Pacific rat (Rattus exulans) to Polynesia. [57] Chinese mitten crab. Vectors include plants or seeds imported for horticulture. The pet trade ...
The period since 1950 has brought "the most rapid transformation of the human relationship with the natural world in the history of humankind". [106] Through 2018, humans have reduced forest area by ~30% and grasslands/shrubs by ~68%, to make way for livestock grazing and crops for humans. [107]