Organic food

Sales of organic food in the US have grown nearly 20% during each of the last 6 years, and the 2002 release of the USDA's organic label added official weight to organic as a highly desirable class of food. Organic food has been shown to have more nutritional content, and children who eat mostly organic diets have been shown to have significantly lower levels of pesticides in their bodies.

The "USDA Organic" label is the gold standard of organic labeling. There are also many certifiers who have their own labels, and they are generally trustworthy. (For example, "Oregon Tilth" is one of the better known examples of certifier labels.) But there are labels other than organic that get applied to fruits, vegetables, and other products in your food market, and it's important to know what they mean.

Renewable energy

For the last 100 years or so we have been relying on fossil fuels to power our lifestyles, but this is now recognised as damaging to the environment and anyway, resources are limited. If we want to carry on enjoying our creature comforts then renewable energy is the way to do it.

Renewable energy is continually replenished by nature. Sources such as the sun, wind, water and thermal (underground) heat are harnessed rather than used up. The sun's energy can be converted using solar panels that can be placed on buildings or on posts, facing the sun.

The good news is they can be retro fitted onto the existing roof. If the roof is very old it may be worth hiring a structural engineer to confirm the load bearing capacity of your roof. Next find out how much electricity you use (your current electricity supplier will be able to let you know) and then decide what percentage of this you want your solar energy to replace. This will be a balancing trick. The price of solar panels will depend not only on efficiency but also on their capacity - also find out whether you can get any financial help from the Government or your local authority. This may depend on the system you choose.

Keystone Species — The Big Picture

It takes a great deal of study for scientists to understand the complexities and nuances of ecosystems and their keystone species, and there is still much work to be done. The important thing for us non-brainiacs to understand is the general concept of keystone species, the need to protect them, and the fact that there are many keystone species that have yet to be identified by scientists.

It's also worth considering the related concept of general species interaction. Even when an ecosystem does not radically change upon decline or loss of a particular species, it does change to some degree. This is often a natural process of evolution. But when the species losses are caused by external factors, the changes to the ecosystem cannot be passed off as "natural." Unnatural causes of habitat and ecosystem change include:

• overhunting, overfishing, or overharvesting;
• pollution;
• habitat encroachment from housing developments, agriculture, ranching, mining operations, or logging;
• invasion of non-native species (which are often introduced inadvertently via shipping or intentionally via illegal trade in exotic species);
• disappearance of predator species (which allows populations of prey species to explode);
• habitat change due to unnatural temperature changes in the environment (such as with global warming).

According to noted biologist E.O. Wilson, we are now seeing species extinctions at 1,000 times the normal rate, and there is no disagreement among biodiversity scientists that this is human-caused. How many of these lost species will turn out to have been keystone species? How much habitat change can our natural world withstand before a domino effect causes truly disastrous results?