evolution and biodiversity apes chapter 5 ms. miller apes chapter 5 ms. miller
TRANSCRIPT
Evolution and BiodiversityEvolution and Biodiversity
APESChapter 5Ms. Miller
APESChapter 5Ms. Miller
Key ConceptsKey Concepts
Origins of life Origins of life
Evolution and Evolutionary processes Evolution and Evolutionary processes
Ecological niches Ecological niches
Species formation Species formation
Species extinction Species extinction
Origins and Early Evolution of LifeOrigins and Early Evolution of Life
Chemical evolution—evolution on Earth before life (evolution of organic molecules and chemical reactions)
Chemical evolution—evolution on Earth before life (evolution of organic molecules and chemical reactions)
Biological evolution—evolution of living organisms from single cell to multicellular organisms
Biological evolution—evolution of living organisms from single cell to multicellular organisms
Fig. 5-2 p. 88Fig. 5-2 p. 88
Evolution and AdaptationEvolution and Adaptation
Microevolution—small genetic changes that occue in a population
Microevolution—small genetic changes that occue in a population
Macroevolution—long-term, large-scale evolutionary changes by which new species form and others go extinct
Macroevolution—long-term, large-scale evolutionary changes by which new species form and others go extinct
Gene pool—collection of genes or genetic resources potentially available to a population’s offspring
Gene pool—collection of genes or genetic resources potentially available to a population’s offspring
Mutation—random changes in the structure or number of DNA molecules in a cell
Mutation—random changes in the structure or number of DNA molecules in a cell
Natural selection—when individuals have genetic traits that increase their chance of survival and fitness
Natural selection—when individuals have genetic traits that increase their chance of survival and fitness
Natural SelectionNatural Selection
Natural selection is a relatively simple theory that involves five basic assumptions. The theory of natural selection can be better
understood by identifying the basic principles on which it relies. Those principles, or assumptions, include:
Struggle for existence - More individuals in a population are born each generation than will survive and reproduce.
Variation - Individuals within a population are variable. Some individuals have different characteristics than others.
Differential survival and reproduction - Individuals that have certain characteristics are better able to survive and reproduce than other
individuals having different characteristics.
Inheritance - Some of the characteristics that influence an individual's survival and reproduction are heritable.
Time - Ample amounts of time are available to allow for change.
It took thousands of generations to get to this
The result of natural selection is a change in gene frequencies within the population over time, that is individuals with more favorable characteristics will
become more common in the population and individuals with less favorable characteristics will
become less common.
Differential reproduction—selection that enables individuals to leave more offspring than other members of a population
Differential reproduction—selection that enables individuals to leave more offspring than other members of a population
Adaptive trait—any heritable trait that enables organisms to better survive and reproduce
Anthropologist Nina Jablonski, Ph.D. theorizes that variations in human skin are adaptive traits that
correlate closely to geography and the sun’s ultraviolet radiation, not race.
Coevolution—a back and forth adaptation duel between two interacting species in which one species gains a temporary advantage over the other
The relationship between flowering plants and their pollinators can offer a classic examples of coevolutionary relationships. Flowering
plants rely on pollinotors to transport pollen among indivudla plants and thus enable cross-pollination.
Ecological Niches and AdaptationEcological Niches and Adaptation
Fig. 5-4 p. 91Fig. 5-4 p. 91
Ecological niche Ecological niche
Habitat Habitat
Fundamental niche Fundamental niche
Realized niche Realized niche
Broad and Narrow NichesBroad and Narrow Niches
Generalist species—organisms with a broad niche that can live in many places, eat a variety of food and can tolerate wide range of environmental conditions
Generalist species—organisms with a broad niche that can live in many places, eat a variety of food and can tolerate wide range of environmental conditions
Refer to Spotlight p. 92: cockroachesRefer to Spotlight p. 92: cockroaches
Specialist species—organisms with a narrow niche that live in one type of habitat, use one or a few food sources and can tolerate a narrow range of climate and environmental conditions
Speciation, Extinction, and BiodiversitySpeciation, Extinction, and Biodiversity
Speciation—process of forming two species from one Speciation—process of forming two species from one
Fig. 5-7 p. 94
Reproductive isolation—long-term geographic separation of members of a species
Geographic isolation—earth feature blocks interactions of a population thus forming new species
Allopatric Speciation: Parent population of a species is physically
separated and spatially isolated.
