What is the importance of photosynthesis in an …
What is the significance of photosynthesis
Ornithischians started slowly and began to become common in the late Jurassic, just when the greatest biological innovation in the past 300 million years began: the appearance of , which first bloomed about 160 mya. Until that time, plant survival strategies included how to avoid being eaten by animals, whether it was bark, height, poisonous foliage, etc. Flowering plants adopted a different strategy by laying out a banquet for animals. The primary benefit for plants was , as well as attracting animals that did not seek to eat the plants and even ended up protecting them. The advantage for animals was an easily acquired and tasty meal. It was the greatest direct symbiosis between plants and animals ever, other than plants providing the oxygen that animals breathe, which is inadvertent. The two primary aspirations that seed plants achieve for successful reproduction are becoming fertilized via pollination and placing seeds where they can become viable offspring (and feces fertilizer could only help). Flowering plants, also called angiosperms, did not invent animal assistance from whole cloth. Some Jurassic insects have been found in association with (conifer) cones, and were probably doing the work that the wind previously performed. Like the , attracting animals to plants, to eat the pollen and nectar, was like a reproductive enzyme: animals carried the key to the lock to initiate reproduction. Other animals ate the fruit and thereby spread the seeds. That relationship did not become significant until the mid-Cretaceous. Angiosperms mature faster and produce more seeds than gymnosperms do. By the Cretaceous’s end, angiosperms dominated tropical biomes where ferns and cycads used to thrive, and they pushed conifers to the high latitudes, just as they have today. That tropical dominance is probably related to the insect population, which prefers warm climates. Angiosperms became Earth’s dominant plants after the and comprise more than 90% of plant species today.
What is photosynthesis, and how does it work?
When sea levels rise as dramatically as they did in the Cretaceous, coral reefs will be buried under rising waters and the ideal position, for both photosynthesis and oxygenation, is lost, and reefs can die, like burying a tree’s roots. About 125 mya, reefs made by , which thrived on , began to displace reefs made by stony corals. They may have prevailed because they could tolerate hot and saline waters better than stony corals could. About 116 mya, an , probably caused by volcanism, which temporarily halted rudist domination. But rudists flourished until the late Cretaceous, when they went extinct, perhaps due to changing climate, although there is also evidence that the rudists . Carbon dioxide levels steadily fell from the early Cretaceous until today, temperatures fell during the Cretaceous, and hot-climate organisms gradually became extinct during the Cretaceous. Around 93 mya, , perhaps caused by underwater volcanism, which again seems to have largely been confined to marine biomes. It was much more devastating than the previous one, and rudists were hit hard, although it was a more regional event. That event seems to have , and a family of . On land, , some of which seem to have , also went extinct. There had been a decline in sauropod and ornithischian diversity before that 93 mya extinction, but it subsequently rebounded. In the oceans, biomes beyond 60 degrees latitude were barely impacted, while those closer to the equator were devastated, which suggests that oceanic cooling was related. shows rising oxygen and declining carbon dioxide in the late Cretaceous, which reflected a general cooling trend that began in the mid-Cretaceous. Among the numerous hypotheses posited, late Cretaceous climate changes have been invoked for slowly driving dinosaurs to extinction, in the “they went out with a whimper, not a bang” scenario. However, it seems that dinosaurs did go out with a bang. A big one. Ammonoids seem to have been brought to the brink with nearly marine mass extinctions during their tenure on Earth, and it was no different with that late-Cretaceous extinction. Ammonoids recovered once again, and their lived in the late Cretaceous, but the end-Cretaceous extinction marked their final appearance as they went the way of and other iconic animals.