Foundations of Biology chapter 22 and more PDF

Preview

Summary

This is chapter 22 of biology 2 book. Enjoy reading this and read some more. This is redundant....

Description

Chapter 22: Descent with Modification

-Evolution- descent with modification - Evolution can be viewed as both a pattern and a process Rules of Evolution -

Only works on phenotype, and over several generations the genotype will change.

-

Evolution works only at the population level. Individuals do not evolve

-

Variation bc of sexual reproduction

-

Crossing over, independent assortment of alleles, random mutations

Ideas about change over time -

Geologists James Hutton and Charles Lyell perceived that changes in Earth’s surface can result from slow, continuous actions still operating today, and at the same rate.

Lamarck’s Hypothesis of Evolution -

French biologists Jean- Baptiste de Lamarck hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics

-

Unsupported by evidence

Darwin’s Focus on Adaptation -

Adaptation to the environment and the origin of new species as closely related processes.

Artificial Selection -

Modifying other species by selecting and breeding individuals with desired traits, a process called artificial selection.

Observation #1: Members of a population often vary in their inherited traits. Observation #2: All species can produce more offspring that the environment can support, and many of these offspring fail to survive and reproduce.

Inference #1: Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals. Inference #2: This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations.

-

Darwin was influenced by Thomas Malthus, who noted the potential for the human population to increase faster than food supplies and other resources.

Peter and Rosemary Grant Studied many gay species for the past thirty years Evolution is` the change in frequency of an allele, such as a allele for beak depth

Two things that surprised grants 1. Evolution could occur quickly enough to observe within a few field seasons. - Darwin believed that we did not have a long enough lifespan to observe evolution 2. Evolution can occur at very small scales. The grants measurements were very careful 3. Different individuals produce

Key features of natural selection Homology - Homology is similarity resulting from common ancestry - Homologous structures are anatomical resemblance’s that represent variations on a structural theme present in a common ancestor.

Ontogeny Recapitulates Phylogeny - Embryonic development summarizes and reveals our shared ancestry - Comparative embryology reveals anatomical homologies not visible in adult organisms. - For example, all vertebrae embryos have a post anal tail and pharyngeal arches Anatomical and Molecular Homologies - Vestigial structures are remnants features that served a function in the organisms’ ancestors - Ex. Of homologies at the molecular level are genes shared among organisms inherited from a common ancestor. A Different Cause of Resemblance: Convergent evolution - Convergent evolution is the evolution of similar, or analogous, features in distantly related groups - Analogous traits arise when groups independently adapt to similar environments in similar ways. - Convergent evolution does not provide information about ancestry Biogeography - The scientific study of the geographic distribution of species, provides evidence of evolution - Earth was Pangaea

Chapter 23 Genetic Variation - Caused by differences in genes or other DNA segments - Phenotype is the product of inherited genotype and environmental influences - Natural selection can only act on variation with a genetic component Sources of Genetic Variation - New genes and alleles can arise by mutation or gene duplication - Only mutations in cells that produce gametes can be passed to offspring....