Master Evolution Terms and Questions

How does mutation help organisms evolve?

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What does comparative embryology mean?

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What is the half-life of carbon 14?

5730

Species

A group of organisms that can mate And produce fertile offspring.

half life

A half-life is the amount of time needed for half of an isotope to decay. This point occurs at 5730 years for carbon-14, as indicated by the line on this graph.

Stabilizing Selection

A population of arboreal rodents lives in one species of pine tree. These pine trees have very evenly spaced branches of uniform thickness. Rodents that are too small cannot reach between the branches to move around in the tree. Rodents that are too big and heavy break through the branches and fall out of the trees. The rodent population contains adults of very uniform size. What type of selection has created this uniform size distribution in these rodents?

Batesian Mimicry

Batesian mimicry is a form of mimicry typified by a situation where a harmless species has evolved to imitate the warning signals of a harmful species directed at a common predator.

Darwin referred to the process of promoting certain traits by breeding members with those traits as ____.

Darwin observed what he called artificial selection in pigeon breeding. The breeders would select pigeons with desirable traits, in order to pass those traits to offspring.

Hardy-Weinberg equilibrium

Few natural populations ever experience Hardy-Weinberg equilibrium, though, since large populations are rarely found in isolation, all populations experience some level of mutation, and natural selection simply cannot be avoided.

What does the survival of the fittest mean?

Natural selection conceived of as a struggle for life in which only those organisms best adapted to existing conditions are able to survive and reproduce.

Divergent Evolution

Occurs when a group from a specific population develops into a new species. In order to adapt to various environmental conditions, the two groups develop into distinct species due to differences in the demands driven by the environmental circumstances. A good example of how divergent evolution occurs is in comparing how a human foot evolved to be very different from a monkey's foot, despite their common primate ancestry. Read more: Divergent Evolution - Species, Fox, Evolve, Differences, Population, and Similar http://science.jrank.org/pages/2609/Evolution-Divergent.html#ixzz1JWwKXfxJ

Darwin

On the Origin of Species

paleontologist

Paleontologists study fossil records of many organisms. They develop theories about the lives of once-living organisms, and the characteristics of earth during the time those organisms lived.

Hardy-Weinberg Principle

States that a sexually reproducing population will have stable allelic frequencies and therefore will not undergo evolution, given the following five conditions:large population size, no immigration or emigration, random mating, random reproductive success, no mutation

Common Descent

The belief that all present life evolved from a few common ancestors.

Fitness

The probability that an individual will contribute its genes to the next generation.

What is carbon-14 dating used for?

To date materials less than 60,000 years old

Vestigal Structure

Vestigiality describes homologous characters of organisms that have seemingly lost all or most of their original function in a species through evolution. Appendix... etc.

Who is Lamarck?

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Lamarck's Hypothesis: The Inheritance of Acquired Characteristics

1. Use and disuse: described how body parts of organisms can develop with increased usage while unused parts weaken. This idea is correct, as is commonly observed among athletes who train for competitions. 2. Inheritance of Acquired Characteristics: Those characteristics developed ("acquired") by individuals are somehow passed on to their offspring, who can continue that development... This idea was incorrect as only changes in genetic material can be passed on to offspring. 3. Natural transformation of Species: described how organisms produced offspring with changes, transforming each subsequent generation into a slightly different form toward some ultimate, higher order of complexity. Species did not become extinct nor did they split and change into two or more species. This idea was also incorrect. Although Lamarck's theories have been discredited, Lamarck still deserves credit for recognizing that organisms interact with their environment and experience through evolutionary change and for proposing a testable mechanism for this change

200 g sample of lawrencium is left in a container from 8:00 AM one morning until 2:00 PM the next afternoon. If the mass of the sample of lawrencium was 25 g, what is the half-life of lawrencium??

10 hours

Population decline causes an extreme genetic drift called a ____.

A bottleneck is an extreme example of genetic drift that occurs when a population experiences large declines and then rebounds. Genetic drift refers to the changes in the frequencies of alleles in a population due to chance. Inbreeding and reduced diversity is seen when a bottleneck occurs in a population.

What is an Adaptation?

A change in genetic code to suit a certain environment.

