ENWC201 Study Guide - Final Guide: Sympatric Speciation, Allopatric Speciation, Logistic Function

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chocolatecod698

22 May 2018

School

University of Delaware

Department

Entomology and Wildlife Conservation

Course

ENWC201

Professor

Kyle Mc Carthy

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ENWC 201:

Cumulative Concepts to Review for Final Exam

Section 1: General Wildlife Ecology

● What is an animal’s niche? How many dimensions can a niche have? Can animals share

a niche?

○ The functional role of an organisms considered in the environment in which it

loves

○ Its “job”

○ A niche is multidimensional

■ Time of hunting

■ Size of prey

■ Location of prey

○ Competitive exclusion theory

■ No two organisms can occupy the same niche at the same time in the

same place

■ The more similar the organisms are, the more intense the competition

between them

■ The less-fit species will have to evolve into a dif niche, move to a dif area,

or become extinct

○ How do organisms adapt to fill a particular niche

● Natural selection and evolution

● Darwin

● Natural selection - process that determines which individuals will pass on

their genes to next generation

● Evolution - changes that we see in the genes and characteristics

displayed by successive generations of a population

● Steps of a natural selection

○ Individuals within a species show genetic variation

○ Organisms reproduce many more offspring than are needed to

replace the parents

○ Excess numbers of individuals result in a shortage of resources

○ Individual variation allows some a greater chance of obtaining

resources, and therefore a greater chance of reproducing than

others

○ Over time, each generation is subjected to natural selection. The

percentage of individuals showing favorable variations will thus

increase and those having unfavorable variations will decrease

● Natural selection over time can lead to considerable change in the

characteristics of a species and kinds of species present

● Speciation - the production of a new species from a previously existing

species

○ Allopatric speciation - geographic speciation, speciation that

occurs when biological populations of the same species become

isolated from each

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■ Volcano

■ Most common across time

○ Sympatric speciation - when species are in same area but still

manage to speciate and become different species - because of

available niche space

■ Have to have something special occur

● What happens when a species cannot adapt as fast as environment?

○ Extinction - loss of an entire species

○ 500 million species are believed to have existed

○ 5-10 million are currently in existence

○ Extinctions are a natural result of natural selection, but the

extinction rate is increasing with humans

● Interactions between organisms

○ Predator and prey

○ Predation - one organism known as predator, kills and eats other

organisms, known as they prey

■ Predator Employ strategies to make them more effective at

capturing prey

■ Prey employ strategies to make them more effective at

avoiding predators

■ The relationship between the two is evolving

■ Prey adapt

● Increased reproduction rate

● Tolerate a higher level of mortality

■ Prey that survive pass on their survival traits to their

offspring

■ Predators that are successful in capturing prey, survive

and pass those traits onto offspring

○ Interspecific competition - competition between members of

different species

○ Other symbiotic relationships - long standing physical relationship

between two different species

■ Parasitism - one organisms, known as the parasite lives on

or in another organism known as the host from which it

derives nutrients to the detriment of the host

● Ectoparasite - lives on the outside or surface of the

host

● Endoparasite - lives inside the host

■ Commensalism - relationship between organisms where

one benefits and the other organism is not affected

● Cow and cattle egrets (eats the bugs on the cows)

● Shark and small fish, small fish swims under the

shark and eats whatever comes out of the sharks

mouth after shark eats

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■ Mutualism- both species involved in the relationship

benefit. Many times the relationship is obligatory, meaning

that the species cannot live without each other

● Clownfish and sea anemone

● What is a specialist vs a generalist?

○ Specialist- fit into their environment tightly and there is no room for dealing with

changes or for colonizing different habits. they are good at ONE SPECIFIC

THING

○ Generalist - those adapted to a wide range of environmental circumstances and

food sources

● What is logistic growth? What limiting factors might lead to a given (K) carrying capacity?

