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Option D2: Species and Speciation

Option D2: Species and Speciation. Definitions. _________ – all genes in a population at a given time _____ - version of a gene ____________ – the measure of a specific allele in proportion to the entire population Expressed as a proportion or _________

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Option D2: Species and Speciation

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  1. Option D2: Species and Speciation

  2. Definitions • _________– all genes in a population at a given time • _____- version of a gene • ____________– the measure of a specific allele in proportion to the entire population • Expressed as a proportion or _________ • Allele frequency is different than the number of _____________ in a population expressing that allele

  3. Evolution of a species • Evolution of a species involves a change in the ______________of a __________ over several generations • Allele frequencies are only a __________ • __________, __________ or _______________ can occur (cause new entries into gene pool or exits from pool) If suitable for _________, then gene will be passed on (increasing allele frequency) In time, previous less suitable genes will be “________” of gene pool

  4. _________– any group of organisms that can reproduce fertile offspring • Have similar ____________ (lineage) • Have similar ____________________ • ____________ distinct from other organisms • What are some issues with this explanation of a species?

  5. Barriers Between Gene Pools (How to get really weird animals and plants….) • Genetic isolation • ____________________– islands, mountain ranges, etc. • ___________ (reproductive) Isolation- two species whose _______________do not intertwine ( pollen from one type of flower released before pistil of other flowers have emerged) • _______________– mating behavior selects certain characteristics (mating ritual of one organism not seductive enough) Any of these will lead to new __________ given enough time

  6. Speciation • Formation of a new ________ that no longer breeds with the ______________

  7. Allopatric Speciation • When speciation occurs because of _________________ • Islands are a great example of this

  8. Sympatric Speciation • _________ do overlap, but speciation occurs because of another influence (temporal, or behavioral) • Could be mating ________, _______, or other courtship behavior • ex. Mutation of pheremone that only attracts a few females

  9. Polyploidy • Sex cells – __________ • Somatic cells - __________ • ______________ – condition where there are more than 2 homologous chromosomes due to improper cell division • Most common in __________ (makes them hardier) • These extra chromosomes can make them _______________with the original. Can lead to _________ or ____________ of species if more favorable.

  10. Adaptive Radiation • Many similar but distinct species ___________ from one single species • Happens when the organism is ___________ and in a ________ of opportunity • In Darwin’s Finch the beaks adapted for ______ _____________ • Lemurs in Madagascar live in _______________ (desert, trees, ground)

  11. Convergent vs. Divergent Evolution • Divergent is simply speciation due to ____________ to new _____________ (ex. Ancestor squirrel split by grand canyon to White-tailed antelope sq. and Harris’s antelope sq.) • Convergent Evolution is when different organisms evolve _______________ due to similar selective __________ (marsupial anteater in Australia; mammal anteater in S.A. bioluminescence in marine organisms and fungi)

  12. Theories on pace of evolution • ___________ – species slowly change through a series of intermediate forms • Supporters say __________ for enough organisms exist to show these slow _________ changes • Supporters also say that you don’t see most organisms ________________ now

  13. _______________ – rapid speciation due to new niche formation or geographic isolation • Support by fossil record showing organisms (cochroaches, sharks) that have __________ significantly over millions of years • Also supported by ______ in fossil record

  14. Polymorphism • When more than one ________ of a species is present in a population • _________________– one form is distinctly disadvantaged • __________________- if both forms provide a distinct advantage for survival

  15. Transient Polymorphism • Allele frequency changes in response to _____________ • Can change back

  16. Sickle Cell Anemia is balanced polymorphism • In malaria stricken areas – both forms offer a ________ (balanced) • HbA allele codes for blood cells that __________, but susceptible to ___________ • HbS allele can’t carry O2, but __________ to malaria • HbAHbS person gets best of __________ • When not in a location where malaria is endemic, not a suitable characteristic (transient)

  17. Cystic fibrosis • Cf gene causes _______ buildup, but normal gene is susceptible to ________

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