Biology: Chapter 16 Darwin's Theory of Evolution
Terms in this set (57)
change over time; the process by which modern organisms have descended from ancient organisms
preserved remains or traces of ancient organisms
selective breeding of plants and animals to promote the occurrence of desirable traits in offspring
heritable characteristic that increases an organism's ability to survive and reproduce in an environment
how well an organism can survive and reproduce in it's environment
process by which organisms that are most suited to their environment survive and reproduce most successfully
study of past and present distribution of organisms
structures that are similar in different species of common ancestry
body parts that share a common function, but not structure
structure that is inherited from ancestors but has lost much or all of its original function
the patterns of distribution of living organisms now and in the past (where do they live, where have they lived)
Types of Distribution
1) Cosmopolitan - live everywhere
ex. fruit flies
2) Endemic - restricted to a certain area
ex. Alabama Red Hills Salamander,
Alabama Red Turtle
3) Disjunct - separated
(they may be separated geographically)
ex. Galapagos Tortoise
How do we use biogeography?
1) we look at how closely related species are different
ex. apple maggot fly
- once infested Hawthornes in Australia
2) we look at how distantly related species are similar
ex. Dingo (canine) and Thylacine (marsupial)
- similar body shape, but the Thylacine is more closely related to the Kangaroo
- they live in the same habitat, but have different adaptations
What was Charles Darwin's contribution to science?
Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors
What three patterns of biodiversity did Darwin note?
1) species vary globally
2)species vary locally
3)species vary over time
Species Vary Globally
Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe.
Species Vary Locally
Darwin noticed that different, yet related, animal species often occupied different habitats within a local area.
Species Vary Over Time
Darwin noticed that some fossils of extinct animals were similar to living species.
What is evolution?
the process of change over time
Darwin found fossils of many organisms that did not resemble any living species. How might this finding have affected his understanding of life's diversity?
The finding might have helped him understand that many species go extinct, while others evolve into different species. Darwin might have inferred that Earth's current diversity is less than the total diversity of living things that have ever existed.
Example of Local Variation
An example of local variation comes from the Galapagos Islands. These islands are close to one another, yet they have different ecological conditions. Several islands were home to distinct forms of giant land tortoises.
Among tortoises in the Galapagos Islands, shell shape corresponds to different habitats. Isabela Island has high peaks, is rainy, and has abundant vegetation. Hood Island, in contrast, is flat, dry, and has sparse vegetation.
The Isabela Island Tortoise have dome-shaped shells and short necks. Vegetation on this island is abundant and close to the ground. The Hood Island Toroise has curved shells that are open around their long necks and legs. This enables them to reach the island's sparse, high vegetation.
What did Hutton and Lyell conclude about Earth's history?
Hutton and Lyell concluded that Earth is extremely old and that the processes that changed Earth in the past are the same processes that operate in the present.
What were a few of Hutton's hypotheses?
Hutton recognized the connections between a number of geological processes and geological features, like mountains, valleys, and layers of rock that seemed to be bent or folded. For example, he realized that certain kinds of rock are formed from molten lava.
He also proposed that forces beneath Earth's surface can push rock layers upward, tilting or twisting them in the process. Over long periods, those forces can build mountain ranges.
What was Hutton's conclusion?
Hutton concluded that our planet must be much older than a few thousand years. He introduced a concept called deep time to explain this reasoning.
What is deep time?
The idea that our planet's history stretches back over a period of time so long that it is difficult for the human mind to imagine.
What were a few of Lyell's hypotheses?
Lyell argued that laws of nature are constant over tine and that scientists must explain past events in terms of processes they can observe in the present. Like Hutton, Lyell argued that Earth was much older than just a few thousand years.
How did Lamarck propose that species evolve?
Lamarck suggested that organisms could change during their lifetime by selectively using or not using various parts of their bodies. He also suggested that individuals could pass these acquired traits on to their offspring, enabling species to change over time.
What was Malthus's view of population growth?
Malthus reasoned that if the human population grew unchecked, there wouldn't be enough living space and food for everyone.
How is inherited variation used in artificial selection?
In artificial selection, nature provides the variations, and humans select those they find useful.
What were Hutton's and Lyell's ideas about the age of Earth and the processes that shape the planet?
Hutton thought geological processes, such as mountain building, take a very long time, so Earth must be much older than most people believed. Lyell expanded on Hutton's idea by suggesting that the same geological processes that changed Earth in the past are still at work today.
