In early spring, many wildflowers begin to grow, produce flowers, and release seeds. The leaves of the wildflowers make food before the leaves of the trees in the area begin to develop. The early growth pattern of the wildflowers would likely result in decreased competition for sunlight between the trees and the wildflowers (1). There is a good reason why the wildflowers grow so much earlier than the trees. If they start growing at the same time in spring, then the tree leaves will block out the sun for the wildflowers.
Answer: They cannot make their own food and must consume organic molecules to obtain energy.
One thing to realize about lichens is that they are not a single organism.
Lichens are a mutual symbiosis between algae and fungi, meaning the two work togehter.
The algae is able to survive making its own food by photosynthesis. It is able to survive on its own, but to spread, it needs special conditions that fungi are able to provide by anchoring it to the ground and providing nutrients.
The fungi can decompose dead organisms around it, but needs sugar from plants--such as algae--to survive.
Not much is needed for lichen to thrive, just sunlight, soil, and maybe some decaying organsims. This is why lichens are the pioneers of an ecological sucession.
Answer:
Temperatures in a desert climate range from 86 to 104 degrees Fahrenheit, while summers are wet and winters are dry. When the rains fall, herds of prey animals abound as they feed on the lush grasslands and water at the many waterholes and rivers. The average rainfall in the desert is 10 inches per year. Sahara desert vegetation includes African Welwitchsia, date palm, thyme, magaria, olive trees, orange trees, and fig trees. Apart from these, more than half of the Sahara desert is extremely barren with no vegetation found. However, there are still some areas in the Sahara desert that are lush, containing abundant trees and plants. The most common landscape features found in deserts are sand dunes, yardangs, desert pavements, debris, playas, oases, mesas, alluvial fans, arroyos and buttes. These landforms vary from desert to desert. In areas dominated by the tundra climate type, winters are long and cold, especially in the region north of the Artic Circle where, for at least one day in the year, the Sun does not rise. Winter precipitation generally consists of dry snow, with seasonal totals less than in the summer when cyclonic storms that develop along the boundary between the open ocean and sea ice yield rainfall. The average snowfall in the tundra is 10-40 inches per year. Tundra vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone between the tundra and the forest is known as the tree line or timberline. The arctic tundras located between the north pole and the coniferous forests or taigaregion. It is characterized by extremely cold temperatures and land that remains frozen year-round. Arctic tundra occurs in frigid mountaintop regions at very high elevations.