See also: taxonomy. The Earth's ecosphere was rapidly changing and throwing up a wide range of ecological niches that new adaptive organisms.. This tutorial looks at the mutation at the gene level and the harm it may bring. Learn about single nucleotide polymorph.. Plants and animals need elements, such as nitrogen, phosphorus, potassium, and magnesium for proper growth and developme.. Dinosaurs represented a major turn in the evolutionary development of organisms on Earth. The first dinosaurs were presu..
Plants are characterized by having alternation of generations in their life cycles. This tutorial is a review of plant m..
Allozyme studies in two-leaf pinyons Pinus edulis of the New York Mountains indicate that these populations are biochemically and genetically consistent with nearby one-leaf pinyon Pinus monophylla , and that P. The unusual New York Mountains population appears to be a 2-needle variant of P. According to Lanner, the latter species has five needles per fascicle and occurs in San Diego County.
The hybrid hypothesis might explain the perplexing variation in needle number for P. Foxtail pines Pinus balfouriana on the 11, ft m slopes of Alta Peak. The 13, ft. Left: Seed cones of cypress Cupressus from groves in southern California. Tecate cypress C. Sargent cypress C. Piute cypress C. Cuyamaca cypress C.
Smooth-bark Arizona cypress C. Rough-bark Arizona cypress C. Right: Seed cones of cypress from groves in central and northern California. Monterey cypress C. Gowen cypress C. Santa Cruz cypress C. Mendocino cypress C. Macnab cypress C. Modoc cypress C. Male pollen cones of the Piute cypress Cupressus nevadensis [syn. Each scalelike leaf bears a dorsal gland that exudes a resin droplet red arrow. Interior cypress species such as this one typically have glaucous, resinous foliage, presumably an adaptation to dry, arid habitats.
Foliage and pollen cones of the Smooth-bark Arizona cypress Cupressus glabra [Syn. Foliage of the Tecate cypress C. The scalelike leaves of Arizona cypress are glaucous and very glandular sticky.
The scalelike leaves of Tecate cypress are green and without dorsal resin glands. Right: Grove of Piute cypress C. The Piute cypress are more drought resistant, with gray glaucous , glandular resinous foliage similar to the Arizona cypress. In fact, some botanists now consider the Piute cypress to be a subspecies of the Arizona cypress and have named it C.
This species typically grows on outcrops of serpentine in the Coast Ranges of central and northern California. Serpentine is a shiny rock with a waxy luster and feel. It varies in color from creamy white and shades of green to black. In California, many species of rare and endangered plants are endemic to serpentine outcrops. Genetic drift has undoubtedly occured in isolated cypress groves such as this one, which are often referred to as "arboreal islands. Podocarpus gracilior , a member of the Podocarpaceae native to eastern Africa.
Although it is sometimes called "fern pine" it does not belong to the genus Pinus ; however, like pines and other cone-bearing species, it does belong to the Division Coniferophyta. Minute female cones are composed of reduced scales, but usually only one scale bears an ovule that matures into a seed. There is little resemblance to a cone in the mature seed.
The seed has a hard coat surrounded by a fleshy outer layer aril. The drupelike seed often sits on a fleshy red or purple base or cone axis that is called an aril in some references.
The seeds are similar to the California nutmeg Torreya californica and Pacific yew Taxus brevifolia , members of the closely-related Yew Family Taxaceae. In the latter species, the naked seed sits partially exposed in a red, cup-shaped aril. Podocarpus seeds are often referred to as fleshy fruits called drupes, but this is incorrect because drupes develop from the ovaries of flowering plants.
Another group of conifers with fleshy seed-bearing structures are the junipers Juniperus in the Cypress Family Cupressaceae. Junipers actually produce small cones with fleshy, fused scales bearing one-several seeds. Podocarpus is a dioecious species, with separate male and female trees in the population. Podocarpus has an ancient lineage dating back to distant relatives that lived during the Jurassic Period million years ago.
Like Podocarpus , the "naked" seed is enclosed in a fleshy, outer layer called an aril which superficially resembles a one-seeded fruit of an angiosperm. This diverse group contains vascular and nonvascular plants , flowering and nonflowering plants, as well as seed-bearing and non-seed bearing plants. As is true of most photosynthetic organisms, plants are primary producers and support life for most food chains in the planet's major biomes.
This kingdom includes animal organisms. These multicellular eukaryotes depend on plants and other organisms for nutrition. Most animals live in aquatic environments and range in size from tiny tardigrades to the extremely large blue whale. Most animals reproduce by sexual reproduction, which involves fertilization the union of male and female gametes.
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