○ Carrying capacity (K)

■ The max sustainable pop

■ Limiting factors help define K

■ May change

■ K= carrying capacity

○ Logistic growth rate

○ Our biggest limiting factor of population growth is growing food for ourselves - to

overcome carrying capacity is make new ag advancements

○ Pesticides

○ Managing Animal Abundance

● today hunters and trappers are the cornerstones of NA wildlife

conservation bc of the funds and advocacy they bring the table - they are

the most effective logistical agents of actual population management

● With initial protections, populations became overpopulated and some

efforts were too successful in some cases - the local populations had

been allowed to exceed the carrying capacity

○ Reproduction decreased and mortality increased because of

intraspecific competition for resources available

● Often needed to maintain wildlife populations below environmental and

social carrying capacity to reduce die offs to provide for more productive

populations - to protect die offs, provide more productive populations,

protect habitats and reduce spread of disease or reduce conflicts with

humans

● Biological carrying capacity is normal carrying capacity - social carrying

capacity depends on many factors like conflicts with humans

● What is the energy pyramid? What is at the bottom? What is at the top? Where is the

most energy and the least energy? Where is the most biomass and least biomass?

Where is the highest number of individuals and lowest number?

○ About 1% of sun’s energy is caught and changed into chemical energy

○ Producers (P=1%) -> primary consumers (P=16.2%) -> secondary consumers

(P=11.37%) -> tertiary consumers (P=5%) -> bacteria/ fungus - can eat on all

levels (P=24.3%)

○ Can average out that each level is 10% of the energy of the last

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Document Summary

The functional role of an organisms considered in the environment in which it loves. No two organisms can occupy the same niche at the same time in the same place. The more similar the organisms are, the more intense the competition between them. The less-fit species will have to evolve into a dif niche, move to a dif area, or become extinct. How do organisms adapt to fill a particular niche. Natural selection - process that determines which individuals will pass on their genes to next generation. Evolution - changes that we see in the genes and characteristics displayed by successive generations of a population. Organisms reproduce many more offspring than are needed to replace the parents. Excess numbers of individuals result in a shortage of resources. Over time, each generation is subjected to natural selection. Natural selection over time can lead to considerable change in the characteristics of a species and kinds of species present.

Related Questions

As temperatures in an African savanna increase and rainfall decreases, it would most likely change into

tiaga

desert

tropical rainforest

temperate forest

What is imprinting? Give an example.

fixed assocation, such as hatching ducks recognizing the first animal they see as their mother

a learned behavior, such as a wasp circling during a search for food, so that it can return to its nest

alteration of instinct, such as a spider changing the type of web it weaves depending upon the environment

Opportunistic species

provide extensive care for their offspring

produce many offspring

reproduce later in life

What are the five agents of microevolution?

gamete production; mating; fertilization; caring for offspring; formation of herds

photosynthesis; respiration; mitosis; meiosis; fertilization

mutation; gene flow; nonrandom mating; genetic drift; natural selection

Microevolution is

new species

minor extinction of species

changes in allele frequency in a population

Which of the following is does not help defend against predators?

Toxins made by plants that injure caterpillars feeding on the plant

The large eyespots on a moth's wing that can startle a hungry bird

Thorns on a plant

Many plants have brightly colored fruit and flowers

Humans have a favored birth weight, neither too small nor too large. This is

stabilizing selection

disruptive selection

artificial selection

directional selection

What is a keystone species?

the first organism that populates an area

an organism upon which the entire ecosystem depends

the first fossils found in the earliest rock strata

As temperatures in the Arctic warm, which of the following changes may occur?

Tundra will be replaced by taiga

Taiga will be replaced by tundra

Temperate forest will be replaced by taiga

Tundra will be replaced by desert

Taiga will be replaced by temperate rain forest

What is desertification?

restoration of vegetation and water to deserts

areas adjacent to deserts also become deserts

abandonment of a habitat by animals

Evolution occurs at the level of

individuals

populations

communities

The maximum population that the environment can support is called the

biotic potential

environmental resistance

carrying capacity

replacement reproduction

demographic transition

A population with relatively more pre-reproductive individuals is common in _____-developed countries

less

Endangered species sometimes breed in captivity. Why are such species endangered in the wild?

