Chapter 7 Flashcards
Define mutations
changes in genetic information (that are heritable)
Genetic variation
- all species have genetic variation
- from sexual reproduction and mutations
Neutral mutations + example
- most mutations are neutral
- a mutation that does not result in a selective advantage or disadvantage
- ie. black bears can carry the mutated gene that produces white bears
Harmful mutations + example
- any mutations that reduce the reproductive success of an individual and are therefore selected against; harmful mutations do not accumulate over time
- ie. mutation that leads to genetic disorders
Beneficial mutations + example
- any mutation that increases the reproductive success of an organism; favored by natural selection and accumulates over time
- ie. the sickle cell allele gives carriers a high degree of resistance to malaria and increases their chances of survival in regions with malaria
Define domestication
the changing of members of a species to suit human needs through controlled breeding
Define artificial selection
- directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generational
- used to produce new breeds of varieties of animals and plants
Modern breeding
- using genetic engineering techniques to transfer beneficial genes from an individual of one species to another species
- GMO is then mass produced by cloning
Advantages of selective breeding through artificial selection
- Allows humans to produce animals and crops with desirable traits
- Higher productivity and quality
- Crops can be selectively bred to be resistant to disease
Disadvantages of selective breeding through artificial selection
- Limited by the genetic variability within the breeding population
- Can reduce the overall genetic diversity of the population and contribute to biodiversity loss
Buffon
- Anatomical features that seemed to serve no purpose
- Species must have “improved” and “degenerated” after creation
Carl Linnaeus - Systema Naturae
- Father of modern taxonomy (KPCOFGS)
- Life changed over time
Erasmus Darwin
- Zoonomia
- All warm-blooded animals have arisen from one living filament
- life originates from a single source
Jean-Baptiste Lamarck
- Theory of use and disuse: structures that are used become larger and strong, and structures that are not used become smaller and weaker
- Theory of inheritance of acquired traits: states that individuals could pass on characteristics to their offspring they acquired during their lives
- Lamarck’s theory is flawed
- features do not change in response to use ie. eyes
- characteristics acquired during an individuals lifetime does not change DNA so cannot be inherited
- contributions: all species evolve over time
- A species evolve in response to its environment
- changes are passed on from generation to generation
Fossils
ancient remains, impressions, or traces of an organism or traces of its activity that have been preserved in rocks or other mineral deposits in Earth’s crust
Georges Cuvier
Conducted first detailed studies of fossils
- Fossils from deeper layers were simpler than complex fossils above them
- rock layers contain fossils of many species that do not occur in layers above or below
- a theory that life had evolved from simple to more complex forms over time
- believed that species did not change
- catastrophism: pattern of fossils is by a series of global catastrophes
Charles Lyell
Uniformitarianism: Geological changes are slow and gradual and neutral laws and processes have not changed
Evidence of Evolution
- Biogeography
- Anatomical Features
- Embryology
Biogeography
the scientific study of the geographic distribution of organisms based on both living species and fossils
Darwin’s Hypothesis with the observation of many species of plants, birds, insects, and reptiles from the Galapagos Islands
Only these kinds of organisms are able to reach remote islands by crossing large expanses of open ocean
Darwin’s Hypothesis with the observation of no native amphibians and very few land mammals from the Galapagos Islands
Amphibians and most mammals are unable to cross open ocean and will not be found on remote islands
Darwin’s Hypothesis with the observation of many unique species found nowhere else on Earth from the Galapagos Islands
Over time, ancestral species have evolved into a new geographically isolated species
Darwin’s hypothesis with the observation of unique species most closely resemble species on the nearest continental land mass
Unique species are descendants of ancestral species from the nearest continental land masses and will exhibit some similarites
Homologous structures
- Different function (arm, leg, wing, fin)
Same evolutionary origin / ancestor - divergent evolution
Evolved from same material (bone) to accomplish different tasks
ie. human and cat
Analogous structures
- Same function (ie flight)
- Different evolutionary origin (different common ancestors) - convergent evolution
- different materials to accomplish the same tasks
ie. butterfly wings and bat wings
Vestigial Structures
- unused structures that were useful in a common ancestor but are no longer useful
- not harmful and will be lost over time
- often homologous to structure in a closely related species
ie. wisdom teeth, appendix
Embryology
- closely related organisms go through similar stages during their embryonic development
- groups will diverge to take on distinct characteristics of their classes
- common ancestors
Transitional forms
Fossils or organisms that show the intermediate states between an ancestor and a descendant
- provides evidence for change over time
Molecular biology
- Percentage Similarity in DNA
- similarity in amino acid sequences of particular proteins found in animal species
Natural Selection
- the way nature favors the reproductive success of some individuals within a population over others
- evolution was the result of natural selection over many generations and thousands of years
- populations evolve, not individuals
- produce an unlimited variety of species
Survival of the Fittest + example
- the mechanism of natural selection
- individuals who are best “fit” for the environment at the time will survive and pass on their genes
- if the environment changes, traits that are “most fit” will change
- does not always mean the biggest or strongest
ie. faster cheetahs and stronger lions would have more offspring than slower and weaker individuals of the same species
Adaptation
a characteristic or feature of a species that makes it well suited for survival or reproductive success in its environment
- theory of evolution by natural selection could be extended to every adaptation
Observations and Inferences (1-3) (Mechanism of Natural Selection)
- In each generation, populations produce more offspring than there are adults
- populations do not continue to grow in size
- Food and many other resources are limited
Inference: Individuals within a population compete for resources
Observations and Inferences (4-5) (Mechanism of Natural Selection)
- Individuals within all populations vary
- May variations are heritable
Inference: Some individuals will inherit characteristics that give them a better chance of surviving and reproducing
Theory of Natural Selection
Over time the population changes as advantageous heritable characteristics become more common generation after generation
Evolution of large-billed finches
Birds compete for medium sized seeds, and some large billed birds could feed on larger sized seeds. These larger billed birds have less competition, are healthier, lay more eggs, and offspring will most likely have larger bills. As this process is repeated after generations, number of larger billed birds increase.
