Evolution and Natural Selection Flashcards
Historical Figures: Hutton
introduced ideas of gradualism
Historical Figures: Cuvier
Discusses fossils and extinction
Historical Figures: Lyell
gradualism and uniformic change over time
Historical Figures: Linnaeus
Classification scheme: binomial nomenclature
Historical Figures: Lamark
Gave a mechanism for species change over time: a change in an animal during its lifetime can be passed down to its offspring
Historical Figures: Malthus
Was an economist trying to answer: Why do people suffer?
Historical Figures: Malthus’ view
suffering occurs because populations have the potential of exponential reproduction which leads to resource expenditure.
Historical Figures: Darwin and _____
Wallace
3 Things that Wallace and Darwin noticed: 1
1) For any given current species, there are many different other species and fossils of past species that resemble that current species.
3 Things that Wallace and Darwin noticed: 2
2) There are Geographical Gradients of change in species. E.g: Island species resemble their mainland counterparts, but are slightly different.
3 Things that Wallace and Darwin noticed: 3
3) Organisms have traits to match their environment.
Adaptations:
Inherited characteristics of organisms that enhance their survival and reproduction in specific environments.
Darwin’s 2 Key Points. (1)
There exists descent with modification: Species today are ancestral species that have changed in time.
Darwin’s 2 Key points. (2)
Changes in time occur by the mechanism of Natural Selection.
4 Observations of Natural Selection (1)
1) Individuals in a population vary in their traits.
4 Observations of Natural Selection (2)
2) The individual traits in a population are heritable.
4 Observations of Natural Selection (3)
3) Organisms are capable of producing more offspring than the environment can support (malthus)
4 Observations of Natural Selection (4)
4) Many offspring do not survive.
2 Inferences of Natural Selection: (1)
1)Individuals that are well suited to their environments tend to leave more offspring than other individuals.
2 Inferences of Natural Selection: (2)
2) Over time, favorable traits will accumulate in a population.
5 Evidences for Natural Selection and Descent with Modification: Artificial Selection
We can control some selections and see the results.
5 Evidences for Natural Selection and Descent with Modification: Direct observations of evolutionary change
Self explanatory
5 Evidences for Natural Selection and Descent with Modification: Fossil Record
Self explanatory
5 Evidences for Natural Selection and Descent with Modification: Homology
Finding similar physiological traits in animals that do not seem similar
5 Evidences for Natural Selection and Descent with Modification: Biogeography
Geographic distribution of species
Give three types of Homology
Vestigial Structures: old remnant structures with no apparent use, Embryological homology, and molecular homology.
Endemic Species
Species that are only found in one location
Definition of Microevolution
Change in allele frequency from one generation to the next.
Definition of Population
Localized group of individuals capable of interbreeding and producing fertile offspring
Give 2 reasons why variation is important:
Variation is the raw material for evolution, and an environment is unlikely to be constant
Gene Pool
All the alleles in a population
Polymorphism
There are 2 or more versions of a trait in a population.
What creates genetic variation? (2)
Mutation or chromosome level events, and sexual reproduction.
Basic list of what drives change in genetic variation: (4)
Mutation, Genetic Drift, Gene Flow, Natural Selection
Genetic Drift: Due to _____ change events, tends to _____ genetic variation in a population. Especially crucial in _____ populations.
Genetic Drift: Due to RANDOM change events, tends to DECREASE genetic variation in a population. Especially crucial in SMALL populations.
Genetic Drift: Can be achieved via the ____ effect, and the ____ effect.
Genetic Drift: Can be achieved via the FOUNDER effect and the BOTTLENECK effect.
Genetic Drift: Founder Effect
Formation of a new population which could be changing allele frequency.
Genetic Drift: Bottleneck Effect
If many die, then by chance, allele frequency of the surviving population could change.
Gene Flow
Change in allele frequency due to immigration/input of gametes from other populations.
