Hot answers tagged

36 votes
Accepted

Why is a mosquito feeding on human blood not a parasite?

A mosquito is a biological parasite, it is not a medical parasite. There are two definitions of parasite. A biological/ecological definition and a medical/physiological interaction definition. A ...
  • 13.3k
33 votes

Why haven't prey evolved the ability to always outrun their predators?

There are (at least) three important factors to consider here; evolution under selection requires genetic variation upon which to act, selection can act on covarying traits causing trade-offs, and ...
  • 16k
33 votes
Accepted

Earth overshoot day: is it a sound concept?

TL;DR: it's a simplified measure of sustainability, but accurate enough to be useful for public engagement EOD is hosted and calculated by Global Footprint Network (GFN), an international think tank....
  • 3,348
30 votes
Accepted

Can beavers control the direction a tree falls?

It is difficult to find a scientific answer to this question, but let me insert this citation from a specialist site: Contrary to popular belief, beaver cannot plan the direction in which trees ...
  • 5,630
23 votes
Accepted

What is Growing on These Tree Leaves? (Image)

This is actually not a gall as other answers have suggested. This is likely a fungus called Cedar-apple rust (Gymnosporangium juniperi-virginianae). The fungus only thrives in the presence of both ...
22 votes
Accepted

How to get rid of mosquitoes in a small lake

There are a number of environmentally destructive methods that would be effective, including draining the lake, covering the surface with a continuous layer of oil, or adding toxins to the water, but ...
  • 3,348
22 votes

What exactly is this small puffer fish doing and how did it manage to accomplish such a feat?

A tiny Japanese puffer fish creates a grand sand sculpture on the featureless seabed by using his fins to dig furrows. He uses this to attract the attention of passing females. Why do puffer ...
  • 1,562
20 votes
Accepted

Inexperienced divers damage coral, but parrot fish eating coral doesn't do damage?

You are absolutely correct in regards that marine life does cause damage to corals. In particular, parrotfish have been found to play an important role in regulating the biodiversity of coral reefs ...
  • 1,007
19 votes
Accepted

Are there phage-eating bacteria?

It's suspected that some protists (namely choanozoans and picozoans) are proper/direct "virus eaters" due to the size of their "eating apparatus" and scarcity of bacterial remains ...
  • 3,042
17 votes

Why haven't prey evolved the ability to always outrun their predators?

There are two reasons for this: evolutionary trade-offs and coevolution (the "Red Queen hypothesis", as mentioned in the comment above by Luigi). Evolutionary trade-off describes situations where one ...
  • 3,348
17 votes

Earth overshoot day: is it a sound concept?

I think that your question comes from a misunderstanding in the definition of the overshoot day, here is the definition in your question: Regardless of how it's calculated, the claim that we have ...
  • 307
17 votes

Antibacterial soap impacts on septic system?

The quick answer is: Yes, it can cause harm. Think about it...The septic system (both the tank and your drain field) rely on bacteria, and antibacterial soap is not designed to kill only specific ...
16 votes

What exactly is this small puffer fish doing and how did it manage to accomplish such a feat?

This "nest" is created by a male pufferfish for both courtship and for rearing young. The male puffer fish uses its body and fins (a combination of pectoral, anal, and caudal -- see here) to ...
15 votes
Accepted

How did zootoxins evolve?

General overview. Each toxin and poison probably have their own evolutionary "arms race". Generally, an organism contains a compound that is a bit harmful to other species. As a predator or ...
  • 11.3k
14 votes
Accepted

Are there species that occupy several roles in the food hierarchy?

Food hierarchy and food web Ecological trophic interactions are better represented by food webs rather than simple hierarchical relationships. As a consequence, the concepts of primary/secondary/...
  • 67.7k
14 votes
Accepted

Why do birches have a white bark?

It is protection against rapid warming of the cambium layer. A lot of far northern timber has light colored bark which reflects sunlight. The rapid heating from very cold after sunrise can actually ...
  • 13.3k
13 votes
Accepted

Where can I find historical data on world-wide ecology parameters?

Adding some additional database sources: -- Climate -- Prism The PRISM Climate Group gathers climate observations from a wide range of monitoring networks, applies sophisticated quality control ...
13 votes
Accepted

How big should the human population be, as predicted by body mass?

It is certainly possible to use general relationships to predict human population density or abundance. The relationship between population density/abundance and body size is an old topic in ecology ...
12 votes
Accepted

Does rainwater contain many fewer micro-organisms than river water?

According to a number of citations listed on Kenyon College's MicrobeWiki, rain can contain microorganisms via a process called "bioprecipitation." Essentially, microorganisms, dust and other small ...
12 votes
Accepted

Which anaerobic environments would exist without aerobic life?

In the question body it says: After the great oxygenation event, there was oxygen in the atmosphere but no layers of aerobic life to stop it from diffusing to the bottom of the ocean or deep ...
  • 8,759
11 votes
Accepted

Why are flies not scared when landing on a monitor with changing graphics?

Flies see motion. When the monitor screen changes, the visible spectrum of the pixel is changing and nothing is moving. Flies have limited color vision. Each color has its own wave frequency, but ...
  • 2,167
11 votes

Why is a mosquito feeding on human blood not a parasite?

Short answer Female* mosquitoes are generally not to be considered ectoparasites because they spend so little time with the host. Instead, they are sometimes classified as micro-predators. *Male ...
  • 51.5k
11 votes
Accepted

What is full form of r and K in r-selection species and K-selection species?

This article discusses the origin of the terms. They come directly from the equation used to describe population dynamics. As Canadianer mentioned the Wiki also covers it quite well. "r" stands for "...
  • 13.3k
11 votes
Accepted

What is the body density of insects on average?

A recent studya measured the volumes (using a 3D scanner) and masses of 113 different insect species. They found the following relationship between the mass of the insects and their volumes ($V[mm^3]$ ...
  • 2,068
10 votes

Can humans transdermally absorb minerals from ocean water, and if so how much?

There is not very much transport of ions or water through the upper layer of the skin, mainly responsible for that is the stratum corneum (SC). Through this layer you will get only with small lipids ...
  • 49.4k
10 votes
Accepted

Algae or Lichen identification. Coastal BC, Canada

I want to propose you expand your search to a broader taxonomic scope. Specifically, I think you might be looking at a species of "red" green algae (family: Trentepohliaceae). From Nelson ...
9 votes

What is called the "area size that an animal usually lives in"?

Are you looking for 'Home range' (see also the definition in Encyclopaedia Britannica)? Generally, 'home range' is defined as the entire area an individual animal uses, while the 'territory' is the ...
9 votes

What is the distinction between the terms detrivores, decomposers, saprotrophs and saprozoic organisms?

Detritivores consume (eat) detritus. Saprotrophs feed on dead organic matter by the means of extracellular digestion. Saprozoic organisms are protozoans that are saprotrophs. This actually comes ...
  • 35.1k
9 votes
Accepted

Do camels pose an environmental threat to kangaroos?

Feral camels have environmental, economic and cultural impacts in Australia's Northern Territory (Dept of Land Resource Management, Australia). In central Australia, camels feed on more than 80% of ...
  • 51.5k

Only top scored, non community-wiki answers of a minimum length are eligible