The Dung of the Devil- from 1818 to 1920, the world experienced a flu out break on a unprecedented scale. During the height of the outbreak reports stated that people in china had found the root of a plant that was beneficial in fighting the flu. The plant (Ferula assafoetida) had a foul smell that inspired the plants common name, the Dung of the Devil. when the worldwide swine flu broke out in 2009-2010 scientists recalled people using the plant and decided to explore its potential to combat the H1N1 flu. They found that the plant had strong antiviral properties, and that the plant had the potential to produce new pharmaceutical drugs to fight the H1N1 flu. This led scientist to look at organisms to produce other life saving drugs, such as willow trees the original source of salicylic acid which is used in aspirin and rosy periwinkle which is used to treat childhood leukemia and Hodgkin's disease. Many species that are known or are suspected sources of drugs are being lost to deforestation, agriculture, and other human activities. Only a small fraction of the millions of species have been screened for useful drugs which makes a convincing argument for conserving earths biodiversity.
5.1 Biodiversity and how it is measured- a ecosystem is a particular location on earth with interacting biotic and abiotic factors, a species is a group of organisms that is distinct from others groups in terms of size, shape, behavior, or biochemical properties that can be interbred and produce viable offspring. Genetic diversity is the measure of genetic variation among individuals in a population. Current estimates say there is between 5 million to 100 million species, but most scientists believe there are about 10 million species.
Species richness is the number of species in a given area and is used to give an approximate sense of the biodiversity, and Species evenness is the relative portion of individuals within the different species in a given area, which tells us if an area is dominated by one species or if all species have a similar abundance. An example of high richness and low evenness would be a ecosystem with predominantly on type of tree, lets say oak. High richness and low evenness would be a ecosystem with lots of trees, but also a abundance of species 4 oak, 4 pine etc. Low richness would be an ecosystem with few trees lets say 100, but had 25 oak, 25 pine, 25 bamboo, and 25 redwood.
Scientists use phylogenies to indicate how closely related species are to one another. The branching pattern of evolutionary relationships is called a phylogeny. The relatedness is determined by similarity of traits, the more similar traits, the most closely related the two species are assumed to be.
5.2 describe the ways in which evolution occurs- earths biodiversity is the product of evolution which is the change in the genetic composition of a population over time. However it can occur at multiple levels. Evolution below the species level, such as the evolution of different varieties of apples or potatoes is known as microevolution. In contrast evolution that gives rise to new species, genera, families, classes, or phyla is known as macroevolution. Ex giraffes developing longer necks to survive. A mutation is a random change in genetic code produced by a mistake in the copying code. Environmental factors such as the sun can also cause mutations, and mutations can be passed on through the generations. They can affect offspring in many ways in either a positive or negative way. such as giraffes developing longer necks to reach higher leaves and a negative being a mutation in color that makes them stand out to predators.
Genotype is the complete set of genes in an individual ex.genes that code for eye color, and phenotype is a set of traits expressed by an individual ex. the color of your eyes. In some cases the phenotype is determined almost entirely by genes. For instance if a person who inherits genes for brown eyes will haqve brown eyes regardless of where they live. However most are the product of the individuals environment as well as its genotype ex. crocodile gender depends on the temperature of the eggs during incubation determines the gender.
Evolution by artificial selection is the process in which humans determine which individuals to breed, typically with a preconceived set of traits in mind. For instance the domestication of the dog, the diversity of domesticated dog breeds is a result of artificial selection in wolves. Another example is when scientists started with a single species of wild mustard, and produced a variety of food crops including cabbage, cauliflower, broccoli, Brussels and so forth. A final example is due to increased use of weed killers roundup resistant weeds have formed.
Evolution by natural selection is the process of which the environment determines which individuals survive and reproduce. The idea of natural selection became synthesized due to two scientists, the more prevalently known Charles Darwin had 5 key concepts. 1-individuals produce an excess of offspring. 2-not all offspring survive. 3-individuals differ in there traits. 4-differences in traits can be passed on from parents to the offspring. 5-differences in traits are associated with differences in the ability to survive and reproduce.