Their population density is too high

Loss of habitat

Their environment is polluted

Abiotic components of an ecosystem include

only animal life

only plant life

living components only

nonliving components only

both living and nonliving components

Carbon returns to the atmosphere

as carbon dioxide

from respiration of plants

by the burning of fossil fuels

from respiration of animals

All of the answer choices are correct

Why does the Tropical Rain Forest contain an abundance of antibiotic compounds?

The area is crowded, leading to random production of useful compounds

The area is wet. plants had to develop resistance to fungi and bacterial infections

There is a great diversity of plants, leading to random production of useful compounds

The carrying capacity of the environment for a species is determined by

the reproductive rate of the organism

the number of organisms of that species

the state and national wildlife laws pertaining to that species

a complex

the limited productivity of the environment and the environmental resistance to the biotic potential of the organism

An introduced species that breeds and spreads is

resourceful

harmful

native

dominant

invasive

What is disruptive selection?

environmental influences that select against change

environmental influences that promote one phenotype versus all others

environmental influences that promote two or more phenotypes versus all others

Natural selection acts on

individuals

populations

communities

Two populations of birds live in the same area but have different sleep/wake cycles. This is

behavorial isolation

mechanical isolation

geographical isolation

temporal isolation

An insect that resembles the face of a snake avoids predation by

camouflage

warning coloration

mimicry

chemical defense

mutualism

Unselfish acts that help others in a group so that they increase their chances of surviving and reproducing is called

imprinting

mimicry

altruism

learning

instinct

If an environment changes rapidly, organisms with ____ will be more likely to survive and reproduce.

the correct allele frequency

existing neutral mutations

existing beneficial mutations

How did geology influence Darwinâs thoughts?

It demonstrated that the earth was very old, therefore there was enough time for species to evolve

it demonstrated that all continents were similar

it demonstrated the presence of many fossils

The founder effect occurs when

large groups of individuals leave their home population and establish new settlements, mating only among themselves

many members of a population die, resulting in a great loss of genetic diversity

many members of a population reproduce causing too much genetic diversity within the population

small groups of individuals leave their home population and establish new settlements, mating only among themselves.

The greenhouse effect is due to high atmospheric

Nitrogen

Ammonia

Carbon monoxide

Carbon dioxide

Oxygen

What are the Reproductive Barriers that keep species separate?

lack of food; lack of habitat; lack of potential mates; lack of nesting sites; lack of genetic variation

mountains; canyons; glaciers; bodies of water (for terrestrial animals); areas of land (for aquatic animals)

habitat isolation; temporal isolation; behavioral isolation; mechanical isolation; gamete isolation

What is directional selection?

environmental influences that select against change

environmental influences that promote one phenotype versus all others

environmental influences that promote two or more phenotypes versus all others

Which of the following is correct when describing a predator-prey cycle?

A decline in the numbers of predators causes a decline in the number of prey

A decline in the numbers of prey causes a decline in the number of predators

An increase in the number of predators triggers an increase in the number of prey

An up-and-down cycle will be seen for the prey animal

A seasonal die-off that will occur without the other species present

Why are top-level predators (lions, eagles, humans) so rare in a community?

Only a small amount of the energy is passed from one trophic level to the next

They do not breed as fast as other animals

Because of predation by higher predators

It is difficult for them to learn how to capture prey

Their job is to keep the population size of other animals in check

Alleles conferring bright color to male guppies are common because

they make males less visible to predators

they help males identify each other

they are preferred by females

Organisms that obtain their energy from producers or other consumers are

autotroph

heterotroph

producer

autotroph and producer

heterotroph and producer

What is the environmental impact of strip mining?

lack of trees exposes the surface of the earth, promoting runoff and loss of adjacent trees

removal of minerals from the soil hampers growth of vegetation

it causes a potential increase in volcanic activity

Two populations of squirrels are separated by a mountain range and would not be capable of interbreeding. This is an example of:

behavorial isolation

mechanical isolation

geographical isolation

temporal isolation

What is a danger of overfishing?

