Marine ecosystems cover approximately 71% of the Earth's surface and contain approximately 97% of the planet's water. They generate 32% of the world's net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, in the water. Approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has an average salinity of 35 parts per thousand(ppt) of water. Actual salinity varies among different marine ecosystems.
A classification of marine habitats.
Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides; in this figure it is termed the littoral zone. Other near-shore (neritic) zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web.
Classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fishes caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations.
Environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources (for example overfishing of certain species), marine pollution,climate change, and building on coastal areas.
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Answer:
<em>- Galileo used a telescope to study the moons orbiting Jupiter. This showed that Earth was not the center of all things.</em>
<em>-Galileo discovered the phases of Venus, proving that at least one planet orbited the Sun.</em>
Explanation:
Galileo discovered evidence to support Copernicus’ heliocentric theory when he observed four moons in orbit around Jupiter. Beginning on January 7, 1610, he mapped nightly the position of the 4 “Medicean stars” (later renamed the Galilean moons). Over time Galileo deduced that the “stars” were in fact moons in orbit around Jupiter.
At about the same time, German mathematician Johannes Kepler was publishing a series of laws that describe the orbits of the planets around the Sun. Still in use today, the mathematical equations provided accurate predictions of the planets’ movement under Copernican theory. In 1687, Isaac Newton put the final nail in the coffin for the Aristotelian, geocentric view of the Universe. Building on Kepler’s laws, Newton explained why the planets moved as they did around the Sun and he gave the force that kept them in check a name: gravity.
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Answer:
Facilitated diffusion in a cell has a limited amount of carrier and channel proteins, wherein if all are being used or saturated, can't transport the substances outside in to the cell, leading to the plateau of the substance.
Explanation:
In <u>low concentrations</u> of the substance outside the cell, <u>facilitated diffusion behaves like simple diffusion</u>, carriers and channels are not all used up. But in instances of <u>high concentration of the substance</u> outside the cell, <u>all the carrier and channel proteins are occupied</u> with the said substance. So <u>even if we increase the concentration of the substance, it will not increase the rate of diffusion.</u>
The right answer is b. Tree.
Some plants (like trees) have evolved with different unusual nutritional adaptations over time. Heterotrophic plants are plants that use only or partly a source of organic carbon to grow, unlike the most common autotrophic plants, which use inorganic carbon and water to grow, often through the process of photosynthesis (photoautotrophic).
