Chapter 18 Flashcards
Heritable change in a population over time. Describes a mechanism for how species change over time. Change in populations inherited traits over time. Populations do this but not individuals.
Evolution
Conceived the actual mechanism for evolution. Observed on his travels that the species were clearly similar, yet had distinct differences.
Ex.) The ground finches comprised of several species with a unique beak shape. He observed that these species had various beak sizes and shapes with very small differences between the most similar. He observed those finches resembled other ones on South African mainland. He believed the island species might be modified from one of the original mainland species.
Charles Darwin
Leads to evolutionary change. Process in which individuals with favorable inherited traits are more likely to survive and reproduce. “survival of the fittest.” Reproduction of individuals with favorable traits that are able to survive environmental change because of those traits.
Natural Selection.
When can natural selection only take place:
- can only take place if there is variation (differences) among individuals
- must have genetic basis– because selection will not lead to chance in next generation if so.
Genetic diversity comes from:
1.) Mutation
2.) Sexual Reproduction
A change in DNA, is the ultimate source of new alleles, or new genetic variation in any population. Affects organisms phenotype: reduces or benefits fitness (may also have no effect) , lower likelihood of survival
Mutation
Leads to diversity when 2 parents reproduce, unique combos of alleles assemble to produce the unique genotypes and thus phenotypes in each offspring.
Sexual reproduction
A trait with a current functional role in life of an organism that is maintained and evolved by means of natural selection. Heritable trait that helps an organisms survival and reproduction in its present environment.
Adaptation
Observation of Evolution:
1.) Direct Observations
2.) Homology
3.) Convergent Evolution
4.) The fossil record
5.) Biogeography
Two examples provide evidence for natural selection: natural selection in response to introduced species and the evolution of drug-resistant bacteria. ex.) Florida lizard
Direct Observations
Similarity resulting from common ancestry.
Homology
anatomical resemblances that represent variations on a structural theme present in a common ancestor.
Homologous structures
Are remnants of features that served important functions in the organisms ancestors. Unused structures without function. Ex.) wings on flightless birds, leaves on cacti, and hind leg bones on whales.
Vestigial structures
Where similar traits evolve independently in species that do not share a recent common ancestry. The evolution of similar or analogous features. in distantly related groups. Ex.) bat and insect wings have evolved from very different original structures. The trait in the two species came to b similar in structure and have the same function (flying) but did so separately from each other.
ex.) Artic fox and ptarmigan live in artic region, have white phenotype, do not occur from common ancestry. Just a benefit of predators not seeing them.
Convergent Evolution
Traits arise when groups independently adapt to similar environments in similar ways. When similar characteristics occur because of environmental constraints and not due to a close evolutionary relationship.
ex.) Insects use wings to fly like bats and birds, but the wing structure and embryonic origin are completely different.
(these are still homologous remember! but while wings are these…)
Analogous (homoplasy)
Groups of organisms that become tremendously different from each other. 2 species that evolve in diverse direction from a common point. ex.) The reproduction of flowering plants share same basic anatomies; however they can look very different as a result of selection in different physical environments and adaptations to different kinds of pollinators.
Divergent Evolution
The extinction of species. The origin of new groups. Changes within groups over time.
Fossil Records
The scientific study of the geographic distribution of species. Pangea–Geographically separated species.
Biogeography
species that are not found anywhere else in the world. basis from biogeography. evolution occurs in different location and not found anywhere else other than that different location.
Endemic
Process by which one species splits into two or more species.
Speciation
Consists of change in allele frequency in a population over time.
Microevolution
Refers to broad patterns of evolutionary change above the species level.
Macroevolution
Myths of Evolution:
- Evolution is just a theory
- Individuals evolve (they don’t)
- Evolution explains the origin of life
- Organisms evolve on purpose
Definitions of Species include:
1.) Biological Species Concept
2.) Morphological Species Concept
3.) Ecological Species Concept
4.) Phylogenetic Species Concept
A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.
Biological Species Concept
the existence of biological barriers that impede two species from producing viable, fertile offspring. Sometimes hybrids (a cross between 2 species), the offspring of crosses between different species, are successfully produced.
Reproductive Isolation
Block fertilization from occurring.
ex.) species of flower in Europe and zygote does not occur. What pat of this makes the effect?
Prezygotic Barriers
habitat
Prezygotic Barriers block fertilization from occurring by:
- Impeding different species from attempting to mate
- Preventing successful completion of mating
- Hindering fertilization if mating is successful
Examples of prezygotic barriers:
Habitat, temporal, behavioral, mechanical, and gametic
Prevent the hybrid zygote from developing into a viable, fertile adult.
ex.) mule is made but cannot reproduce itself.
Postzygotic Barriers
Postzygotic Barriers prevent the hybrid zygote from developing into a viable, fertile adult by:
- Reduced hybrid viability
- Reduced hybrid fertility
- Hybrid breakdown
- A horse and a donkey mate and fertilize to make a mule(hybrid). Usually mules cannot reproduce. If an offspring does result, it cannot reproduce.
Defines a species by structural features. Look alike in structure.
Morphological Species Concepts
Views a species in terms of its ecological niche. job in environment, where they live, where they eat.
Ecological Species Concept
Defines a species as the smallest group of individuals that share a common ancestor, a single branch on a phylogenetic tree. Ancestry, relation from DNA
Phylogenetic species concept
Speciation can occur in 2 ways:
1.) Allopatric Speciation
2.) Sympatric Speciation
“other homeland”. Gene flow is interrupted when a population is divided into geographically isolated subpopulations. Separate populations may evolve independently through mutation, natural selection, and genetic drift.
Allopatric Speciation
part of allopatric speciation. When a few members of a species move to a new geographical area.