humans will become dependent upon fish

selection for smarter fish that can avoid being caught

driving the population back into the lag phase

What is meant by prezygotic versus postzygotic speciation mechanisms?

before versus after formation of a zygote

before versus after meiosis

before versus after gamete formation

The relatively short term changes in allele frequencies within a species or population is

artificial selection

microevolution.

speciation

macroevolution

Avoidance of a location with predators is the result of

imprinting

mimicry

altruism

learning

instinct

What is the difference between Density-Dependent and Density-Independent Factors on populations?

density-dependent factors exert a greater influence when there are more individuals; density-independent exerts the same influence on all individuals regardless of their number

density-dependent factors exert a greater influence on larger, more dense individuals; density-independent factors exert the same impact on individuals of all size

density-dependent factors exert the same influence on all individuals regardless of their number; density-independent factors exert a greater influence when there are more individuals regardless of their number

All of the organisms in a given location or area is termed a

peer group

flock

community

population

herd

The concentration of the pesticide DDT would be highest in

a minnow

a mosquito larva

a seagull

plankton

algae

Our biosphere is

the Earth

the atmosphere

the ocean

land on Earth

fresh and salt water

What is meant by âcarrying capacityâ?

the amount of food produced in an ecosystem

the extent of energy required to maintain an ecosystem

the number of individuals that can be supported by an ecosystem

Species living on another is

resource partitioning

coevolution

symbiosis

predation

niche sharing

One species feeding on another is

competition

a community

an ecosystem

predation

symbiosis

Populations of different species interacting with one another in a natural environment is called

competition

a community

a biome

predation

symbiosis

Which of the following is not a biogeochemical cycle?

ATP cycle

water cycle

carbon cycle

phosphorus cycle

nitrogen cycle

Horses became larger and faster to escape predators. This is

stabilizing selection

disruptive selection

artificial selection

directional selection

1.. Polymorphisms for a given trait are relatively common in most species. Discuss the possible advantages or polymorphisms in terms of evolutionary fitness. Be sure to relate your discussion to a specific example. It is also possible that organisms showing more heterozygosity may actually be less fit. Describe one such possible scenario.

2. In the peppered moth (Biston betularia), black individuals may be either homozygous (A1A1) or heterozygous(A1A2), whereas the pale gray moths are homozygous (A2A2). Suppose that in a sample of 250 moths from one locality, 108 are black, and 142 are gray.

3. Retrace the history of primate evolution from early primates to monkeys, apes and hominins. When did some ofthe significant divergences occur (such as between the prosimians and the monkeys or between the chimps and hominins)? What was happening with the continents and the major climatic conditions during these times?What are the major species (including the extinct species) along the human lineage after the split with the chimps and bonobos? Where did many of these events occur on the globe and when?

4. Spencer Wells described his study how the genetic markers in humans are being used to infer the historical geographical distribution of humans and the dispersal of our ancestors. Explain how the genetic markers on our DNA (from blood samples) helps us understand that history. What are the techniques he is using? What is the nature of the evidence? What are the major conclusions about the journey of our ancestors out of Africa?What were the major migrations of humans to all the other continents? Approximately when did each migration occur and what were the major paths? How does the evidence support these conclusions? What Supporting evidence besides the DNA evidence is being used to support these conclusions?

5. Provide an adaptive and a non adaptive hypothesis for the evolutionary loss of useless organs, such as eyes in many cave-dwelling animals. How might these hypotheses be tested?

6. Directional selection is one of the models of natural selection. Describe this type of selection in terms of the frequencies of advantageous alleles over time. What is the trend over time? What is the eventual outcome for this allele as long as no other evolutionary factors intervene? Describe at least one good example of directional selection.

7. Consider the first copy of an allele for insecticide resistance that arises by mutation in a population of insects exposed to an insecticide. Is this mutation an adaptation? If, after some generations, we find that most of the population is resistant, is the resistance an adaptation? If we discover genetic variation for insecticide resistance in a population that has had no experience of insecticides, is that variation an adaptation? If an insect population is polymorphic for two alleles, each of which confers resistance against one of two pesticides that are alternately applied, is that variation an adaptation? Or is each of the two resistance traits an adaptation?Explain your reasoning thoroughly.

