Bio Chapter 22 Q's
In what ways were Lamarck's proposals regarding evolution similar to Darwin's? How did they differ?
similarities: adaptations lead to an increase in survival rates differences: Lamarck believed in the inheritance of acquired characteristics and use and disuse (he literally thought that giraffes could make their necks grow longer so they could reach food)
Describe the inferences Darwin made from his observations that led him to propose natural selection as a mechanism for evolutionary change
+Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals +This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations
Explain what evidence convinced Darwin that species change over time
+Members of a population often vary in their inherited traits +All species can produce more offspring than their environment can support and many of these offspring fail to survive and reproduce +Traits are inherited from parents to offspring +Overproduction leads to competition for food or toher resources
How did the geological views of Cuvier, Hutton, and Lyell differ? Which view did Darwin eventually agree with?
1) Cuvier: fossils are a record of change over time caused by CATASTROPHIC EVENTS 2) Hutton: slow, continuous process --> geological features 3) Lyell: uniformitarianism (same geological processes at the same rate in thep sat as TODAY, the earth is OLD, Darwin agreed with him)
Explain why the population is the smallest unit that can evolve
Because although natural selection occurs through interactions between individual organisms and their environment, INDIVIDUALS do not evolve; rather, it is the population that evolves over time
Distinguish between "descent with modification" and "natural selection". Which is most closely equivalent to the term "evolution"? Why are both terms crucial to Darwin's theory?
1) natural selection selects for the qualities that will best increase survival chances. these genes are then passed on and the species becomes "more fit" 2) descent with modification suggests that children will inherit the genes of their parents, but that sometimes these genes will be different because of mutations and/or variations
What important issues related to evolution were not addressed or explained by Darwin's original Theory?
1) origin of life 2) how variation arises 3) how inheritance works 4) why variation still exists (they can answer this) 5) "sudden" changes in fossil record 6) source of totally "new" characters
What are the most common erroneous ideas about evolution?
1) species are always evolving into "better" beings 2) evolution creates new forms of life because of dramatic mutations 3) an organism can evolve during its lifetime (NO) 4) an organism can influence the evolution of its own structures in response to its environment 5) evolution is a completely random process
Explain what an evolutionary tree is and how it is used
A diagram that reflects evolutionary relationships among groups of organisms Each branch point represents the common ancestor of the lineages beginning there and to the right of it A hatch mark represents a homologous characteristic shared by all the groups to the right of the mark
Briefly explain the predominate view of life's organization and history prior to the 1700s. Who was the greatest influence behind this view
Aristotle, Antiquity through the 1600s. -fixed ideal species -ladder of nature
Distinguish between artificial selection and natural selection
Artificial Selection: when humans modify other species over many generations by selecting and breeding individuals that possess desired traits Natural Selection: Process in which individual sthat have certain inherited traits tend to survive and reproduced at higher rates than other individuals because of those traits Artificial is forced, Natural is not
Using some contemporary examples, explain how natural selection results in evolutionary change
Changes in food source can result in evolution by natural selection Soapberry bugs feed most effectively when the length of their beak closely matches the depth of the seeds within the fruit; over time, the introduced goldenrain tree (rather than the native balloon vine) made the Soapberry bug grow shorter due to the seeds being closely to the surface Therefore, a change in the size of the soapberry bug's food source can result in evolution by natural selection for matching beak size
Distinguish between the scientific and colloquial use of the word "theory"
Colloquial use of the word "theory": is similar to the scientific hypothesis, which does not have a broad range of supporting evidence Scientific use of the word "theory": accounts for many observations and explains and integrates a great variety of phenomena
Explain convergent evolution using an example
Convergent evolution is the evolution of similar, or analogous, features in distantly related groups Analogous traits arise when groups independently adapt to similar environments in similar ways Ex) Marsupials are distinct from another group of animals called the eutherians; some marsupials have eutherian look alikes, like the sugar glider (Australia) and the flying squirrel (north america)
Describe Georges Cuvier's contribution to paleontology
Cuvier helped develop in large part, paleontolgy Cuvier examined strata near Paris and noted: The older the stratum, the more dissimilar its fossils were to current life-forms From one layer to the next, some new species appeared while others disappeared Inferred that extinctions must have been a common occurrence, but firmly opposed the idea of evolution
Explain how the principle of gradualism and Charles Lyell's theory of uniformitarianism influenced Darwin's ideas about evolution
Darwin agreed that if geologic change results from slow, continuous actions rather than from sudden events, then Earth must be much older than the widely accepted age of a few thousand years Also reasoned that perhaps similarly slow and subtle processes could produce substantial biological change
What is evolution
Darwin's proposal that Earth's many species are descendants of ancestral species that were different from the present-day species; can also be defined more narrowly by as a change in the genetic composition of a population fro generation to generation Can be viewed in two related but different ways: as a pattern and as a process
Explain how Cuvier and his followers used the concept of catastrophism to oppose the theory of evolution
Each boundary between strata represented a sudden catastrophic event, such as a flood, that had destroyed many of the species living in that area; such regions were later repopulated by different species immigrating from other areas
Who was Erasmus Darwin? How did he influence Charles Darwin?
