AP BIO CH 22

adaptations

-inherited characteristics of organisms that enhance their survival and reproduction in specific environments -adaptation to environment and origin of species similar processes -finch beaks

catastrophism

-principle that events in the past occurred suddenly and were caused by mechanisms different from those operating today developed by Cuvier -the boundary between each layer of strata represent a different catastrophe

uniformitarianism

-principle that mechanisms of change are constant over time developed by Hutton and Lyell -profound change could take place through the cumulative effect of slow but continuous processes

natural selection

-process in which organisms that have certain inherited traits tend to survive and reproduce at higher rates than others because of those traits -over time the match between organisms and their environment increases -adaptations and sometimes new species arise if an environment changes or species moves to a new environment

fossils

-remains/traces of organisms from the past -found in layers of sedimentary rock that make up strata -provide a glimpse of organisms that lived on earth at the time the layer was formed -paleontology developed by George Cuvier

artificial selection

-selective breeding of plants and animals by humans to encourage the occurrence of desired traits

homology

-similarity resulting from common ancestry -homologous structures - represent variations on a structural theme present in a common ancestor; mammalian forelimbs -vestigial structures - remnants of features that served important functions in an organism's ancestors; pelvis and leg bones of snakes and whales, eyes of cave fishes -universal DNA and RNA -evolutionary tree - diagram that reflects evolutionary relationships among groups of organisms

evidence of evolution in organisms

-soapberry bug beaks -finches -drug-resistant bacteria -homologous and vestigial structures -pesticide resistance in insects -sunflowers, mules, snails' shells

Name three scientists that contributed to Darwin's work and explain specifically their contributions.

1. Georges Cuvier- older fossils are more dissimilar to current life forms; from each layer to the next some new species appeared while some disappeared 2. James Hutton- proposed that Earth's geologic features could be explained by gradual mechanisms still operating today 3. Charles Lyell- developed his idea of uniformitarianism, which stated that mechanisms of change are constant over time 4. Jean-Bapiste de Lamarck- theories of use and disuse, and inheritance of acquired characteristics, which gave way to Darwin's evolutionary theories

Name two concepts that can account for the variability of life.

Descent with modification explains how certain traits become more common in a species over time. The progeny of a generation will have different traits than that of the previous generation depending on which traits allow the organism to lead the healthiest and longest life possible. In addition, the process of Natural Selection can account for the variability of life because the most common and favorable traits for an organism to possess can vary based on food sources or environment.

Summarize Lamarck's hypothesis of evolution.

Lamarck hypothesized that organisms adapt by acquiring traits and that organisms with parts of the body that are used frequently become stronger and better and parts of the body that are not used eventually deteriorate. This first principle was called use and disuse. Lamarck's second principle is the principle of inheritance of acquired characteristics. This states that organisms could pass these characteristics to their offspring.

How does the concept of descent with modification explain both the unity and diversity of life?

Organisms share characteristics because they share common ancestors; the great diversity of life occurs because new species have repeatedly formed when descendant organisms gradually adapted to different environments, becoming different from their ancestors.

How have drug resistant bacteria evolved?

With the introduction of antibiotics, some individual bacteria within a population will be resistant to antibiotics like penicillin. These bacteria can share their genes with members of their species and other species which will then cause, through natural selection of the resistant individuals, a population to become resistant. Antibiotics such as methicillin that block an enzyme used to support the cell wall can be overcome when bacteria use a different protein to create their cell walls. These bacteria that survive will pass on their genes to their offspring which will create a population that is resistant to now not only penicillin, but also methicillin.

convergent evolution

-independent evolution of similar features in different lineages -marsupials and eutherians -analogous structures - features that share a similar function, but not common ancestry

evolution

-descent with modification -a change in the genetic composition of a population generation to generation -all organisms today are evolved from common ancestors -pattern of evolution - evidence, revealed by data: biology, geology, physics, and chemistry -process of evolution - natural selection, mechanisms that produce the observed pattern of change -the unity of life, the diversity of life, and the match between organisms and their environments -individuals do not evolve, a population does -Aristotle - scala naturae, organisms are organized from least to most complex

biogeography

-geographic distribution of species -continental drift and the fossil record; endemic species on islands

Using examples and descriptions, describe relationships demonstrating homologous structures and convergent evolution, and give an example to define a vestigial structure.

1. Homologous structures are structures in different species that are similar because of common ancestry. Examples of these types of structures are the similar bone structures of the human arm and the cat leg, and also the fin of a whale and the wing of a bat. Even though these structures have been adapted for different functions, the forelimbs of all mammal are constructed from the same skeletal elements. 2. Convergent evolution is the evolution of similar feature in different lineages. For example, marsupial mammals are distinct from another group of mammals (the eutherians); however, eutherians complete their embryonic development in the uterus, whereas marsupials are born as embryos and complete their development in an external pouch. 3. Vestigial structures are remnants of features that were once useful to the ancestors of a species, but have little or no practical use anymore. Examples of this are the human appendix, which used to be an additional cleanser of toxins, now does not have a function; the hind limbs of a whale were useful when it lived on land, but it no longer has legs or a need to walk; some snakes have pelvises that are no longer necessary; some species of blind, cave-dwelling animals have vestigial eyes buried under scales.

What are four pieces of evidence that support Darwin's theory about evolution? Briefly explain each and how they support evolution.

1. Natural selection is the process in which individuals that have certain heritable traits better suited to the environment tend to survive and reproduce at higher rates than those who don't. It contributes to how organisms evolve, for those with better traits for their environments will become more plentiful in number. Those organisms with less desired traits will decrease in population. 2. Homology refers to similar anatomical structures among different organisms although they may carry different functions. These structures point to a common ancestor among these organism and support evolution among these species. 3. Fossil Record shows past and extinct organisms which can be compared to present-day species. It shows evidence for evolution by documenting the distinct change in organisms throughout history. 4. Biogeography is the geographic distribution of species throughout the world. It explains how the same fossils can be found on two different continents or why aquatic fossils can be found at the top of a mountain. It supports evolution by illustrating how the world changed causing organisms to evolve.

Lamarck's hypothesis

1. use and disuse - parts of the body that are used extensively become larger and stronger, while those that are not used deteriorate 2. inheritance of acquired characteristics - an organism could pass on these modifications to offspring

Name the five main ideas of Darwin's theory of natural selection.

Variation exists in populations. The overproduction of offspring results in more offspring than the environment can support. In an environment, there is competition among organisms for food, mates, nesting sites, and escaping predators. There is differential survival, in which those with the most successful traits/adaptations survive to pass on their traits. There is also differential reproduction through which adaptations become more common in population.