8. Suppose that a mutation in a species of annual plant increases allocation to chemical defenses against herbivores, but decreases production of flowers and seeds (i.e., there is an allocation trade-off). What would you have to measure in a field study in order to predict whether or not the frequency of the mutation will increase?

9. In many socially monogamous species of parrots and other birds, both sexes are brilliantly colored or highly ornamented. Is sexual selection likely to be responsible for the coloration and ornaments of both sexes? How can there be sexual selection in pair-bonding species with a 1:1 sex ratio, since every individual presumably obtains a mate? Which of the models of sexual selection described in the book might account for these species characteristics?

10. Kin selection explains why organisms may provide benefits to relatives. Is there a conflict between the principle of kin selection and the evolution of siblicide and abortion?

11.Many species of albatrosses and other seabirds nest in colonies on islands. The adult search for food at sea,sometimes over great distances. Some ecologists who study seabirds turn to their favorite topic of discussion in a bar one evening, and one says, âI can imagine an albatross genotype that destroys the eggs of nestlings of its colony mates when the parents are away foraging, and leaves them dead without eating them. Do you think such a behavior would evolve?â One of his companions says, âYes, because it would make more food available for the albatross and its offspring.â Another says, âNo, because it would threaten the survival of the population.â The fourth says, âYouâre both wrong. I have a different explanation for why albatrosses donât kill othersâ chicks.â What is the fourth ecologistâs explanation, and why does she think her companions are wrong?

12. The concept of a species is fundamental to understanding biology, yet there may not be one definition that fits all âtypesâ of organisms (e.g. animals, plants, fungi, bacteria, slime mold, lichens, etc.). Discuss several of the definitions of a species as presented in class and present your own definition for a species. Compare the strengths and weaknesses of each definition. Ernst Mayr is strong proponent of the biological species concept.How does he justify his position? Do you agree or disagree? If we employ the biological species concept, when did species first exist? What were organisms before then, if not species? What might the consequences of the emergence of species be for processes of adaptation and diversification? Be sure to explain your reasoning thoroughly.

13. The process of speciation ultimately involves the development of reproductive isolation between two related populations of organisms. Describe the various types of both prezygotic and postzygotic reproductive isolation and give an example of each.

14. Respond to the following quote from the character named Mr. Spock in âStar Trekâ:âA truly successful parasite is commensal, living in amity with its host, or even giving it positive advantages, as for instance, the protozoans who live in the digestive system of your termites and digest for them the wood they eat. A parasite that regularly and inevitably kills its host cannot survive long, in the evolutionary sense, unless it multiplies with tremendous rapidity ... it is not pro-survival.âFrom what you have learned in this course, do you agree or disagree with Spock? How can you apply your reasoning to the relative âfitnessâ of HIV which causes AIDS, the Ebola virus which causes hemorrhagic fever,fleas which suck blood from dogs, or the prokaryotic ancestors of mitochondria and chloroplasts?

15. In many species of birds and mammals, clutch size is larger in populations at high latitudes than in population sat low latitudes. Species of lizards and snakes at high latitudes often have smaller clutches, however, and are more frequently viviparous (bear live young rather than laying eggs), than low-latitude species. What selective factors might be responsible for these patterns? Explain your reasoning.

16. The popular media often presents evolution as being a predictable process with a definite goal. For instance, in one âStar Trek: Voyagerâ episode, the captain instructs the shipâs computer to extrapolate the âprobable courseâ of evolution of hadrosaurs (a bipedal dinosaur), if hadrosaurs had been removed from Earth before the Cretaceous-Tertiary (K-T) Extinction and allowed to evolve on another planet. What information about the hadrosaursâ new environment would have been useful in developing the best possible prediction? Given what you know on genetic drift and selective agents, is it possible to accurately predict the long-term course of evolution?

