Environmental factors
Several million years ago, a species of small African ape gained the ability to stand upright. The subsequent advent of human life, and the development of agriculture and further civilisation allowed humans to affect the Earth more rapidly than any previous life form.
Since the Cambrian explosion there have been five distinctly identifiable mass extinctions. Affecting both the nature and quantity of other organisms as well as global climate. By comparison, the Great Oxygenation Event, produced by the proliferation of algae during the Siderian period, required about 300 million years to culminate.
The present era is classified as part of a mass extinction event, the Holocene extinction event, the fastest ever to have occurred.
| Period | Duration | Epochs | Events |
|---|---|---|---|
| Triassic | 51 Ma | Lower Triassic, Middle Triassic, Upper Triassic | Early dinosaurs, crocodiles, turtles; first mammals |
| Jurassic | 54 Ma | Lower Jurassic, Middle Jurassic, Upper Jurassic | Many seagoing reptiles; early large dinosaurs; later, flying reptiles (pterosaurs), earliest known birds |
| Cretaceous | 80 Ma | Lower Cretaceous, Upper Cretaceous | Dinosaurs and other reptiles dominate; seed-bearing plants appear |
Weather can have both beneficial and harmful effects. Extremes in weather, such as tornadoes or hurricanes and cyclones, can expend large amounts of energy along their paths, and produce devastation. Surface vegetation has evolved a dependence on the seasonal variation of the weather, and sudden changes lasting only a few years can have a dramatic effect, both on the vegetation and on the animals which depend on its growth for their food.
Climate is a measure of the long-term trends in the weather. Various factors are known to influence the climate, including ocean currents, surface albedo, greenhouse gases, variations in the solar luminosity, and changes to the Earth’s orbit. Based on historical records, the Earth is known to have undergone drastic climate changes in the past, including ice ages.
Weather is a chaotic system that is readily modified by small changes to the environment, so accurate weather forecasting is limited to only a few days.
The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria: these divisions are, in descending order of size:
the Pacific Ocean
The Atlantic Ocean
The Indian Ocean
The Southern Ocean
The Arctic Ocean
Smaller regions of the oceans are called seas, gulfs, bays and other names. There are also salt lakes, which are smaller bodies of landlocked saltwater that are not interconnected with the World Ocean. Two notable examples of salt lakes are the Aral Sea and the Great Salt Lake.
Ecosystems are composed of a variety of biotic and abiotic components that function in an interrelated way. The structure and composition is determined by various environmental factors that are interrelated. Variations of these factors will initiate dynamic modifications to the ecosystem. Some of the more important components are soil, atmosphere, radiation from the sun, water, and living organisms.
Weather is a chaotic system that is readily modified by small changes to the environment, so accurate weather forecasting is limited to only a few days.
The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean. Smaller regions of the oceans are called seas, gulfs, bays and other names. There are also salt lakes, which are smaller bodies of landlocked saltwater that are not interconnected with the World Ocean. Two notable examples of salt lakes are the Aral Sea and the Great Salt Lake.
Ecosystems are composed of a variety of biotic and abiotic components that function in an interrelated way. The structure and composition is determined by various environmental factors that are interrelated. Variations of these factors will initiate dynamic modifications to the ecosystem. Some of the more important components are soil, atmosphere, radiation from the sun, water, and living organisms.
Share
