Ch.22 - Descent w Mods Flashcards
Summarize contributions of Aristotle, Linnaeus, and Cuvier
Aristotle - species never changed; arranged in order of increasing complexity (scala naturae)
Linnaeus - nested hierarchical system (still used); helped classify diversity.
Cuvier - “Father of paleontology”; observed change across different strata (layers) in fossil record; oldest layers were most diff fr living orgs.
Summarize contributions of Hutton and Lyell
Hutton - same gradual geologic processes were resp for dramatic features of Earth
- E.g. valley slowly filling w water becomes a river
Lyell - built on Hutton’s idea to dev uniformitarianism; argued that Earth was much older than few thousand years
Some scientists had thought that species do change over time, but _________ was the first to suggest a mechanism for how this happened.
Some scientists had thought that species do change over time, but Lamarck was the first to suggest a mechanism for how this happened.
- Use and disuse
- Inheritance of acquired characteristics
- NOT supported by evidence
____________ was the idea that mechanisms of geologic change were constant over time
Uniformitarianism was (Lyell’s) idea that mechanisms of geologic change were constant over time
Darwin observed that a finches’ beak matched its ________
Darwin observed that a finches’ beak matched its food source
After receiving a manuscript from Alfred Russell Wallace on his hypothesis of natural selection, Drawin eventually published “The Origin of Species” (1859). Why was Darwin’s theory so well accepted by the bio community?
Immaculate logic; avalanche of supporting evidence
What are the two main ideas in “The Origin of Species”?
Descent with modification
- Pattern of evol change is revealed by data fr a range of scientific disciplines
- Data are facts
Natural selection
- Process of evol consists of mechanisms that produced observed patterns of change.
Describe the idea of descent with modification wrt ancestry, adaptation, and diversity.
All orgs descended from a distant common ancestor
Descendents accumulated modifications → survive in diff environs
Over long time periods, descent w mod led to great diversity of life we see today
Darwin noted that humans have modified other species by selecting and breeding individuals with desired traits, a process called __________
Darwin noted that humans have modified other species by selecting and breeding individuals with desired traits, a process called artificial selection
Two observations of natural selection:
- Members of a ________ often vary in ________ traits.
- All species can produce _____ (more/less) offspring than the environ can support, and many of these offspring ______________.
Two observations of natural selection:
- Members of a population often vary in inherited traits.
- All species can produce more offspring than the environ can support, and many of these offspring fail to survive/reprod.
What are the two key observations of natural selection?
Two observations of natural selection:
- Members of a population often vary in inherited traits.
- All species can produce more offspring than the environ can support, and many of these offspring fail to survive/reprod.
What are the two key inferences of natural selection?
Two inferences of natural selection:
- Individuals whose inherited traits give them a higher probability to survive/reprod in a given environ tend to leave more offspring than other individuals.
- Unequal ability of individuals to survive/reprod will lead to accumulation of favorable traits in the population over generations.
I.e. Traits that are advantageous and heritable will accumulate in the population. Over time → match b/w orgs and environ.
Lamarck proposed ideas of use/disuse and inheritance of acquired characteristics. Describe these ideas and where they went wrong.
Where Lamarck got it wrong:
Use and disuse: parts of the body that are used extensively become larger and stronger, while rarely used parts deteriorate
Inheritance of acquired characteristics: Adults can pass on the traits that they have developed to their offspring
These mechanisms are NOT supported by evidence
A(n) __________ is an inherited characteristic of an individual that enhances its survival and reproduction in a specific environment.
An adaptation is an inherited characteristic of an individual that enhances its survival/reprod in a specific environment.
T/F: Some individuals can evolve in their lifetime.
FALSE
Individuals do NOT evolve in their lifetimes. Populations evolve over time.
- Acclimation: short-term physio changes in an individual in response to the environ.
Describe how homology helps support DWM/NS.
Homology: similarity resulting from common ancestry
- Similar trait in two orgs due to descent fr common ancestor.
- Orgs live in diff environs → trait may now serve diff functions
Homologous structures - anatomical resemblances that represent variations on a structural theme present in a common ancestor.
Describe how the fossil record supports DWM/NS.
Fossils can document imp transitions:
- Animal and plant forms change over time
- Time-span is immense
- Extinction is the norm (99.9%)
- Earth is changing faster than species can keep up