17. Young children often develop strong food preferences that sometimes seem bizarre to their parents --- such as wanting to eat only a certain food prepared in a familiar way, or being reluctant to each new foods or foods with strong or bitter tastes (like coffee and some vegetables). Develop an evolutionary explanation for such preferences. What evidence would you gather to investigate your hypothesis and rule out alternative explanations?

18. Many organisms, such as mammals, only reproduce by sexual means. Other organisms are exclusively asexual,such as many of the bacteria and fungi. And still others have ways of propagating by both sexual and asexualmeans. Discuss the relative advantages and disadvantages of each mode of reproduction. Why arenât all organisms sexual critters? Why are many asexual organisms still very successful as evidenced by the pure abundance and diversity? What is the adaptive significance of having different genders (e.g. male and female)?In other words, why sex?

19. How might differential expression and regulation by Hox genes contribute to mosaic evolution in which different segments of an animal body plan evolve different morphology?

20. Development of a morphological structure involves many different types of gene products, including transcription factors, signaling proteins, and âeffectorâ genes such as enzymes. When a morphological change occurs in a single mutational step, which of these types might be more or less likely to be involved? Within a gene, would such single-step events be more likely to involve coding or non-coding sequences, and what characteristics of the geneâs function might affect this likelihood?

21. Since 2001, the complete DNA sequences of the genomes of many people have been determined. If humans,along with other forms of life, have evolved from a common ancestor, what evidence of this would be expected in the human genome? In what ways might the history and processes of evolution help us interpret and make sense of the human genome sequence data?

22. Paleontologists and some biologists commonly infer function, and even behavior, from anatomical details.Skeletal features, for example, are often used to infer that an extinct mammal (such as an early hominid) was highly, somewhat, or not at all arboreal. This inference assumes a good fit of form to function (i.e., optimal form). Can this assumption be justified?

23. Stephen Jay Gould (1989) and others have argued that the evolution of self-conscious, intelligent species (i.e.humans) was historically contingent: it would not have occurred had any of a great many historical events been different. The philosopher Daniel Dennett (1995) and others have disagreed, arguing that convergent evolution is so common that if humans had not evolved, some other lineage would probably have given rise to a species with similar mental abilities. What do you think, and why? If Gouldâs position is right, what are its philosophical implications, if any?

24. Explain how Intelligent Design was determined as a religious view rather than a scientific view in the court casein Dover, PA. Should a scientific explanation of evolution be included in a science curriculum in K-12 schools?How is science and religion different in how they seek answers to questions? How is term "theory" used differently in science than in everyday English use? What is biological evolution? What evidence is used to support the scientific explanation of evolution? Is it possible to accept scientific explanations without rejecting religious faith?

25. Discuss how a creationist versus an evolutionary biologist might explain some human characteristics and the implications of their differences. Sample characteristics: eyes; wisdom teeth; individually unique friction ridges(fingerprints); five digits rather than some other number; susceptibility to infections; fever when infected;variation in sexual orientation; limited life span.

Some of you will have seen Starship Troopers, a moviebased upon a novel by Robert Heinlein. The film deviates from thebook in some ways, for example the book describes a visit to aplanet to resupply the dropships used in combat operations by theM.I. (mobile infantry). Heinlein describes this visit in the book;a portion of the novel is reproduced on the followingpage.

The followig passage contains two concepts we havediscussed in class in relation to the effects of mutation onpopulations, one positive and one negative. Describe the twomutation related concepts Heinlein discusses. You must describethese concepts as a biologist - you must use the technical terms wehave used in class properly and explain the positive and negativeeffect of mutation on the evolution and health of apopulation.

(a) What is the positive effect of mutation as describedby Heinlein?

(I.E., what does Heinlein describe as a benefit ofhaving more mutations)

(b) What is the negative effect of mutation as describedby Heinlein?

