Diversity Of Life: 5 Word Scramble
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| Question | Answer |
| What are the two main species concept? | Morphological species concept and the biological species concept. |
| Morphological species concept | Simple judgement according to appearance/phenotypic traits. However, may be found invalid. |
| Biological species concept | A population that has potential to interbreed with one another in nature but are reproductively isolated from other populations. -Ernst Mayr (1963) |
| Reproductive Isolating Mechanisms (RIM) | Any heritable feature that prevents interbreeding between genetically different populations. |
| What are the 2 main categories of RIM? | Prezygotic and Postzygotic RIMs. |
| Prezygotic RIMs | It prevents zygote production through 5 isolation. Habitat/ecological isolation (reduced encounters), temporal isolation (mating periods), behavioral isolation (attraction), mechanical isolation (structural) and gametic isolation (incorrect chemicals). |
| Postzygotic RIMs | It prevents viable, fertile offspring. Reduced hybrid viability (zygote does not complete development and embryo aborts), reduced hybrid fertility (sterile offspring/no gene flow) and hybrid breakdown (hybrid offsprings die). |
| What are the 2 types of speciation? | Allopatric and sympatric speciation. |
| Allopatric speciation | The initial block of geneflow being a geographical barrier which results in physical separation between two populations into different areas. |
| Sympatric speciation | The reproductive isolation within the area of the parent population (different preference/trends). |
| What are the 2 ways geographical barriers may arise? | It may arise through development over time or through colonization in a new area. |
| Adaptive radiation | A process commonly found on island chains where the population occupies different islands and adapt to different conditions/lifestyles. |
| What are the possible mechanisms for sympatric speciation? | Ecological methods and sexual selection methods, and polypoidy (in plants). |
| Ecological methods in sympatric speciation | Tendency for individuals with a dependency on a particular lifestyle/food source to mate with similar individuals. This may cause RIMs over time. |
| Sexual selection methods in sympatric speciation | The preference in mates with specific morphology. |
| Polypoidy in plants method in sympatric speciation | When an organism has more than the normal number of sets of chromosomes. There are two types, autopolyploids and allopolyploids. |
| Autopolyploids | Where a single species double its chromosome number. Two meiotic error where both gamete chromosomes don't reduce. |
| Allopolyploids | Where it produces a sterile hybrid but produce asexually (between two species). Only one meiotic error, hybrid produce asexually reproduces to produce a viable fertile hybrid. |
| Anagenesis | Phyletic evolution where there is a transformation of an unbranched lineage of organisms. |
| Cladogenesis | Branching evolution where there is a budding of one or more species from a parent species that continues to exist. |
| What is the rate of evolution? | It may occur gradually or rapidly. Unmeasurable. |
| What are the 2 models of the rates of evolution? | Gradualism model and the punctuated equilibrium models. |
| Gradualism model | Difficult to find evidence of as there is an incomplete fossil records. |
| Punctuated equilibrium model | Very rapid process with the sudden appearance of a new species.Shown but incomplete fossil records. |
| Extinction | Permanent end of a lineage. |
| Extant | Species that are still alive today. |
| Turn-over species | Where an extinction of a species comes a rise in a new species. |
| What are the 2 rates of extinction? | Background extinction (continuous low level extinctions) and mass extinctions (huge number of species going extinct). |
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theecloud
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