Gene Flow tends to ___ genetic variation. WHY?
Gene flow tends to reduce genetic variation. This is because AMONG populations, the sharing of genes decreases differences.
Natural Selection is the only process that has consistently ___ effects.
Natural Selection is the only process that has consistently POSITIVE effects.
Directional Selection
Selection favors individuals at one end of the phenotypic ratio.
Disruptive/Diversifying Selection
Selection favors individuals on extreme ends on phenotypic ratio.
Stabilizing Selection
Selection favors the intermediate phenotypes.
Why are we concerned about small populations?
Small populations can experience greater drift than natural selection.
In a small population, a ____ allele is just as likely to go to the next generation as a good allele, because
Natural selection is not fast enough to account for random drift.
In a small population, the decrease of fitness in a population has _____ feedback.
Positive
Overall, passing genes is (more/less) important than survival.
More
Intrasexual Selection
Competition (antlers)
Intersexual Selection
need to be attractive to opposite sex
Sexual Dimorphism
Differences in size, shape, and behavior between genders.
Animals must optimize their choice between _____ and _____.
Copulating, and foraging.
6 Reasons why Natural Selection does not produce perfectly adapted organisms: Natural selection works with _____ variation.
available
6 Reasons why Natural Selection does not produce perfectly adapted organisms: The world and the best adaptation can _____ in _____ and _____.
The world and the best adaptation can VARY in TIME and SPACE.
6 Reasons why Natural Selection does not produce perfectly adapted organisms: Natural Selection takes _____.
Time
6 Reasons why Natural Selection does not produce perfectly adapted organisms: Natural Selection can be outweighed by another _________ force.
Microevolutionary
6 Reasons why Natural Selection does not produce perfectly adapted organisms: There are often tradeoffs, for example, between ______ and ______.
Survival, and reproduction.
6 Reasons why Natural Selection does not produce perfectly adapted organisms: Not all variation is subject to Natural Selection. These traits are known as ____ ____.
Neutral variation.
Evolutionary Trap
The environment changes in a way which preset cues no longer match the ideal outcome.
Speciation
The evolution of a new species.
Macroevolution
Evolutionary change above the species level.
BSC (acronym, definition, flaw)
Biological Species Concept: A species is defined by being able to interbreed and produce fertile offspring. One flaw is asexual reproducers.
ESC (acronym, definition)
Ecological Species Concept: A species is defined by existing in the same ecological niche.
MSC (acronym, definition)
Morphological Species Concept: A species is defined by having similar size and shape.
Reproductive Isolation
The existence of biological barriers that prevent individuals from interbreeding
Give 4 examples of PreZygotic Barriers
Animals must be in the same 1) Place 2) Time 3) Behavior 4) Mechanical fit 5) Fertilization details
Give 2 major PostZygotic Barriers
1) Development must proceed smoothly 2) Future fertility of hybrids.
Allopatric Speciation
New species created via geographic separation/divergence.
Regions with (More/less) geographic barriers tend to create more species
Regions with MORE geographic barriers tend to create more species
Endemic Species
Species that only exists in one place
Sympatric Speciation
Speciation emerging without geographic separation.
Sympatric Speciation Mechanism 1:
Polyploidy–“many chromosomes
Sympatric Speciation is very common in _____
plants
During Sympatric Speciation _____ _____ is required
During sympatric speciation, reproductive isolation is required.
Sympatric Speciation Mechanism 2,3:
Different mating preferences, habitat preferences.
2 models for speciation
Punctuated equilibrium, and gradualism
Adaptive Radiation
Sudden period of evolutionary change
Adaptive Radiation frequently occurs when…
species colonate a new environment
new key evolutionary change that allow movement to a vacant niche.
In the history of the earth, key events are often linked with ___ ____.
Key events are often linked with novel adaptations.
Mass extinctions can provide opportunities for ______ ____.
Mass extinctions can provide opportunities of surviving taxa