Fitness is the individuals ability to survive and reproduce, and adaptations are a trait that improve the individuals fitness. They relate to each other because adaptations help increase the fitness of the individual. In one instance plants in a desert plants adapted large tap roots to draw water from deep in the soil, which allowed them to survive and reproduce in the desert environment.
Evolution can also occur in a third, random and nonadaptive processes. The genetic composition changes over time, but the changes are not related to differences in the fitness among individuals. mutations adds to the genetic variation, genetic drift affects evolution because it changes the composition of population over time as a result of random mating, and the bottleneck affects it because it reduces the genetic diversity of a population cuased by a reduction of size. The founder effect changes the genetic composition of a population as a result of descending from a small number of colonizing individuals.
5.3 explain how environmental changes affects speciation and extinction- geographic isolation is physical separation of a group of individuals form others of the same species ex. a large river may change its course and divide a large prairie into two halves. If the separated habitats differ in environmental conditions, natural selection will favor different phenotypes in each of the habitats. Reproductive isolation is the result of two populations within a species evolving separately to the point that they can no longer interbreed and produce viable offspring. Allopatric speciation occurs with geographical isolation. Sympatric isolation is the evolution of one species into two, without geographic isolation, polyploidy plays a role in it. in polyploidy thenumber of chromosomes may increase to three, four, or sometimes even six sets. once organisms are polyploidy they cannot breed with diploid ancestors who only have one chromosome. When polyploidy occurs they are reproductively isolated and therefore 2 different species.
The pace of evolution depends on several factors. Significant changes to an organism may take hundreds to millions of year. If the pace of evolution is slow, which can be caused by long generation times or when a population contains low genetic variation, the species wont be able to keep up with the rate of environmental changes the species may go extinct.
Genetically modified organisms is a organism produced by copying genes form a species with a desirable trait and inserting them into another species. Scientists choose desirable traits such as rapid growth or disease resistance and put them into a different species of plants, animals, or microbes. One example is when scientists found that soil bacterium naturally produces its own insecticide. Plant breeders then identified the bacterial genes that are responsible for making the insecticides and copied the genes and inserted them into crop plants. Now the crops can produce there own insecticide, some examples are Bt-corn and Bt-cotton.
5.4 explain the concept of an ecological niche- all species have a range of tolerance, or limits to the abiotic conditions they can tolerate such as temperature or humidity. The fundamental niche is the suite of abiotic conditions the species can survive, grow , and reproduce, opposed to the realized niche which is the range of biotic and abiotic conditions the species can live in.
key conditions of niche generalists is there ability to feed on numerous things and live in different habitats, niche specialists live in very narrow ranges of conditions and only feed on certain species
Environmental changes such as the temperature warming caused trees to move north. As temperatures warmed following the retreat of glaciers, trees moved north
Three reasons a species may go extinct are there may be no favorable environment close enough to which they can move. ex a species cant move and survive if there is no where else with conditions where it can survive. Another reason is even if there is a place for it to move it may already be occupied. Finally environmental change may happen so rapidly that species do not have time to evolve new adaptations.
A mass extinction is a large extinction of species in a relatively short period of time, and the earth has experienced 5 mass extinctions.
The cause of why the dinosaurs went extinct has been the subject of great debate, but there is now a consensus that a large meteorite struck earth and produced a dust cloud that circled the planet and blocked incoming solar radiation. This resulted in a complete halt to photosynthesis, and thus there was a total lack of food at the bottom of the food chain.
The sixth mass extinction is currently happening. Its different form the other ones because this mass extinction has human causes. These causes include habitat destruction, overharvesting, introduction to invasive species, and emerging species. Some scientists contest that species may not be able to move or adapt in time to avoid extinction. Recovery takes a ridiculously long time, so we need to find ways to reduce the cost of our actions on extinction rates.
- Friedland, Andrew, and Rick Relyea. "Chapter 2." Environmental Science for AP. 2nd ed. W.H. Freeman, 2015. 147-173. Print.