Dispersal
part of allopatric speciation. When natural situation arises to physically divide organisms.
vicariance
“same homeland.” Takes place in populations that live in the same geographic area.
sympatric “same country” speciation
Occurs during the time course of speciation. What includes examples of species that appear suddenly, persist essentially unchanged for some time, and then disappear?
Fossil Record
Occurs during the time course of speciation. They are periods of apparent stasis punctuation by sudden change. The punctuated pattern in the fossil record and evidence from lab studies suggest that speciation can be rapid.
punctuated equilibria or punctuated equilibrium
Occurs from events of speciation and extinction. Is large scale evolutionary change resulting from the cumulative effect of many speciation and extinction events.
Macroevolution
Members of the same species can breed together and produce viable offspring in the ____________ species concept.
a.) morphological
b.) biological
c.) ecological
d.) phylogenetic
b.) biological
Habitat isolation is a ________ zygotic barrier that keeps species separate.
a.) post
b.) pre
b.) pre
Hip bones in whales and snakes are examples of
a.) vestigial structures
b.) convergent evolution
c.) biogeography
d.) pre zygotic barrier
a.) vestigial structures
Gliding has evolved independently in sugar gliders and flying squirrels. In this example gliding is a/an:
a.) homology
b.) vestigial structure
c.) analogous trait/structure
d.) endemic
c.) analogous trait/structure
True or False?
New species evolve in the same geographic area in sympatric speciation.
True
If two species eat a different diet but one of the food sources is eliminated and both species are forced to eat the same foods, what change in the hybrid zone is most likely to occur?
Fusion because the two species will interact more and similar traits in food acquisition will be selected.
Which of the following statements is false?
A.) Punctuated equilibrium is most likely to occur in a small population that experiences a rapid change in its environment.
B.) Punctuated equilibrium is most likely to occur in a large population that lives in a stable climate.
C.) Gradual speciation is most likely to occur in species that live in a stable climate.
D.) Gradual speciation and punctuated equilibrium both result in the evolution of new species.
B.) Punctuated equilibrium is most likely to occur in a large population that lives in a stable climate.
Which scientific concept did Charles Darwin and Alfred Wallace independently discover?
a.) mutation
b.) natural selection
c.) overbreeding
d.) sexual reproduction
b.) natural selection
Which of the following situations will lead to natural selection?
a.) The seeds of two plants land near each other and one grows larger than the other.
b.) Two types of fish eat the same kind of food, and one is better able to gather food than the other.
c.) Male lions compete for the right to mate with females, with only one possible winner.
d.) all of the above
d.) all of the above
Which description is an example of a phenotype?
a.) A certain duck has a blue beak.
b.) A mutation occurred to a flower.
c.) Most cheetahs live solitary lives.
d.) both a and c
d.) both a and c
Which situation is most likely an example of convergent evolution?
a.) Squid and humans have eyes similar in structure.
b.) Worms and snakes both move without legs.
c.) Some bats and birds have wings that allow them to fly.
d.) all of the above
d.) all of the above
Which situation would most likely lead to allopatric speciation?
a.) Flood causes the formation of a new lake.
b.) A storm causes several large trees to fall down.
c.) A mutation causes a new trait to develop.
d.) An injury causes an organism to seek out a new food source.
a.) Flood causes the formation of a new lake.
What is the main difference between dispersal and vicariance?
a.) One leads to allopatric speciation, whereas the other leads to sympatric speciation.
b.) One involves the movement of the organism, and the other involves a change in the environment.
c.) One depends on a genetic mutation occurring, and the other does not.
d.) One involves closely related organisms, and the other involves only individuals of the same species.
b.) One involves the movement of the organism, and the other involves a change in the environment.
Which variable increases the likelihood of allopatric speciation taking place more quickly?
a.) lower rate of mutation
b.) longer distance between divided groups
c.) increased instances of hybrid formation
d.) equivalent numbers of individuals in each population
b.) longer distance between divided groups
Which reproductive combination produces hybrids?
a.) when individuals of the same species in different geographical areas reproduce
b.) when any two individuals sharing the same habitat reproduce
c.) when members of closely related species reproduce
d.) when offspring of the same parents reproduce
c.) when members of closely related species reproduce
Which condition is the basis for a species to be reproductively isolated from other members?
a.) It does not share its habitat with related species.
b.) It does not exist out of a single habitat.
c.) It does not exchange genetic information with other species.
d.) It does not undergo evolutionary changes for a significant period of time.
c.) It does not exchange genetic information with other species.
Which situation is not an example of a prezygotic barrier?
a.) Two species of turtles breed at different times of the year.
b.) Two species of flowers attract different pollinators.
c.) Two species of birds display different mating dances.
d.) Two species of insects produce infertile offspring.
d.) Two species of insects produce infertile offspring.
Which term is used to describe the continued divergence of species based on the low fitness of hybrid offspring?
a.) reinforcement
b.) fusion
c.) stability
d.) punctuated equilibrium
a.) reinforcement
Which components of speciation would be least likely to be a part of punctuated equilibrium?
a.) a division of populations
b.) a change in environmental conditions
c.) ongoing gene flow among all individuals
d.) a large number of mutations taking place at once
c.) ongoing gene flow among all individuals
Which is the appropriate written out scientific name?
a.) canis
b.) canis lupus
c.) wolf
d.) canis lupus familian’s
b.) canis lupus
Related but not the same species:
canis lupus and canis domisticus
Classification order in most general to most specific (put in order):
order, family, phylum, species, class
phylum, class, order, family, species
evolution that occurs quickly
punctuated equilibrium
New species evolve gradually over time
gradual model
