Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
Speciation |
Origin of new species |
|
|
Microevolutoin |
Changes in allele frequency in population over time |
|
|
Macroevolution |
- Progressive evolution of a new capability - Usually crosses several speciation events; but some speciation is just one mutation - Broad patterns of evolutionary change above the species level |
|
|
Biological Species Concept |
- Emphasizes reproductive isolation - Cannot evaluate fossils or extinct species, or organisms that reproduce asexually - Designated by the absence of gene flow - Emphasizes separateness of species from one another due to reproductive barriers |
|
|
Biological Species Concept |
- States that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; do not breed successfully with other populations - Gene flow between populations holds the phenotype of a population together |
|
|
Reproductive Isolation |
- Existence of biological factors (barriers) that impede two species from producing viable, fertile offspring - Distinguish between geographic barriers which may not be permanent - True _____ is permanent - May arise as a result of genetic divergence |
|
|
Gene pools / Alleles |
Two populations of the same species can share __________, different species cannot. Evolution will proceed separately. |
|
|
Habitat Temporal Behavioral Mechanical Gametic |
5 Types of Prezygotic Barriers of Reproductive Isolation |
|
|
Reduced Hybrid Viability Reduced Hybrid Fertility Hybrid Breakdown |
3 Types of Postzygotic Barriers of Reproductive Isolation |
|
|
Prezygotic Barriers |
Block fertilization from occurring by: - Impeding different species from attempting to mate (unattractive, bad timing, wrong location) - Preventing the successful completion of mating (pieces don't fit) - Blocking sperm/egg fusion |
|
|
Habitat Isolation |
- 2 Species encounter each other rarely, or not at all, because occupy different _____, though not isolated by physical barriers |
|
|
Temporal Isolation |
- Species breed at different times of the day, or different seasons, or different years - Cannot mix gametes |
|
|
Behavior isolation |
- Courtship rituals and other behaviors unique to a species are effective barriers |
|
|
Mechanical Isolation |
- Morphological differences can prevent successful mating Ex: Different areas of genitals |
|
|
Gametic Isolation |
- Sperm of one species may not be able to fertilize eggs of another species Ex: Sea urchin and sponges release gametes into water, but only received by those compatible |
|
|
Postzygotic Barriers |
- Prevent the hybrid zygote from developing into viable, fertile adult - From missing genes (reduced hybrid viability or fertility) - From mismatched chromosomes, lost during meiosis (hybrid breakdown) |
|
|
Reduced hybrid viability |
- Genes of the different parent species may interat and impair the hybrid's developmenet |
|
|
Reduced hybrid fertility |
- Even if hybrids are vigorous, they may be sterile Ex: mule |
|
|
Hybrid Breakdown |
- Some first generation hybrids are fertile, but when mating with another species or with either parent species, offspring are feeble or sterile Ex: Plants |
|
|
Morphogical Species Concept |
- Defines a species by structural features - Applies to sexual and asexual species, but relies on subjective criteria |
|
|
Ecological Species Concept |
- View a species in terms of its ecological niche - Applies to sexual and asexual species and emphasizes the role of disruptive selection |
|
|
Phylogenetic Species Concept |
- Defines a species as the smallest group of individuals on a phylogenetic tree - Applies to sexual and asexual species, but it can be difficult to determine the degree of difference required for separate species |
|
|
Allopatric Speciation |
- Population forms new species while geographically isolated from parent population |
|
|
Sympatric Speciation |
- Subset population forms a new species without geographic separation - Can be driven by sexual selection/selective mutation/disruptive selection - Also from polyploidy |
|
|
Polyploidy |
- Arise from accidents in cell division - Results in extra sets of chromosomes - Common in plants |
|
|
Autopolyploid |
- Individual with more than two chromosome sets, derived from one species |
|
|
Allopolyploid |
- Species with multiple sets of chromosomes derived from different species |
|
|
Hybrid Zones |
- Region in which members of different species mate and produce hybrids - Result of mating between species with incomplete reproductive barriers |
|
|
Geographic Isolation |
- Cause of speciation - Doesn't PROVE speciation - Leads to biological barriers, reproductive isolation |
|
|
1. Inbreeding 2. Outbreeding |
Generally, ___1___ is not good, causes a "genetic drift" -like condition within families. ___2___ is better, resulting in healthier, smarter, taller offspring because of more heterozygous loci. |
|
|
Genetic Mistakes |
________ can make you only self-fertile |
|
|
Reinforcement Fusion Stability |
3 Possible Outcomes of Species meeting in a hybrid zone |
|
|
Fusion |
- Weakens reproductive barriers, when hybrids are fit as parents, and substantial gene flow occurs between species |
|
|
Stability |
- Continued formation of hybrid individuals - Extensive gene flow from outside the hybrid zone can overwhelm selection for increased reproductive isolation inside the hybrid zone |
|
|
Macroevolution |
- Cumulative effect of many speciation and extinction events |
|
|
Reinforcement |
- Strengthening Reproductive Barriers cause gradual cessation of hybrids, when they are generally less fit than members of their parent species |
