Chapter 4.2 Flashcards
What is a scientific hypothesis?
A statement that provides a possible answer to a question
How are hypotheses tested?
Experiments, observation, and developing models of data
What is a scientific theory?
When hypotheses consistently lead to successful predictions and explanations are synthesized into a general statement that explains and makes predictions
What is the theory of evolution by natural selection?
A well supported, widely accepted, explanation of how life has changed and continues to change during earth’s history
What did Plato and Aristotle believe?
- That all life existed in a perfected and unchanging form.
- All species of organisms had been created independently of one another and had remained unchanged ever since.
Who was the first person to challenger Aristotle and Plato?
French naturalist Georges-Louis Leclerc
What did Georges-Louis Leclerc publish and what was it about?
A 44-volume Histoire Naturelle, which compiled his understandings of the natural world
What did Georges-Louis Leclerc speculate?
That apes and humans were similar so, they must have a common ancestor and that earth was much older than 6000 years old
Who developed the science of paleontology?
Georges Cuvier
What is paleontology?
The study of ancient life through the examination of fossils
What did Cuvier find in his paleontology?
- Each stratum (layer of rock) is characterized by a unique group of fossil species.
- The deeper (older) the stratum, the more different the species are from modern life
What is a stratum?
A layer of rock
What evidence shows that species can become extinct?
As you go from stratum to stratum you can see that species appeared and disappeared overtime
What did Cuvier propose to explain his observations of species appearing and disappearing?
Cuvier proposed the idea that Earth experienced many destructive natural events, such as floods and volcanic eruptions, in the past. These were called revolutions
What are revolutions?
Destructive natural events in the past that were violent enough to kill many species
What did Charles Lyell believe in terms of destruction of species?
That geological processes operated at the same rates in the past as they do today
What did Lyell theorize in terms of the earth’s changing?
- He proposed that geological processes operated at the same rates in the past as they do today.
- If geological changes are slow and continuous rather than catastrophic, then Earth might be more than 6000 years old.
- Lyell theorized that slow, subtle processes could happen over a long period of time and could result in substantial changes
What inspired Charles Darwin?
Lyell’s hypothesis that slow changes can be substantial over long periods of time and that it could also work with populations
What is a line of descent?
A progression, in which a series of fossils (from older to more recent) led to a modern species
How was a line of descent created?
By comparing current species of animals with fossil forms
What did Lamarck believe?
He thought that species increased in complexity over time, until they achieved a level of perfection
What did Lamarck believe about the characteristic that could be passed down to offspring?
He thought that characteristics, such as large muscles, that were acquired during an organism’s lifetime could be passed on to its offspring. Ex. a large, powerful chest muscles of a horse would be passed on to its offspring, which would have the same characteristics
What does inheritance of acquired characteristics mean?
The theory that characteristics acquired during an organism’s lifetime could be passed to its offspring
Who else reach conclusions that were similar to Darwin’s?
Alfred Russel Wallace
What did Darwin and Wallace agree on?
That populations changed as time passed, but they were unclear on how
What did Malthus propose about populations?
He said that populations produce more offsrpring than their environments could support and were eventually reduced by starvation
What organisms are more likely to survive in an environment?
Ones with physical, behavioral, and other traits that helped them to survive
What would competition for resources within a species do?
Competition would select for those with favorable traits that increased their ability to survive and reproduce. This ensures that future populations also had these traits
What 2 main ideas did Darwin propose in the “On the Origin of Species” essay?
- Present forms of life have arisen by descent and modification from ancestral species
- The mechanism for modification is natural selection working for long periods of time