He was Charles Darwin's grandfather. He published ideas about "natural philosophy" on evolution
Explain how homologies support Darwin's theory of evolution
Homologies are organismal features that are a similarity resulting from common ancestry, and the view of evolution as a remodeling process leads to the prediction that closely related species should share similar features, and they do
Describe how Lyell, Hutton, and Alfred Russell Wallace influenced Darwin
Hutton: idea of gradualism Lyell: idea of uniformitarianism; also pushed Darwin to publish his paper before someone else did Alfred Russel Wallace: developed a hypothesis of natural selection nearly identical to Darwin's and published his paper before Darwin had a chance to; Darwin soon published his book "On the Origin of Species by Means of Natural Selection" and Wallace admired enough by Darwin, thought Darwin should be known as the main architect of natural selection instead
Describe Jean Baptiste Lamarck's model for how adaptations evolve. Explain the challenges to Lamarck's ideas with respect to current understandings of biology
Lamarck explained his findings using two principles: +Use and disuse--the idea that parts of the body that are used extensively become larger and stronger, while those that are not used deteriorate +Inheritance of acquired characteristics--An organism could pass these modifications to its offspring Our understanding of genetics refutes his mechanism because experiments show that traits acquired by use during an individual's life are not inherited in the way proposed by Lamarck
Describe Carolus Linnaeus's contribution to Darwin's theory of evolution
Linnaeus developed the two-part format for naming species Linnaeus did not ascribe the resemblances among species to evolutionary kinship, but rather to the pattern of their creation Darwin argues that classification should be based on evolutionary relationships
Explain what Darwin meant by "descent with modification"
Organisms share many characteristics, leading Darwin to perceive the unity in life He attributed the unity of life to the descent of all organisms from an ancestor that lived in the remote past Also thought that as the descendants of that ancestral organism lived in various habitats, they gradually accumulated diverse modifications, or adaptations, that fit them to specific ways of life
Explain the problem with the statement that Darwinism is "just a theory"
The colloquial use of the word theory is different than the scientific theory. A scientific theory such as the theory of evolution by natural selection accounts for many observations and explains and integrates a great variety of phenomena; such a unifying theory does not become widely accepted unless its predictions stand up to thorough and continual testing by experiment and additional observation; just as the theory of evolution by natural selection demonstrates
Describe how Darwin used his observations from the voyage of the HMS Beagle to formulate and support his theory of evolution
The finches' various beaks and behaviors towards the specific foods available on their home islands, that he observed on the Galapagos Islands, helped Darwin realize that explaining such adaptations was essential to understanding evolution His explanation of how adaptations arise centered on natural selection
Explain how the fossil record supports evolution
The fossil record documents the pattern of evolution, sowing that past organisms differed from present-day organisms and that many species have become extinct Fossils also show the evolutionary changes that have occurred in various groups of organisms
Explain how an essay by Thomas Malthus influenced Charles Darwin
With his inferences, Darwin saw an important connection between natural selection and the capacity of organisms to overreproduce He made the connection when reading Malthus's paper contending that much of human suffering--disease, famine, and war--resulted from the human population's potential to increase faster than food supplies and other resources From this, Darwin realized the capacity to overreproduce was characteristic of all species; however, if some heritable traits are advantageous, these will accumulate in the population, and this will increase the frequency of individuals with those adaptations
On what basis did Linnaeus create his classification system?
from most inclusive to least (K to S)
Explain how the biogeography supports evolution
location of species throughout the world (corresponds to geographic history) -an explanation for distribution of species can be due to continental drift -Darwin noticed that life on the Galapagos islands was much more like South America (EX: iguanas)
How does natural selection lead to adaptation?...to increased species diversity?
natural selection selects the more favorable traits, which are passed on when offspring with those traits survive over the offspring with weaker traits. This then leads to those traits accumulating over time and becoming adaptations these adaptations then match species to environment and thus, new species are created