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1.1 The study of life Read Online
Viewed from space, Earth offers no clues about the diversity of life forms that reside there. The first forms of life on Earth are thought to have been microorganisms that existed for billions of years in the ocean before plants and animals appeared. The mammals, birds, and flowers so familiar to us are all relatively recent, originating 130 to 200 million years ago. Humans have inhabited this planet for only the last 2.5 million years, and only in the last 200,000 years have humans started looking like we do today.
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Start Quiz | Download PDF | |
Start Quiz | Download PDF | |
Start Quiz | Download PDF | |
Start Quiz | Download PDF | |
Start Quiz | Download PDF |
In BIO101, you were introduced to biology on a microscopic scale when you learned about the functions of molecules, genes, and cells. In this course, you will learn about biological changes that happen on a very large scale, across entire populations of organisms and over the course of millions of years, in the form of evolution and ecology. Evolution, the process by which different species of organisms have developed and diversified from their evolutionary forbears, has been a central theme in the field of biology ever since Darwin first published his theories about it. Mounting evidence from many different branches of science all point to the fact that species have experienced a gradual but definite physical change. In this course, we will learn about evolution and theories that stem from evolution.
Question: Determine if the examples below (I through III) are due to the effects of the environment on phenotypic plasticity or evolutionary change. I. An individual Common Ice Plant has the ability to change from C3 photosynthesis to CAM photosynthesis when it becomes stressed by low water or high salinity. II. When plants become too dense and competition is high, some Aphid species grow wings between generations to enable dispersion, and then the next generation is without wings. III. Bats are able to fly with wings that are paws with really long fingers and skin stretched between them; one way this could happen is if these finger bones grew at a faster rate than the rest of the body.
Choices:
I = plastic phenotype, II = phenotypic plasticity, III = evolutionary change
I = plastic phenotype, II = evolutionary change, III = evolutionary change
I = evolutionary change, II = evolutionary change, III = plastic phenotype
I = evolutionary change, II = plastic phenotype, III = plastic phenotype
Question: Fill in the blanks. One of the most distinguishing characteristics separating Darwin's theory of natural selection from other theories, particularly Lamarck's, is the idea that ___________ evolve, while _____________ do not.
Choices:
species, populations
populations, individuals
individuals, populations
individuals, species
Question: A local snail has 3 phenotypes with the heterozygous individuals showing incomplete dominance. Therefore, individuals with a genotype of BB are brown, Bb are tan, and bb are white. These snails are particularly tasty to the local birds. Due to a recent storm, the species has migrated to a different beach in which the current environment only affords camouflage for the brown individuals. Therefore, the tan and white individuals are seen and eaten more easily by the birds. Which graph below describes this example of selective pressure?
Choices:
A - Directional
A - Stabilizing
B - Disruptive
C - Directional
Question: A local snail has 3 phenotypes with the heterozygous individuals showing incomplete dominance. Therefore, individuals with a genotype of BB are brown, Bb are tan, and bb are white. These snails are particularly tasty to the local birds. Due to a recent storm, their current environment only affords camouflage for the tan individuals, because all the brown and white tide pools have been covered by tan sand by the storm. Therefore, the brown and white individuals are seen and eaten more easily by the birds. Which graph below describes this example of selective pressure?
Choices:
B - Directional
B - Stabilizing
C - Disruptive
A - Negative
Question: Evolutionary synthesis brought together many ideas and data from several areas of biology, particularly ecology, genetics, botany, cytology, systematics, morphology, and paleontology. Dobzhansky & Mayr were most involved in which field?
Choices:
Genetics
Systematics
Morphology
Paleontology
Question: Male elk with large groups of mating females, or harems, tend to have individually specific phenotypic traits including large antlers and body size. If a male with a smaller body size is seen with a large group of females, then which advantage is most likely in effect for these females to choose this male?
Choices:
Direct benefits
"Sexy Sons"
Good Genes Hypothesis
Red Queen Hypothesis
Question: Fill in the blanks. Ornate peacock feathers are thought to be a trait that was developed with the function to maximize reproductive success, not necessarily to help the individuals survive. This is an example of __________ selection and is solely based on an individual's _______________.
Choices:
natural, phenotype
sexual, phenotype
natural, genotype
sexual, genotype
Question: A local snail has 3 phenotypes with the heterozygous individuals showing incomplete dominance. Therefore, individuals with a genotype of BB are brown, Bb are tan, and bb are white. These snails are particularly tasty to the local birds. Their current environment only affords camouflage for the brown and white individuals on brown and white rock tide pools. Therefore, the tan individuals are seen and eaten more easily by the birds. Which graph below describes this example of selective pressure?
Choices:
A - Disruptive
C - Stabilizing
B - Disruptive
A - Directional
Question: Female northern cardinals choose males with the brightest red feathers. It has been shown that these males more frequently feed their young, which allows the mother to be able to raise more offspring. This advantage for sexual selection is best explained by which of the following?
Choices:
Direct benefits
"Sexy Sons"
Good Genes Hypothesis
More than one of the above
Question: Male specimen "A" is 54 years old, has 14% body fat, exercises daily, eats well, and has 2 children. Male specimen "B" is 50 years old, has 29% body fat, exercises occasionally, eats a typical American diet, and has 3 children. Male specimen "C" had 32% body fat, exercised rarely, did not eat well, and has 5 children. "C" died at age 47. In terms of biological fitness, at this time, which individual is the most fit?
Choices:
Individual "A" because he is the healthiest
Individual "B" because he is the youngest that is still alive
Individual "C" because he had the most children
Individuals "A" & "B" because they lived longer than "C"
Question: Due to a recent hurricane, the local seeds available for forage are much smaller than in the past. Local seed eating birds that were adapted to harvest the larger seeds appear to be having a hard time obtaining the smaller seeds. However, those individuals with smaller beaks are finding it easier to get the seeds, and with less competition. According to the theory of natural selection, what changes will likely occur in this population?
Choices:
Over time, individuals will show smaller beaks, because this is more advantageous for the birds.
The birds with the smaller beaks will most likely be more successful in foraging and therefore breeding, which over time will lead to a population with smaller beak size.
The birds will choose to pass on the smaller beak size gene to their offspring, because it is now the better phylogeny.
The next generation of birds will have smaller beaks, because they will be able to forage better.