Exam 1 Flashcards
Can natural selection fashion the perfect organism?
no, it only selects on existing variations within a population. Therefore, as the environment is under the influence of the elements it is an everchanging and the organisms which inhabit must change with it to avoid extinction
Diploidy
a cell containing two sets of chromosomes (2n), one set inherited from each parent
What are Darwin’s two observations?
Darwin’s two observations are (1) members of a population vary greatly in their inherited traits and (2) all species can produce more offspring than the environment can support, many of these offspring fail to survive and reproduce.
Correlational relationship
relationships between two events or actions, however this does not mean that one event simply causes another event to occur.
Cause and effect relationship
one event/variable causes an outcome from the other event/variable to occur.`
Which is more rigorous a cause & effect or correlational relationship?
cause-and-effect relationship is more rigorous than a correlation between two variables because a cause-and-effect relationship must be established.
Evolutionary biology
study of evolution, or the study of the process by which species accumulate differences from their ancestors as they adapt to different environments over time.
Father of evolution
Charles Darwin
Natural selection
a process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
Define gene frequency
the percentage of a population that carries allele at a particular locus
Who is Jean-Baptiste De Lamarck and what contributions did they make regarding the development of evolutionary theory?
developed two principles: (1) use and disuse of parts-the idea that parts of the body that are used extensively become larger and stronger, while those that are not used deteriorate. and (2) the inheritance of acquired characteristics-stated that an organism could pass these modifications to its offspring.
Who is Carolus Linnaeus and what contributions did they make regarding the development of evolutionary theory?
developed the binomial naming system for species according to genus and species, which classified species into increasingly complex categories.
Who is James Hutton and what contributions did they make regarding the development of evolutionary theory?
proposed the theory of gradualism-profound geological changes took place through a cumulative effect of slow but continuous processes identical to those currently operating.
Who is Alfred Russel Wallace and what contributions did they make regarding the development of evolutionary theory?
developed and published a theory of natural selection nearly identical to that of Darwin’s, just earlier.
What are the various lines of evidence that support evolutionary change caused by natural selection?
- Although natural selection occurs through interactions between individual organisms and their environment, individuals do not evolve. A population is the smallest group that can evolve over time.
- Natural selection can only act on heritable traits that are passed from organisms to their offspring. Characteristics acquired by an organism during its lifetime may enhance its survival and reproductive success, but there is no evidence that such characteristics can be inherited by offspring.
- Environmental factors vary from place to place and from time to time. A trait that is favorable in one environment may be useless or even detrimental in another environment.
What are the four main mechanisms that contribute to evolutionary change?
(1) homology
(2) fossil record
(3) biogeography
(4) natural selection
Phylogenetic tree
a diagram that represents evolutionary relationships among organisms; they are hypotheses not facts.
Cladogram
diagram that shows the evolutionary relationships among a group of organisms
Significance of nodes in phylogenetic trees and cladograms
represent divergences or speciation events.
What did biogeography contribute to the theory of evolution?
we can use our understanding of evolution and continental drift to predict where fossils of different groups of organisms might be found.
Biogeography
the scientific study to the geographic distribution of species
What did paleontology contribute to the theory of evolution?
fossils show the evolutionary changes that have occurred in various groups of organisms.
Paleontology
the study of extinct species via fossil evidence
What did relative dating contribute to the theory of evolution?
fossils buried in the lower layers are older than those encased in the upper strata, which were formed more recently
Relative dating
method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
What did the law of superposition contribute to the theory of evolution?
within a sequence of layers of sedimentary rock, the oldest layer is at the base and the layers get progressively younger with ascending order in the sequence.
What did radiometric dating contribute to the theory of evolution?
fossils buried in the lower layers are older than those encased in the upper strata, which were formed by more recent deposits.
What did continental drift contribute to the theory of evolution?
movements in the mantle cause the plates to move over time, shifting the continents and the species which inhabit them
A naturally occurring isotope (potassium-40) has a half-life of 1.3 billion years. The original parent isotope weighed 12 mg. The amount of original parent isotope left is 3 grams. What is the age of the rock?
Half-life-the amount of time in which the radioactivity of a radioisotope decreases to half of its original value. Therefore if the original parent isotope weighed 12 mg, after 1.3 billion years, the amount of potassium-40 left would be 6 mg and after another 1.3 billion years later, it would be 3 mg. Therefore, the age of the rock would be 2.6 billion years.
Binomial nomenclature
instituted by Carolus Linnaeus to avoid ambiguity when communicating about research. The first part of the name refers to a species genus to which the species belongs. The second part, called the specific epithet, is unique for each species within the genus.
Classification hierarchy (from species up to Kingdom)
(“King Phillip Came Over For Good Spaghetti”)
The classification of the hierarchy is as follows:
(1) species
(2) genus
(3) family
(4) order
(5) class
(6) phylum
(7) kingdom
Population
a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring
Gene pool
the aggregate of all copies of every type of allele at all loci in every individual in a population