Biology 1115 Chapter 22
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Darwin noted that current species are ______________.
descendants of ancestral species
Descent with modification
How did Aristotle view species?
he viewed species as fixed
How did Carolus Linnaeus interpret organismal adaptations?
he interpreted them as evidence that the Creator has designed each species for a specific purpose
What did jean-baptiste Lamarck hypothesize about species evolving?
that species evolve through the use and disuse of body parts and the inheritance of acquired characteristics
What did Lyell's principle of uniformitarianism state?
- states that the mechanisms of change are constant over time
- this greatly influenced Darwin's thinking
What was Darwin influenced by?
Lyell's Principle's of Geology
In reassessing his observations, Darwin perceived ______________ and ____________ as closely related processes.
- adaptation to the environment
- origin of new species
What are the 2 main ideas Darwin developed?
- Descent with modification: explains life's unity and diversity (pattern)
- Natural Selection: cause of adaptive evolution (process)
What does the phrase "descent with modification" mean?
refers to the view that all organisms are related through descent from an ancestor that lived in the remote past
What is artificial selection?
modifying species by selecting and breeding individuals with desired traits
Darwin described four observations of nature and from the drew 2 inferences. What are the observations?
- 1. members of a population often vary greatly in their traits
- 2. traits are inherited from parents to offspring
- 3. all species are capable of producing more offspring than the environment can support
- 4. b/c of lack of food & other resources, many offspring don't survive
Darwin described four observations of nature and from the drew 2 inferences. What are the 2 inferences?
- 1. 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
- 2.This unequal ability of individuals to survive and reproduce will lead to the accumulation of favourable traits in the population over generations
What process explains the match between organisms and the environment?
If some heritable traits are advantageous, these will accumulate in the population, and this will increase the frequency of individuals with adaptations.
What does natural selection increase?
Natural selection increases the adaptation of organisms to their environment over time
If an environment changes over time, how will natural selection effect it?
natural selection may result in adaptation to these new conditions and may give rise to new species
__________ do not evolve, __________ evolve over time.
Natural selection does not create new traits, but edits or selects for traits ____________ in the population.
Adaptations vary with __________________.
What is an example of evidence for ongoing natural selection?
evolution of antibiotic resistant bacteria
A drug does not _______ drug resistant pathogens
The use of antibiotics to kill bacteria _________ for bacteria resistant to these drugs.
is similarity resulting from common ancestry
Define homologous structures.
- common ancestors
- same basic structures
- sometime different use
What are vestigial structures?
- are remnants of features that served important functions in the organism's ancestors.
- structures we don't use anymore
what is an example of homologies at the molecular level?
genes shared among organisms inherited from a common ancestor.
What are evolutionary trees?
are hypotheses about the relationships among different groups
convergent evolution produces?
define convergent evolution.
evolution of analogous structures in distantly related groups
What are analogous structures?
- different ancestors
- different basic structures
- same function
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