(I.E., what does Heinlein describe as a problem ofhaving more mutations)

I never have learned the co-ordinates of Sanctuary,nor the name or catalogue number of the star it orbits - becausewhat you donât know, you canât spill; the location isultra-top-secret, known only to shipâs captains, piloting officers,and such ... and I understand, with each of them under orders andhypnotic compulsion to suicide if necessary to avoid capture. So Idonât want to know. With the possibility that Luna Base might betaken and Terra herself occupied, the Federation kept as much ofits beef as possible as Sanctuary, so that a disaster back homewould not necessarily mean capitulation.

But I can tell you what sort of a planet itis. Like Earth, but retarded.

Literally retarded, like a kid who takes tenyears to learn to wave bye-bye and never does manage to masterpatty cake. It is a planet as near Earth as two planets can be,same age according to the planetologists and its star is the sameage as the Sun and the same type, so say the astrophysicists. Ithas plenty of flora and fauna, the same atmosphere as Earth, nearenough, and much the same weather; it even has a good-sized moonand Earthâs exceptional tides.

With all these advantages it barely got awayfrom the starting gate. You see, itâs short on mutations; it doesnot enjoy Earths high level of natural radiation.

Its typical and most highly developed plantlife is a very primitive giant fern; its top animal life is aproto-insect which hasnât even developed colonies. I am notspeaking of transplanted Terran flora and fauna - our stuff movesin and brushes the native stuff aside.

With its evolutionary progress held down toalmost to zero by lack of radiation and a consequent mostunhealthily low mutation rate, native life forms of Sanctuary justhavenât had a decent chance to evolve and arenât fit to compete.Their gene patterns remain fixed for a relatively long time; theyarenât adaptable - like being forced to play the same bridge handover and over again, for eons, with no hope of getting a betterone.

As long as they just competed with eachother, this didnât matter too much - morons among morons, so tospeak. But when types that had evolved on a planet enjoying highradiation and fierce competition were introduced, the native stuffwas outclassed.

Now all the above is perfectly obvious fromhigh school biology ... but the high forehead from the researchstation there who was telling me about this brought up a point Iwould have never thought of.

What about the human beings who havecolonized Sanctuary?

Not transients like me, but the colonists wholive there, many of whom were born there, and whose descendantswill live there, even unto the umpteenth generation - what aboutthose descendants? It doesnât do a person any harm not to beradiated; in fact itâs a bit safer - leukemia and some types ofcancer are almost unknown there. Besides that, the economicsituation is at present all in their favor; when they plant a fieldof (Terran) wheat;, they donât even have to clear out the weeds.Terran wheat displaces anything native.

But the descendants of those colonists wonâtevolve. Not much, anyhow. This chap told me that they could improvea little through mutation from other causes, from new blood addedby immigration, and from natural selection among the gene patternsthey already own - but that is all very minor compared with theevolutionary rate on Terra and on any usual planet. So whathappens? Do they stay frozen at their present levels while the restof the human race moves on past them, until they are livingfossils, as out of place as a pithecanthropus in a spaceship?

Or will they worry about the fate of theirdescendants and dose themselves regularly with X-rays or maybe setof lots of dirty-type nuclear explosions each year to build up afallout reservoir in their atmosphere? (Accepting, of course, theimmediate dangers of radiation to themselves in order to provide aproper genetic heritage of mutation for the benefit of theirdescendants.)

This bloke predicted that they would not doanything. He claims that the human is too individualistic, tooself-centered, to worry that much about future generations. He saysthat the genetic impoverishment of distant generations through thelack of radiation is something most people are simply incapable ofworrying about. And of course it is a far-distant threat; evolutionworks so slowly, even on Terra, that the development of a newspecies is a matter of many, many thousands of years.

I donât know. Shucks, I donât know what Imyself will do more than half the time; how can I predict what acolony of strangers will do? But Iâm sure of this: Sanctuary isgoing to be fully settled, either by us or by the bugs. Or bysomebody. It is a potential utopia, and, with desirable real estateso scarce in this end of the Galaxy, it will not be left in thepossession of primitive life forms that failed to make thegrade.

ENWC201 Study Guide - Final Guide: Sympatric Speciation, Allopatric Speciation, Logistic Function

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