IB Bio HL A4.1

_______ speciation occurs due to geographical isolation: the physical separation of two populations of the same species.

Allopatric speciation occurs due to geographical isolation: the physical separation of two populations of the same species

_______ speciation occurs when a population divides into different species while inhabiting the same habitat. There is no geographical isolation.

Sympatric speciation occurs when a population divides into different species while inhabiting the same habitat. There is no geographical isolation.

Behavioral and temporaly isolation are types of ____ isolation

Behavioral and temporaly isolation are types of sympatric isolation

____ _____ is the evolution of a single ancestral species into several species, as the ancestral species spread out and become adapted to new environmental niches. This results in _____ evolution.

Adaptive radiation is the evolution of a single ancestral species into several species, as the ancestral species spread out and become adapted to new environmental niches. This results in divergent evolution.

Hybrid _____ - Offspring are produced, but do not survive to become sexually mature adults.

Hybrid inviability - Offspring are produced, but do not survive to become sexually mature adults.

Hybrid ______ - Hybrid individuals are produced, but they are not capable of producing functioning gametes. The hybrid is sterile, due to the genetic incompatibility between the two species.

Hybrid infertility - Hybrid individuals are produced, but they are not capable of producing functioning gametes. The hybrid is sterile, due to the genetic incompatibility between the two species.

Hybrid ______ - The first generation of hybrids are capable of reproducing, but their offspring are not able to reproduce.

Hybrid breakdown - The first generation of hybrids are capable of reproducing, but their offspring are not able to reproduce.

_____ organisms have more than two sets of chromosomes in their cells.

Polyploid organisms have more than two sets of chromosomes in their cells.

Polyploid plants with an uneven number of sets of chromosomes (3n, 5n, 7n ...) are ____, as not all of the chromosomes can form homologous pairs during meiosis. Many of these plants can reproduce asexually.

Polyploid plants with an uneven number of sets of chromosomes (3n, 5n, 7n ...) are sterile, as not all of the chromosomes can form homologous pairs during meiosis. Many of these plants can reproduce asexually.

List 3 pieces of evidence for evolution on the IB Biology course:

1.

2.

3.

DNA, RNA and protein sequences.

Homologous structures.

Selective breeding.

_______ suggested that variation exists within a population. Nature selects the individuals with the traits best adapted to survival and reproduction. The favourable traits are passed on to the offspring, causing evolution over time.

Darwin (and Wallace) suggested that variation exists within a population. Nature selects the individuals with the traits best adapted to survival and reproduction. The favourable traits are passed on to the offspring, causing evolution over time.

______ limbs are homologous structures. All organisms with these limbs have evolved from a common ancestor.The structure of the limb is similar in all species but has evolved modifications for a variety of purposes.

Pentadactyl limbs are homologous structures. All organisms with these limbs have evolved from a common ancestor.The structure of the limb is similar in all species but has evolved modifications for a variety of purposes.

Evolution is change in the ______ characteristics of a population over time.

Evolution is change in the heritable characteristics of a population over time.

_____ suggested that organisms acquire traits when they are alive. These acquired traits are beneficial for survival, and can be passed onto offspring, causing evolution over time.

Lamarck suggested that organisms acquire traits when they are alive. These acquired traits are beneficial for survival, and can be passed onto offspring, causing evolution over time.

______ related species have very similar gene and protein sequences, as there will be a small number of mutations because they diverged from a common ancestor.

closely related species have very similar gene and protein sequences, as there will be a small number of mutations because they diverged from a common ancestor.

____ _____ is the process of humans choosing plants or animals with desirable traits to breed together and produce offspring with more of those desirable traits.

Selective breeding is the process of humans choosing plants or animals with desirable traits to breed together and produce offspring with more of those desirable traits.

_____ structures are similar in structure, but may have different functions.

Homologous structures are similar in structure, but may have different functions.

_____ structures are present in organisms that have descended from a common ancestor as a result of evolution.

Homologous structures are present in organisms that have descended from a common ancestor as a result of evolution.

______ evolution is the evolution of similar structures in species not related due to a recent common ancestor.

Convergent evolution is the evolution of similar structures in species not related due to a recent common ancestor.

______ structures have a common function, but do not have a common structure.These structures evolve by ______ evolution.

Analogous structures have a common function, but do not have a common structure.Analogous structures evolve by convergent evolution.

Give an example of analogous structures

bird, bat and insect wings

___-zygotic isolation occurs before fertilization

pre-zygotic isolation occurs before fertilization

___-zygotic isolation occurs after fertilization

post-zygotic isolation occurs after fertilization

Mules are an example of ___-zygotic isolation

Mules are an example of post-zygotic isolation

Explain how a common ancestor evolved into chimpanzees and bonobos.

Chimps/Bonobos are an example of geographic isolation.

Once the Congo river rose, the different populations of the common ancestor of both apes were separated, and each side faced different selective pressures (differential selection)

Since there was a geographical barrier between the two populations, they could no longer mate (prezygotic isolation) and are today considered different species