Evolution

Genetic drift is the spread of specific random variations throughout the gene pool in the absence of specific selection pressures. There's always random variation in the population, but there aren't always changes in the environment for the population to adapt to. So natural selection, in stead of moving the population towards adaptation, might select from that random variation to move 'sideways', as it were, to a state that's equally well-adapted to the environment as what came before, but different. As random variation may produce many variants that are, more or less, equally well-adapted to their environment, the direction of evolution that results is more or less random. Because variations may spread throughout small populations faster than throughout large populations, and because a large gene pool has a stabilizing effect on the spread of variations, small populations drift faster than large populations.

Evolution can occur at different rates depending on various factors such as the generation time of the organism, environmental pressures, and genetic variability. In some cases, evolution can be slow, taking thousands to millions of years for noticeable changes to occur. In other cases, evolution can happen relatively quickly, especially when organisms face changes in their environment that require rapid adaptation.

Scientists who study evolution are called evolutionary biologists. They research the processes of genetic change and natural selection that drive the diversity of life on Earth.

A gene pool includes all the genes, or variations of genes, within a population of organisms. This genetic diversity is crucial for adaptation and evolutionary processes. The gene pool is dynamic and can change due to factors like mutation, genetic drift, gene flow, and natural selection.

Embryology is used in evolution because its shows a common ansetor. For example, a human and fi sh have similar embryos. Both embryos have pharyngeal slits. In a fish those develop into gills. In humans those turn into our ears.

The process of natural selection and evolution can vary in terms of the time it takes, ranging from hundreds to millions of years depending on the species and environmental factors. Evolution is a gradual process that occurs over generations as populations adapt to their changing surroundings through natural selection.

Natural selection primarily affects individuals within a population. Over time, as certain traits offer a survival advantage, those individuals will be more likely to survive and reproduce, passing on these advantageous traits to their offspring. This process can lead to changes in the population as a whole.

The presence of a dominant allele is not always required to explain common traits in a population. Polygenic inheritance, where multiple genes contribute to a trait, can lead to common traits without a dominant allele. Additionally, environmental factors can also play a significant role in shaping common traits among a population.

" Survival of the fittest " is an inaccurate phrase coined by one Herbert Spencer, though Darwin did use this phrase in later edition of The Origin. The theory of evolution by natural selection showed how the " fit " survive and, more importantly, achieve reproductive success.

Tell your teacher to stop using this phrase!

Genetic drift is the spread of specific random variations throughout the gene pool in the absence of specific selection pressures. There's always random variation in the population, but there aren't always changes in the environment for the population to adapt to. So natural selection, in stead of moving the population towards adaptation, might select from that random variation to move 'sideways', as it were, to a state that's equally well-adapted to the environment as what came before, but different. As random variation may produce many variants that are, more or less, equally well-adapted to their environment, the direction of evolution that results is more or less random. Because variations may spread throughout small populations faster than throughout large populations, and because a large gene pool has a stabilizing effect on the spread of variations, small populations drift faster than large populations.

I study evolution because it is the concept that underlies all of biology. Biology would still be natural history without the fact of evolution and the theory of evolution by natural selection is the overarching theory that underpins all of biology while explaining much about the fact of evolution.

" Nothing in biology makes sense, except in the light of evolution. " Dobzansky.

PTA should be punctuated with periods as an abbreviation for Parent-Teacher Association.

The most significant physical component of the theory of evolution is the concept of natural selection. Natural selection is the process by which organisms with advantageous traits for survival and reproduction are more likely to pass on their genes to the next generation, leading to the gradual change of species over time.

You can find the answers to the NY State lab "Relationships and Biodiversity" in the teacher's manual that accompanies the lab or by searching for answer keys online. It's important to use these resources responsibly and make sure you understand the concepts before relying solely on the answers.

The primary adaptation of an arthropod is not the jointed appendage, funnily enough it's what covers the rest of it.

Chiten, the hard exoskeleton of arthropods allowed them to evolve in millions of different shapes and forms, while at the same time providing a protective armour casing.

Ever wonder why the insect life was not affeced by Chernobyll, or why a crayfish doesn't cook in a microwave? The exoskeleton in Arthropods is the key to their success - they, along with other invertebrates, take up 75% of all life on the planet.

They are less complex and their genomes are easily manipulated. The plasmids in bacteria provide an oppertunity for simple genetic recombination exercises. Bacteria can be easily made to be lab dependent so that if an accidental release occured there would be no contamination because the bacteria can not live outside the lab environment.

Hugo de Vries is the one who proposed theory of mutation . He said 'Mutation are discontinuous variations. These are due to changes in chromosomes, genes and DNA and may or may not be inherited.'.

Stabilizing selection typically results in less genetic diversity because it selects against extreme phenotypes, narrowing the range of traits present in a population. This leads to the preservation of intermediate phenotypes that are favored by the selective pressures, reducing overall genetic variation.

Both gradualism and punctuated equilibrium are theories of evolution that describe the pace at which species evolve over time. Both theories acknowledge that evolution occurs, albeit at different rates. Gradualism posits slow, continuous changes over long periods, while punctuated equilibrium suggests that long periods of stability are punctuated by sudden bursts of rapid change. Both theories emphasize the importance of natural selection in driving evolution.

Darwin collected thousands of specimens across the world. Like other naturalists before him, Darwin noted similarities in the species that contributed to their classification. But Darwin also had fossils detailing changes that had occurred over vast stretches of time.

Darwin noted pigeon breeders could introduce stable changes in a population via a process of artificial selection. He also saw that nature introduced its own changes in species. Although there is a huge diversity of life, Darwin saw how it was organized and how it must have changed over the ages. Not long after he published his theory, a fossil of Archeopteryx was discovered, showing the link between birds and dinosaurs. Later fossils of Neandertal were discovered, demonstrating the existence of multiple hominid species in prehistoric ages past.

A population can change over time due to factors like birth rate, death rate, immigration, and emigration. High birth rates can lead to population growth, while high death rates can lead to a decline. Immigration can increase the population, while emigration can decrease it. Environmental factors, public health policies, and socio-economic conditions can also impact population changes.

Evolution is the process by which living organisms change over time in response to their environment, leading to the emergence of new species and the extinction of others. It affects all living organisms by driving genetic diversity, adaptation to changing conditions, and the development of new traits that enhance survival and reproduction. Through evolution, organisms become better suited to their environments, ultimately contributing to the diversity of life on Earth.

Fitness to a biologist means ' reproductive fitness. ' The variant organism that survives against the immediate environment and leaves more descendants that the other organisms of his population is fit. These descendant's this organism leaves change the allele frequency of the populations gene pool and this is the definition of evolution.