Biology 121 chapter 7
Terms in this set (52)
species changing in a population over time, modern species have descended from common
mechanism of evolution, individuals with variations that make them best suited, will
he accumulation of favorable traits in a population over time
fossils being dated by using their geological position
provides evidence of change w/ in lineages
the study of the geographic distribution of species
units of evolution, a group of individuals of the same species living in the same place at
consist of all versions of all the genes carried by all the individuals in a population
A generation-to-generation change in the gene pool
-which is evolution occurring on its smallest scale
the contribution that an individual makes to the gene pool of the next generation in
comparison to the contributions from other individuals, the fittest individuals are not always the stronges
a change in a gene pool due to chance
a population is drastically reduced in numbers
a few individuals migrate to a new isolated habitat
the genetic exchange among populations due to migration
a form of natural selection that depends on an individual's ability to obtain a mate.
-Females may choosemales for their traits.
-Males may competewith each other foraccess to mates.
encompasses the major changes in history of life, genetic change on a large scale
evolutionary formation of new species
when an ancestral population changes gradually
when an ancestral population splits into two or more populations
floating plates atop a very hot layer of rock called the mantle, their movement rearranges the geography of the continents
The layer of hot, solid material between Earth's crust and core.
derived from a Latin word meaning "appearance."
-a population that is capable of interbreeding to produce healthy, fertile offspring
prevent members of different species from breeding: behavioral isolation, mating
time differences, habitat isolation, mechanical incompatibility, gametic incompatibility, hybrid weakness
Graduated model of speciation
a species acquires small adaptations to its environment over millions of
punctuated equilibrium model of speciation
there are periods of stasis interrupted by occasional burst of
may occur when a physical barrier isolates populations, Grand Canyon
may occur quite suddenly due to large-scale genetic changes, no physical barrier
the identification, naming, and classification of species into domains
Prokaryotes (Domain bacteria, Domain archaea), Eukaryotes (Domain eukarya)
an ordered series of progressively smaller categories (D.K.P.C.O.F.G.S.)
a way to reflect the evolutionary history of organism, presents a hypothesis about the
evolutionary history of related species
any group of species that consists of an ancestral species and all its descendants
analysis of clades
What are the two main points of "On the Origin of Species"?
1. Evolution: modern species have descended from common ancestors
2. Natural Selection: the mechanism of evolution
What are 4 observations Darwin had about the natural world, and what are the 3 conclusions they led
a. Observation: Overproduction- more individuals being born than the environment can support
b. Observation: Limited Resources- the amount of resources stays relatively constant
i. Conclusion: Competition- more offspring than resources, not all individuals
c. Observation: Variation- no two individuals are alike
i. Conclusion: Natural Selection- individuals with variations that make them best suited
d. Observation: Heritability- traits of an organism are likely to be passed down
i. Conclusion: Evolution- because traits are passed, and because more certain members
survive, a pop will change over time becoming better suited to its environment
What are 3 important points to remember about evolution (see slide 11)?
a. Individuals don't evolve, natural selection acts on individuals but only populations evolve
b. Naturals selection works with heritable traits, only genetically coded traits are subject to natural
c. Evolution does not have a goal, it occurs in response to local conditions, not future ones
What are some examples of artificial selection in action in daily life?
a. Dogs and animals
What are some examples of natural selection in action in daily life?
b. Insecticide resistant malaria mosquitoes
c. Herbicide resistant weeds
d. Peppered moths in England
e. Rabbits in Australia
How can the fossil record, biogeography, comparative anatomy, and bioinformatics give evidence of the
evolution of past life on earth?
It is a record of past life that scientist can use to compare, research etc.
How does carbon dating work?
Carbon isotopes decay, carbon can be measures and age calculated
What is the unit of natural selection?
What is the unit of evolution?
What are 2 mechanisms that can cause changes in an individual's genes?
a. Mutations: random changes to DNA which can create new genes
b. Sexual recombination: chromosomes can exchange pieces of DNA (shuffling genes)
What are 4 other mechanisms of that contribute to evolution besides natural selection? How do they
a. Genetic drift- a change in a gene pool due to chance
b. Bottleneck- a population is drastically reduced in numbers
founder effect- a few individuals migrate to a new isolated habitat
c. Gene Flow- the genetic exchange among populations due to migration
d. Sexual selection- a form of natural selection that depends on an individual's ability to obtain a mate
How do branching and non-branching evolution differ? (see definitions)
a. B- splits into two
b. NB- changes over time
How do mass extinctions affect surviving species?
Cause rapid species diversification
How can novel features affect the pace of evolution?
a. Spur large scale evolution, ex. evolutions of feathers and flight in birds
What are the four major geologic eras we discussed, and what is something that happened during each?
a. Precambrian: earth forms, oldest prokaryote fossils, oldest eukaryote fossils
b. Paleozoic: animal diversity in oceans, plant life begins, animals migrate to land, mass extinction
c. Mesozoic: first dinosaurs, flowering plants begin to dominate the land
d. Cenozoic: extinction of dinosaurs, diversification of mammals, appearance of modern humans
How have major geologic changes affected life on earth?
Has split up different species of animals etc. Pangea, plates shifting etc
What are the 6 reproductive barriers that prevent species from successfully interbreeding?
a. Behavioral isolation
b. Mating time differences
c. Habitat isolation
d. Mechanical incompatibility
e. Gametic incompatibility
f. Hybrid weakness
What are 3 types of events that can separate a population into two species?
a. Earthquakes, Mountain building, and Volcanoes
How can phylogenetic trees give insight into evolutionary relationships?
It represents groups of the most recently evolved species to determine how closely related two
species are by finding their most common ancestor