Müllerian mimicry

A form of biological resemblance in which two or more unrelated noxious, or dangerous, organisms exhibit closely similar warning systems, such as the same pattern of bright colours. According to the widely accepted theory advanced in 1878 by the German naturalist Fritz Müller

Directional selection

A group of early giraffes lives in a lush forest with many trees and shrubs of different heights to feed on. These giraffes have necks of various lengths, with most giraffes having a medium length neck. Then a blight passed through the area, killing off all of the low growing plants, leaving only tall trees whose leaves are far off the ground. Giraffes with shorter necks now have a hard time getting food, while those with longer necks can feed on the high-growing leaves. After several generations, the giraffes in this area all have longer necks than those before the blight. What type of selection has occurred in this giraffe population?

Disruptive selection

A population of finches lives on an island with an abundant food supply. These finches have highly variable beak lengths, allowing them to feed on different types of food. Then several other species of birds move into the area, making food supplies scarce. The only types of food left for the finches are small seeds and nectar from long tubular flowers. Finches with small beaks can easily grasp and crack the seeds. Finches with long beaks can reach inside the long flowers to reach the nectar. However, some finches have beaks that are too large to deal with the small seeds, but too small to reach inside the flowers. After several generations, there are two populations of finches: those with short beaks and those with long beaks. What kind of selection has acted on these finches?

polymorphic

A trait that exists in several different morphs

What are two types of carbon?

Carbon-14: Decays over time Carbon-12: Does not decay

Stablization Selection

Decrease in Variation. When selective pressures select against the two extremes of a trait, the population experiences stabilization. For example, plant height might be acted on by stabilizing selection. A plant that is too short may not be able to compete with other plants for sunlight. However, extremely tall plants may be more susceptible to wind damage. Combined, these two selection pressures select to maintain plants of medium height. The number of plants of medium height will increase while the numbers of short and tall plants will decrease.

How can embryology help in the study of evolutionary relationships?

During the course of development, the embryo passes through stages in which it resembles its ancestors. For example, human embryos have a tail at some stages, like those of our primate ancestors.

Disruptive Selection

Elimination of Middle. Selection pressures act against individuals in the middle of the trait distribution. The result is a bimodal, or two-peaked, curve in which the two extremes of the curve create their own smaller curves. For example, imagine a plant of extremely variable height that is pollinated by three different pollinators, one that was attracted to short plants, another that preferred plants of medium height and a third that visited only the tallest plants. If the pollinator that preferred plants of medium height disappeared from an area, medium height plants would be selected against and the population would tend toward both short and tall, but not medium height plants. Such a population, in which multiple distinct forms or morphs exist is said to be polymorphic.

Directional Selection

Elimination. One extreme of the trait distribution experiences selection against it. The result is that the population's trait distribution shifts toward the other extreme. In the case of such selection, the mean of the population graph shifts. Using the familiar example of giraffe necks, there was a selection pressure against short necks, since individuals with short necks could not reach as many leaves on which to feed. As a result, the distribution of neck length shifted to favor individuals with long necks

Evolution

Evolution is the change over time in one or more inherited traits found in populations of organisms. Inherited traits are particular distinguishing characteristics, including anatomical, biochemical or behavioural characteristics, that are passed on from one generation to the next. Phenotypic expressions of these traits can be influenced by gene-environment interactions. Evolution may occur when there is variation of inherited traits within a population. The major sources of such variation are mutation, genetic recombination and gene flow.

Darwin's Hypothesis: Natural Selection

Fifty years after Lamarck published his ideas, Darwin published The Origin of Species, Darwin's theory that natural selection, or "survival of the fittest," was the driving force of evolution. 1. Overproduction: More offspring are produced than will ultimately survive and reproduce 2. Variation: Inheritable features vary from individual to individual. 3. Change in environment: Changes in climate, topography, food supply, predators, etc. 4. "Struggle for existence": Mainly competition within the species, for food, habitat, survival from being eaten 5. "Survival of the fit" (not necessarily the strongest): Those with more adaptive traits tend to survive longer and/or produce the most offspring; these are the "naturally selected". 6. Inheritance of "selected" features: Traits involved are already inheritable, but may involve new combinations. 7. New Species better adapted to the new environment: When the collective traits of the population differ significantly from the earlier population and when they can no longer reproduce with the earlier population.

What are the five evidences for evolutionary theory?

Fossils Comparative biochemistry Homologous structure Analogous structure Vestigal structure

Fossils

Fossils provide evidence of once-living species. Animals, plants, and some bacteria can form fossils. Only a small percentage of extinct organisms have formed fossils.

