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.
Differentiate adaptation and acclimation
An adaptation is an inherited characteristic of an individual that enhances its survival/reprod in a specific environ.
An acclimation is a short-term physio change in an individual in response to the environ.
I.e. adaptations are inherited, whereas acclimations are direct environ responses.
T/F: Natural selection can create new traits or mutations.
FALSE
Natural selection can only ↑/↓ heritable traits that vary in a population. It does NOT create new traits/mutations.
There are other processes by wh a population can change. What differentiates natural selection from these processes?
Other processes do NOT lead to adaptive evolution.
Recall: an adaptation is an inherited characteristic of an individual that enhances its survival and reproduction in a specific environment.
What are the four types of data that document the pattern of evolution?
There are four types of data that document the pattern of evolution:
- Direct observations
- Homology - similarity resulting fr common ancestry
- Fossil record
- Biogeography
Describe two key examples of direct observation data supporting DWM/NS.
Soapberry bugs & Drug-resistance bac
Key pts:
- NS is a process of editing, not creating, i.e. selects for certain individuals.
- short reprod period → fast evol
- NS deps on time and place, i.e. adaptations are specific.
Soapberry bugs - a change in size of soapberry bug’s food source can result in evolution by NS for a corresponding change in beak size.
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.
Differentiate homologous strucs, vestigial strucs, and molecular homologies.
Homologous structures - anatomical resemblances that rep variations on a structural theme present in a common ancestor.
Vestigial structures - remains of features that were used in ancestors, but no longer functional.
Molecular homologies - genes shared among orgs inherited fr common ancestor
______________ is independent evolution of similar features in lineages that are not closely related.
Convergent evolution is independent evolution of similar features in lineages that are not closely related.
- Such features are analogous structures.
- I.e. OPPOSITE of homo strucs.
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
Describe how the biogeography supports DWM/NS.
Biogeography refers to the geo distrib of species
- Islands have many endemic species,
- often closely related to species on nearest mainland or island
- Pangea - 250 myo, single contitent
- Continental Drift - 200 myo
If all variation b/w individuals were due only to environ factors, why would natural selection in a population be completely prevented?
Natural selection has to do with hereditary traits
What is a population?
A localized group of organisms that belong to the same species.
Summarize Darwin’s two observations and two inferences.
Observations:
- Members of a population often vary in their inherited traits
- All species can reprod more offspring than environ can support → many will fail to survive/reprod.
Inferences:
- If inherited traits ↑ fitness in a given environ → tend to prod more offspring.
- Unequal fitness → accumulation of favorable traits in population over time.
How are phenotype, genotype, and evolution related?
Evolution - change in allele or genotype frequency over time
Genotype - individual’s genetic makeup (made of two alleles)
Phenotype - product of genotype and environ (Physical and molecular phenotype)
