Lab 16
structures that indicate evolutionary relatedness
1. somites 2. pharyngeal pouches 3. postanal tail similarities found among vertebrates
paleontologists estimate that more than _____ of the life forms that ever lived did not form fossils
3/4
why are fossils important to scientists? what scientific evidence do fossils provide?
A fossil is simple a remnant of an preexistent specie (it could be an animal or a plant) which was preserved in sedimentary rocks. Fossils are important in the scientific field because they provide us two different kinds of information. first, they allow us to study the tectonic history. If we find the same fossils extended across different modern continents, it will demonstrate that those continents were connected in the pass. The second piece of information that fossil provides to the scientific community is the history of life. They show us how were the shape and morphology of animals and plants in the past and allow us to make evolutionary conclusions between modern and ancient species.
father of evolution
Charles Darwin
what is the importance of the different beak shapes of Darwin's finches?
Darwin wondered about the changes in shape of bird beaks from island to island. these variations were due to adaptations that the birds had to make in order to adapt to the environment in which they were exposed to, as environmental conditions on each island varied and the finches had to make adaptations to in order to survive and compete with other organisms for food sources. the ability of the finches to adapt so quickly is an example of adaptive radiation. (remember generalists vs. specialists)
How do Darwin's finches reflect adaptive radiation?
Each species of finch had its own distinctive beak and ecological niche. Molecular data suggests that these finches evolved from an ancestral seed-eating, warbler type, "dull colored grassquit" that lived on the mainland. Darwin's finches diverged in response to the availability of food in the different habitats. A research group at Princeton University has shown that a single year of drought on the islands can drive evolutionary changes in the finches. the drought diminishes supplies of easily cracked nuts but permits the survival of plants that produce larger, tougher nuts. Drought thus favors birds with strong, wide beaks that can break these tougher seeds. If droughts occur about once every 10 years, a new species of finch might arise in only 200 years.
who proposed punctuated equilibrium?
Gould and Eldridge
what is the role of natural selection in the process of evolution?
Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population and pass on these inheritable genetic characteristics to their offspring.
Evolution
a change over time in the genetic makeup of a population involves changes in allele frequencies over time (genetic change in time by a change ing genetic makeup of a population, occurs by natural selection)
if the environment changes
an adaptation could become detrimental rather than advantageous
microevolution
changes in a population with a species over time
environments are always
changing
fossil fuels
coal, petroleum, and natural gas are known as fossil fuels because they are the remains of plant and animal matter transformed by bacteria, heat, and pressure. fossil plants and animals are often found imbedded in seams of coal
molecular biologists have studied the amino acid sequences of this protein in order to determine common ancestry. name this protein
cytochrome c. a heme protein found in the mitochondria of many species of single-celled organisms, plants, and animals. consists of a chain of approx. 100 amino acids and functions in the transfer of electrons in the ETC.
absolute dating
dating fossils based on radioactive decay of isotopes (radioactive dating) C14 most common electromagnetism limited to specimens younger than 60,000 yrs
relative dating
dating fossils by their associated time period (based on type of rock using stratigraphy)
dating fossils is important in
determining the geologic time scale
generalists
do not have specific adaptations for a particular trait
methods of dating for specimens older than 60,000 years
fission track dating, paleomagnetism, dendrochronology, amino acid racemization, thermoluminescence, electron spin resonance
many people view evolution as a _______ process
gradualistic
specialists
have specific adaptions of a particular traits
organisms living in water or near water are
likely to be buried in sediment that protects them from mechanical forces and decay
natural selection
mechanism by which species can evolve resulted in organisms with adaptations that make them well-suited to their environment
organisms that have hard parts such as bones, teeth, or shells are _____ ______ to fossilize than organisms with soft parts
more likely
macroevolution
occurs above species level and involves vast amounts of time addresses questions such as how dinosaurs gave rise to birds and how flowering plants originated
what are the three pieces of evidence that support evolutionary history?
paleontological evidence and comparative anatomical evidence, embryological evidence, molecular evidence
study of fossils
paleontology
Three major factors increase the chances of something fossilizing. what are they?
possession of hard parts, escape from immediate destruction, rapid burial.
what are three matrices in which organisms may become fossilized?
possessions of hard parts, escape from immediate destruction (weathering, crushing, wave action, predators, mechanisms of decay), and rapid burial
carbonization
reduce plants and animals to shiny films actually finer than tissue paper
anatomical structures can help indicate
relations among organisms if they share a recent common ancestor
petrification
results from mineral matter soaking into every cavity and pore of a specimen and replacing the living material. hard parts, however, are not totally replaced
sedimentary rock fossilization
sedimentary rocks can contain fossils because they form at temperatures and pressures that do not destroy fossil remains. dead organisms can become trapped in sediments that may become sedimentary rock. ex: limestone formed of shells largely reduced to calcium carbonate
artificial selection
selectively breeding for desired traits
homologous structures
similar anatomical features and embryological development similar evolution
analogous structures
similar function but not a similar evolutionary history/similar anatomy similar habitat
punctuated equilibrium
some species are generally stable and change very little for long expanses of time this period of species stability is "punctuated" by a rapid burst (from a geological standpoint) or a jump that results in a new species that does not leave many fossils in the record ex: fossil records of some mollusk and bryozoan species
vestigial structures
structures that no longer serve a function common ancestry
generalists may have a _______ _______ when conditions change and specialist species are unfit for the new environment
survival advantage
we often hear the statement "survival of the fittest", what does it really mean? how does the environment influence the survival of an organism?
survival of the fittest occurs when organisms with favorable variations of a trait survive, reproduce, and pass their variations onto the next generation. environments are constantly changing, so those who will survive are the best fit to survive.
acidity fossilization / chemical preservation
the acidity (tannic acid) of peat bogs can mummify soft tissues of plants and animals
Adaptive radiation
the process by which a species or group of related species evolves rapidly into many different species that occupy new habitats or geographic zones. rapid evolution due to abundant space and resources, and low competition. evolution is fueled by a changing environment and the response of change in an organism's genetic information
fossil
the remains, or traces, of organisms that lived in the past
replacement
total replacement of original structures often lack details
fossilized in amber
tree sap may have trapped insects, feathers, or other biological specimens and preserved them in a permanent encasement
fossils can help us to
understand pattens of diversity and the relative age of different organisms
the remains of most organisms are destroyed by mechanical forces or biological actions such as
weathering, crushing, wave actions, and predators, scavengers, mechanisms of decay