What is an acquired characteristic? What role did Lamarck think acquired characteristics played in evolution?
An acquired characteristic is a trait altered during an organism's life. Lamarck thought acquired characteristics could be passed on to offspring.
What part of Lamarck's hypotheses have been proved wrong? What did Lamarck get right?
Lamarck's idea about the inheritance of acquired characteristics and an organism's tendency toward perfection have been proven wrong. However, he was right that species are not fixed but change in response to their environment.
According to Malthus, what factors limit human population growth?
living space and food
How did Malthus influence Darwin?
Malthus got Darwin thinking about overproduction of offspring. The idea that many more organisms are produced than can survive led Darwin to suggest a mechanism that explains which organisms survive to reproduce.
What is artificial selection?
the process of allowing only organisms with desirable traits to reproduce in order to increase the number of individuals with those traits
Could artificial selection occur without inherited variation?
No, there would be nothing to select if all the members of a species were identical.
Under what conditions does natural selection occur?
Natural selection occurs in any situation in which more individuals are born than can survive (the struggle for existence), there is natural heritable variation (variation and adaptation), and there is variable fitness among individuals (survival of the fittest).
What does Darwin's mechanism for evolution suggest about living and extinct species?
According to the principle of common descent, all species-living and extinct- are descended from ancient common ancestors.
What happens in the process of natural selection?
Natural selection is the process by which organisms with variations most suited to their environment (adaptations) survive and reproduce more often than individuals without the adaptations.
Why do organisms with greater fitness generally leave more offspring than organism's that are less fit?
Individuals with high fitness have adaptations that make them better suited for their environment, so they survive and reproduce more often than individuals who are less fit.
Why were Hutton's and Lyell's ideas important to Darwin?
Hutton and Lyell thought Earth was very old. This was important to Darwin, because it allowed enough time for natural selection to work.
How are natural selection and artificial selection similar? How are they different?
In both artificial and natural selection, certain individuals in a population disproportionately pass on their traits to the next generation, resulting in changes to the population. However, in natural selection the environment-not a farmer or animal breeder-determines which individuals pass on their traits.
How does the geographic distribution of species today relate to their evolutionary history?
Patterns in the distribution of living and fossil species tell us how modern organisms evolved from their ancestors.
How do fossils help to document the descent of modern species from ancient ancestors?
Many recently discovered fossils form series that trace the evolution of modern species from extinct ancestors.
What do homologous structures and similarities in embryonic development suggest about the process of evolutionary change?
Evolutionary theory explains the existence of homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. Similar patterns of embryological development provide further evidence that organisms have descended from a common ancestor.
Do you think the shell of a clam and the shell of a lobster are homologous or analogous structures?
The shell of a clam and the shell of a lobster are probably analogous, because they have a common function (protection, support), but not a common structure.
How can molecular biology be used to trace the progress of evolution?
At the molecular level, the universal genetic code and homologous molecules provide evidence of common descent.
What does recent research on the Galapagos finches show about natural selection?
The Grants have documented that natural selection takes place in wild finch populations frequently, and sometimes rapidly. The Grants' work shows that variation within a species increases the likelihood of the species' adapting to and surviving environmental change.
What is biogeography?
the study of where organisms live now and where they and their ancestors lived in the past
Why do distantly related species in very different places sometimes share similar traits?
because they evolved similar adaptations to the same environmental conditions in different places
Why are fossils important evidence for evolution?
Fossils provide direct evidence of extinct organisms and allow scientists to trace the evolution of modern species from extinct ancestors.
Explain the difference between homologous and analogous structures. Which are more important to evolutionary biologists? Why?
Homologous structures share a common ancestry, but not necessarily a common function. Analogous structures share a common function, but do not share a common ancestry. Generally, homologous structures are more important to evolutionary biologists, because they provide evidence of evolutionary relationships.
How do vestigial structures provide evidence for evolution?
Vestigial structures offer clues about the ancestors of organisms, because they are the remnants of structures with once important functions.
What is the relationship between Hox genes and embryological development?
Hox genes control the timing of development and growth in embryos.
Organisms A and B have very similar Hox genes, and their embryos, in the earliest stages of development, are also very similar. What do these similarities indicate about the ancestry of organisms A and B?
The similarities indicate that organisms A and B likely share a recent common ancestor.
What hypothesis have the Grants been testing?
Natural selection shaped the beaks of different bird populations.
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