Allopatric Speciation: Parent population of a species is physically
separated and spatially isolated.
Each population then takes on a slightly different traits and can, at times, cause such great differences that if the barrier is removed,
they can’t interbreed.
Allopatric speciation of squirrels in the Grand Canyon .
The canyon is a barrier to dispersal by small mammals, and as a consequence the isolated
populations can diverge.
Parapatric Speciation:Population isn’t spatially segregated ; occurs
more in plants.
Parapatric Speciation:Population isn’t spatially segregated ; occurs
more in plants.
Spontaneous genetic abhorations which changes over time and diverge (mutations which survive and reproduce). Ex: number of chromosomes
Reproductive Isolating Mechanisms: work by preventing mating from occuring. The end
result if EXTINCTION…not speciation
Reproductive Isolating Mechanisms: work by preventing mating from occuring. The end
result if EXTINCTION…not speciation
1) Ecological/Spatial Isolation: individuals are separated physically and unable to breed
2) Temporal Isolation: Species have different periods of sexual reproduction2) Temporal Isolation: Species have different periods of sexual reproduction
Example :Drosophila persimilis - breeds in early morning
Drosophila pseudoobscura - breeds in the afternoon
3) Behavioral Isolating Mechanisms: Incompatible behaviors prevent mating from occuring.
3) Behavioral Isolating Mechanisms: Incompatible behaviors prevent mating from occuring.
http://www.youtube.com/watch?v=cEh-zclVo44
4) Mechanical Isolation: Size differences, different reproductive tracts prevent mating from occuring.
4) Mechanical Isolation: Size differences, different reproductive tracts prevent mating from occuring.
5) Mating occurs but offspring are not viablea) die young or before birthb) are sterile
5) Mating occurs but offspring are not viablea) die young or before birthb) are sterile
Liger: male lion and female tiger Tigon: female lion and male tigerLiger: male lion and female tiger Tigon: female lion and male tiger
ExtinctionExtinction Background extinction—when local conditions change
and species disappear at a low rate (annual extinction rate of one to five species for each million species on earth)
Background extinction—when local conditions change and species disappear at a low rate (annual extinction rate of one to five species for each million species on earth)
Mass extinction—a significant rise in extinction rates above the background level; widespread event 25-70% of species wiped out
Mass extinction—a significant rise in extinction rates above the background level; widespread event 25-70% of species wiped out
Adaptive radiation—periods of recovery after a mass extinction
Adaptive radiation—periods of recovery after a mass extinction
Mass depletion—when extinction rates are higher than normal but not high enough to classify as a mass extinction
Mass depletion—when extinction rates are higher than normal but not high enough to classify as a mass extinction
Human Impacts—human activities are decreasing the earth’s biodiversity and are leading towards a mass extinction
Human Impacts—human activities are decreasing the earth’s biodiversity and are leading towards a mass extinction
Human Impacts on EvolutionHuman Impacts on Evolution
Artificial Selection—process by which humans select desirable genes of a population (selective breeding); used in agriculture
Genetic Engineering—(gene splicing)—techniques used to isolate, modify, multiply and recombine genes from different organisms
Concerns about Genetic Engineering—unpredictable process and raises concerns in ethical, legal and environmental practices
Artificial Selection—process by which humans select desirable genes of a population (selective breeding); used in agriculture
Genetic Engineering—(gene splicing)—techniques used to isolate, modify, multiply and recombine genes from different organisms
Concerns about Genetic Engineering—unpredictable process and raises concerns in ethical, legal and environmental practices