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People have spread many plants beyond their native ranges; some of these plants have become invasive, damaging existing ecosystems by displacing native species, and sometimes becoming serious weeds of cultivation. [140] Some plants that produce windblown pollen, including grasses, invoke allergic reactions in people who suffer from hay fever. [141]
Land plants evolved from a group of freshwater green algae, perhaps as early as 850 mya, [3] but algae-like plants might have evolved as early as 1 billion years ago. [2] The closest living relatives of land plants are the charophytes, specifically Charales; if modern Charales are similar to the distant ancestors they share with land plants, this means that the land plants evolved from a ...
Sphenophyllum was a slender climbing plant with whorls of leaves, which was probably related both to the calamites and the modern horsetails. Cordaites, a tall plant (6 to over 30 meters) with strap-like leaves, was related to the cycads and conifers; the catkin-like inflorescence, which bore yew-like berries, is called Cardiocarpus. These ...
The life cycle of a dioecious flowering plant (angiosperm), the willow, has been outlined in some detail in an earlier section (A complex life cycle). The life cycle of a gymnosperm is similar. However, flowering plants have in addition a phenomenon called 'double fertilization'.
Oceanic islands have distributions of native plants and animals that are unbalanced in ways that make them distinct from the biotas found on continents or continental islands. Oceanic islands do not have native terrestrial mammals (they do sometimes have bats and seals), amphibians, or fresh water fish.
An image of multiple chromosomes, taken from many cells. Plant genetics is the study of genes, genetic variation, and heredity specifically in plants. [1] [2] It is generally considered a field of biology and botany, but intersects frequently with many other life sciences and is strongly linked with the study of information systems.
As this happens, the resulting cells will organize so that one end becomes the first root while the other end forms the tip of the shoot. In seed plants, the embryo will develop one or more "seed leaves" . By the end of embryogenesis, the young plant will have all the parts necessary to begin in its life. [citation needed]
Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. According to modern evolutionary biology, all living beings could be descendants of a unique ancestor commonly referred to as the last universal common ancestor (LUCA) of all life on Earth.