Evolution

Variation in the organisms under selection. In both artificial selection and natural selection there must be heritable variations that have the possibility of being in the case of artificial selection what the selector wants in the organism and in thje case of natural selection survivability and reproductive advantages.

Take the cytochrome C electron shuttle in the electron transport chain and see how it is highly conserved in form and function among a wide variety of eukaryotes. That is molecular evidence for the relatedness of widely disparate organisms.

When the mean value of variation is selected, it typically results in stabilizing selection. This type of selection favors individuals with traits that are close to the average, reducing the prevalence of extreme phenotypes. As a result, the population tends to maintain its average traits over time, leading to reduced variation and increased uniformity within the population.

This theoretical question has highly differing answers. Some archaeologists may argue that the modern human species evolved around 2.3 million years ago, while others believe differently.

Microevolution is small evolutionary changes. Macroevolution is change above the specie level. Biologists debate if this process even exists. Some say they are fundamentally the same thing. It seems that macroevolution is the evolution of evolution. That sounds complicated.

1. Variation: Individuals within a species exhibit variation in traits.
2. Competition: Resources are limited, leading to competition for survival.
3. Survival of the fittest: Individuals with advantageous traits are more likely to survive and reproduce.
4. Heritability: Traits that confer a survival advantage are passed on to offspring.
5. Gradual change: Over time, the population evolves as advantageous traits become more common.

Yes, gradualism is a concept that suggests change happens slowly and steadily over time, without sudden shifts or abrupt changes. It refers to a continuous process of evolution or transformation.

This is called genetic divergence. Over time, accumulated genetic differences between populations can lead to the formation of new species through a process known as speciation. This can occur through various mechanisms such as natural selection, genetic drift, and isolation.

Sexual selection is a subset of natural selection that is strictly " concerned " with reproductive success. You will see organisms adapted in physiology and behavior to attract mates of the other sex with these adaptions contravening survival possibilities. Take the classic peacock example. The peacock is selected by the peahen on the basis of his tail display regardless of how such a heavy and survival risking adaption leaves the peacock open to predation. Remember, fitness is reproductive fitness and if the peacock can father most of the progeny of his local population at mating time because his tail attracts more females then what matter if he dies young.

Yes, evolution refers to the process by which organisms change over successive generations through genetic variation and natural selection. This change can occur gradually over long periods of time, leading to the diversity of life on Earth today.

To determine if evolution by natural selection is occurring in a cactus population, you would need to observe changes in the heritable traits of the cacti over time, caused by differences in survival and reproduction. This would indicate that certain traits are being favored, leading to a shift in the genetic makeup of the population.

Yes, when distantly related life forms independently evolve similar traits to adapt to similar environmental pressures, it is called convergent evolution. This phenomenon demonstrates the power of natural selection in shaping organisms to their environments.

They think that the first algae developed as a result of endosymbiosis between primitive eukaryotic cells and cyanobacteria. A similar phenomenon can be seen in amoebae of the species Paulinella chromatophora, with which modern cyanobacteria have formed an endosymbiotic relationship.

Spores allowed plants to reproduce and disperse in a dry environment, enabling them to colonize land. Spores served as a protective mechanism against desiccation and helped plants survive in diverse habitats. This adaptation was essential for the transition of plants from aquatic to terrestrial environments.

Natural selection is the differential reproductive success of genomic variation. But for differing variants to be able to compete reproductively, such variants must exist in the first place. Reproduction causes such variants to come into existence.

Lamarck's theory of evolution, known as Lamarckism, proposed that organisms could pass on traits acquired during their lifetime to their offspring, such as a giraffe stretching its neck to reach higher leaves and then having offspring with longer necks. This idea was incorrect because it lacks genetic basis; traits are inherited through genes, not acquired characteristics. Modern genetics and Darwinian natural selection provide a more robust explanation for evolution, emphasizing heritable variations that arise through mutations rather than acquired traits.

Artificial selection, the process by which humans select certain traits in organisms to breed, mimics natural selection by showing that organisms can be changed through selective pressures. It demonstrates that organisms have the potential for variation in traits that can be passed on to offspring, supporting the idea that natural selection in the wild can lead to evolutionary change over time.

The evidence for evolution suggests that all living things are related through common ancestry, and that populations of organisms change over time in response to their environment. This is supported by fossil records, comparative anatomy, embryology, and molecular biology.

Answer 1

Hard to answer as this is not settled in evolutionary biology. Some call this the " green beard effect, " where one organism's kin recognizes the organism by some physiological marker that is reflective of the genetic relatedness. Still, the evidence for this concept is rather thin, so we do not know if we are seeing such an effect, or one is just seeing the result of organisms being raised in close proximity.

Answer 2

There are various ways for genes to affect the recognition of kin. For instance, genes may affect pheromone production, giving the family member a recognizable scent. Genes might affect fur patterning, or bird-song. Certainly humans are often able to distinguish relatives by their facial features, even if they had not met these relatives before.

Note that there is much still to be learned about the role of such genes in kin altruism, and that the mechanisms of kin altruism may not even need to rely on such outward markers. The subjects of kin recognition and kin altruism should, to some extent, be studied individually.

Gene flow, or the movement of genes between populations, can introduce new genetic variation into a population. This can increase genetic diversity and lead to the spread of beneficial traits, which can drive evolutionary changes within a population over time. In essence, gene flow promotes adaptation and can result in the evolution of populations.

There is no such reason.

Evolution, the change in allele frequency over time in a population of organisms, is a fact and as much a fact as the sun rising in the East every day.

The theory of evolution explains much about the fact of evolution and is supported by more evidence that the fact that the sun seems to rise in the East is explained by the theory of heliocenterism.

Darwin's Theory of Evolution consists of three main parts: variation, inheritance, and selection. Variation refers to differences in traits among individuals, inheritance involves passing on these traits to offspring, and selection entails the process by which certain traits become more common in a population due to their advantage in survival and reproduction.

Carrying capacity refers to the maximum population size an environment can support. As resources become limited due to exceeding carrying capacity, organisms must adapt or evolve in order to survive and reproduce. Evolution may favor traits that improve resource acquisition, utilization, or competition to better match the available resources in a given environment.