29 000 years old

If it was determined that a fossil contained a little over 3% of the original amount of carbon-14 it once was composed of, what would be an approximate age for the fossil?

Principle of Acquired Characteristics

Inheritance of acquired characters is the once widely accepted idea that physiological modifications acquired by an organism can be inherited by the offspring. Acquired characteristics (or characters) are those changes in the structure or function of an organism that are the result of use, disuse, environmental influences, disease, mutilation, and so forth, such as a muscle that is enlarged through use or mice that have their tails cut off. The theory of the inheritance of acquired characteristics, or "soft inheritance," holds that an organism experiencing such a modification can transmit such a character to its offspring.

A morphological adaptation in which one species resembles another is called ____.

Mimicry. Some animals can assure better survival by mimicking other species in order to gain protection from predators. This resemblance is called mimicry.

Normal Population Range

Natural selection can take many forms. To make talking about this easier, we will consider the distribution of traits across a population in graphical form. In we see the normal bell curve of trait distribution. For example, if we were talking about height as a trait, we would see that without any selection pressure on this trait, the heights of individuals in a population would vary, with most individuals being of an average height and fewer being extremely short or extremely tall. However, when selection pressures act on a trait, this distribution can be altered.

In what type of rock will you find fossils?

Sedimentary

homologous structures

Similar structures descending from the same ancestor with different functions

Sexual Selection

The selection of traits based on their role in courtship and mating.

Natural Selection

The theory holding that competition exists within species, determining which species live to have offspring, and pass their traits on to those offspring.

Darwinism

The theory of evolution proposed by Charles Darwin. It holds that species change over time and that this change comes about through the mechanism of natural selection.

The wings of birds and insects are considered what kind of structures?

These are analogous structures, because they are morphologically similar but arose from entirely different ancestral structures

Where did Darwin travel and what did he observe?

Traveled to the Galapagos Islands, birds of the same species had different types of beaks.

How did the views of Jean-Baptiste de Lamarck differ from those of Darwin?

Under Lamarckian evolution, internal forces drive individual organisms to improve in their fit to the environment.

What are two main components of natural selection?

Variation and inheritance are two main components of natural selection, along with limited offspring and passing traits that result in reproductive success.

Smooth bell-shaped curve.

What type of distribution graph would you expect for a trait on which there is no selection pressure?

The mean of the curve should shift up or down the scale, depending on the direction of selection.

What type of distribution graph would you expect on which there is directional selection pressure?

The curve should be narrower, but with the same mean.

What type of distribution graph would you expect on which there is disruptive selection pressure? Directional selection pressure?

The curve should be bimodal (have two peaks).

What type of distribution graph would you expect on which there is stabilization selection pressure?

Convergent Evolution

When organisms that aren't closely related evolve similar traits as they both adapt to similar environments. There are a finite number of effective solutions to some challenges, and some of them emerge independently again and again. In the frigid waters of the ocean surrounding Antarctica, fish have a special trait which allows them to survive the big chill. As scientists discovered in the 1960s, the fish have adapted by evolving a kind of antifreeze. It's composed of molecules called glycoproteins that circulate in the blood of the fishes, slightly lowering the temperature at which their body fluids would otherwise freeze and kill them. The glycoproteins surround tiny ice crystals and keep them from growing. It's another of those ingenious evolutionary solutions that seem almost too clever to be true. But consider this: Nature did it not once, but at least twice. Fish at the other end of Earth, in the Arctic, also have antifreeze proteins. But those two populations of fish split long before they developed the antifreeze genes and proteins. And, researchers have found, the genes that produce the antifreeze proteins, north and south, are quite different. This is evidence that quite separate, independent episodes of molecular evolution occurred, with the same functional results

Comparative Embryology

The less similiar you are at the beginning of development the less you have in common

A naturalist cataloging species in a remote forest discovers two different varieties of beetles. Both have a large horn-like structure on their heads that they use to dig into the ground to find food, but they are otherwise not very similar. What conclusions can the naturalist draw from this comparison of traits?

The naturalist cannot draw any definite conclusions from this comparison. While both beetles have similar horn-like structures that they use in the same way, simple comparison does not show if these beetles received this trait from a common ancestor or if two different lineages of beetles evolved a similar trait independently.