Today, we look at the most fundamental human characteristic:
A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation for example, the large muscles of a weightlifter.
Any heritable characteristic of an organism that improves its ability to survive and reproduce in its environment. Also used to describe the process of genetic change within a population, as influenced by natural selection.
A graph of the average fitness of a population in relation to the frequencies of genotypes in it. Peaks on the landscape correspond to genotypic frequencies at which the average fitness is high, valleys to genotypic frequencies at which the average fitness is low.
Also called a fitness Evolution of bipedal locomotion. A behavior has adaptive logic if it tends to increase the number of offspring that an individual contributes to the next and following generations. If such a behavior is even partly genetically determined, it will tend to become widespread in the population.
Then, even if circumstances change such that it no longer provides any survival or reproductive advantage, the behavior will still tend to be exhibited -- unless it becomes positively disadvantageous in the new environment.
The diversification, over evolutionary time, of a species or group of species into several different species or subspecies that are typically adapted to different ecological niches for example, Darwin's finches. The term can also be applied to larger groups of organisms, as in "the adaptive radiation of mammals.
A mode of coping with competition or environmental conditions on an evolutionary time scale. Species adapt when succeeding generations emphasize beneficial characteristics.
A person who believes that the existence of a god or creator and the nature of the universe is unknowable. An umbrella term for various simple organisms that contain chlorophyll and can therefore carry out photosynthesis and live in aquatic habitats and in moist situations on land.
The term has no direct taxonomic significance.
Algae range from macroscopic seaweeds such as giant kelp, which frequently exceeds 30 m in length, to microscopic filamentous and single-celled forms such as Spirogyra and Chlorella. One of the alternative forms of a gene. For example, if a gene determines the seed color of peas, one allele of that gene may produce green seeds and another allele produce yellow seeds.
In a diploid cell there are usually two alleles of any one gene one from each parent. Within a population there may be many different alleles of a gene; each has a unique nucleotide sequence. The relation between the size of an organism and the size of any of its parts.
For example, an allometric relation exists between brain size and body size, such that in this case animals with bigger bodies tend to have bigger brains. Allometric relations can be studied during the growth of a single organism, between different organisms within a species, or between organisms in different species.
Speciation that occurs when two or more populations of a species are geographically isolated from one another sufficiently that they do not interbreed. Living in separate places. The unit molecular building block of proteinswhich are chains of amino acids in a certain sequence.
There are 20 main amino acids in the proteins of living things, and the properties of a protein are determined by its particular amino acid sequence. A series of amino acids, the building blocks of proteinsusually coded for by DNA. Extinct relatives of cephalopods squid, octopi, and chambered nautilusesthese mollusks had coiled shells and are found in the fossil record of the Cretaceous period.
The group of reptiles, birds, and mammals. These all develop through an embryo that is enclosed within a membrane called an amnion. The amnion surrounds the embryo with a watery substance, and is probably an adaptation for breeding on land. The class of vertebrates that contains the frogs, toads, newts, and salamanders.
The amphibians evolved in the Devonian period about million years ago as the first vertebrates to occupy the land. They have moist scaleless skin which is used to supplement the lungs in gas exchange.
The eggs are soft and vulnerable to drying, therefore reproduction commonly occurs in water. Amphibian larvae are aquatic, and have gills for respiration; they undergo metamorphosis to the adult form.
Most amphibians are found in damp environments and they occur on all continents except Antarctica. Structures in different species that look alike or perform similar functions e. Contrast with homologous structures. The recent discovery of deep genetic homologies has brought new interest, new information, and discussion to the classical concepts of analogous and homologous structures.
Homology that evolved before the common ancestor of a set of speciesand which is present in other species outside that set of species.Human evolution, the process by which human beings developed on Earth from now-extinct attheheels.com zoologically, we humans are Homo sapiens, a culture-bearing, upright-walking species that lives on the ground and very likely first evolved in Africa about , years attheheels.com are now the only living members of what many zoologists refer to as the human tribe, Hominini, but there is .
acquired trait: A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation (for example, the large.
Early African Homo erectus fossils (sometimes called Homo ergaster) are the oldest known early humans to have possessed modern human-like body proportions with relatively elongated legs and shorter arms compared to the size of the attheheels.com features are considered adaptations to a life lived on the ground, indicating the loss of earlier tree-climbing adaptations, with the ability to walk and.
attheheels.com: Human Locomotion: The Conservative Management of Gait Related Disorders (): Thomas Michaud: Books. Since graduating from Western States Chiropractic College in , Dr. Michaud has published numerous book chapters and journal articles on a variety of subjects ranging from biomechanics of the first metatarsophalangeal joint and shoulder, to the pathomechanics and management of .
Evolution. Gracile australopiths shared several traits with modern apes and humans, and were widespread throughout Eastern and Northern Africa around million years ago.
The earliest evidence of fundamentally bipedal hominids can be observed at the site of Laetoli in attheheels.com site contains hominid footprints that are remarkably similar to .