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UA / Biological Sciences / BSC 108 / What are the two models of the pace of speciation?

What are the two models of the pace of speciation?

What are the two models of the pace of speciation?


School: University of Alabama - Tuscaloosa
Department: Biological Sciences
Course: Intro Biology Non Major I
Professor: Yates
Term: Fall 2016
Tags: Biology
Cost: 50
Name: BSC 108 Final Exam Study Guide
Description: These notes have chapter reviews and key terms, along with all the questions Professor Yates suggested we study.
Uploaded: 12/05/2016
11 Pages 166 Views 9 Unlocks

BSC 108- Final Exam Review (Chapters 13,14, 18-20) Wednesday, November 30, 2016 4:53 PM

What are the two models of the pace of speciation?

Chapter 13- How Populations Evolve 

Key ideas and terms:

▪ Evolution= Change over time

▪ Natural Selection= Mechanisms for the change

Which barriers prevent mating or fertilization between species?

If you want to learn more check out Why did we have a civil war?
We also discuss several other topics like What tables are to be interrogated by the search?

Chapter 14- How Biological Diversity Evolves 

Key ideas and terms:

Speciation- the gene pools of two or more populations must be separated from each other and in  turn can create new species.

▪ Changes in organisms leading to new species can be rapid

Species have prezygotic and postzygotic mechanisms to isolate their gene pools from the gene  pools of other species.

What are examples of abiotic factors?

If you want to learn more check out What are the different levels of nurses?

▪ Changes that can lead to speciation can involve development and exaptation 

Chapter 18- Ecology and the Biosphere 

Key ideas and terms:

▪ Ecology-The scientific study of the interactions of organisms and their environments  

Biome- A major terrestrial or aquatic life zone, characterized by vegetation type in terrestrial  biomes or the physical environment in aquatic biomes

□ Aquatic biomes occupy ~75% of Earth's surface

Chapter 19- Population Ecology Don't forget about the age old question of What does the "intern's syndrome" express?
Don't forget about the age old question of Can governor choose his cabinet members?

Key ideas and terms:

▪ The growth rate- The change in population size per time interval ▪ Population- group of individuals of a single species that occupy a defined area Chapter 20- Communities and Ecology 

Key ideas and terms:

The marked increase in atmospheric CO2 could cause an increase in global temperatures, with  potentially disastrous consequences  Don't forget about the age old question of Is every circuit free?

▪ Primary cause of loss of biodiversity is lost with habitat destruction (primarily by humans) 1. What is microevolution?

a. Changes in allele frequencies within populations

i. Often associated with adaptation

ii. Can be measured from one generation to the next

iii. Ex: changes in frequency of color alleles of some animals maybe to blend in

 BSC 108 Page 1

iii. Ex: changes in frequency of color alleles of some animals maybe to blend in 2. What is macroevolution?

a. Major changes in the history of life

i. Origin of new species

ii. Generates biological diversity

iii. Ex: changes in plants that led to mosses, conifers and flowering plants 3. What is a species?


Groups of organisms whose members have the potential to interbreed with one another in nature to  produce fertile offspring, reproductively isolated from other such groups.

4. What is allopatric speciation?

a. When species evolve in geographic isolation


Usually involves a geographic barrier, preventing members of two populations from mating with  one another.

ii. Ex of barriers: deep canyons, mountains, and/or oceans.

5. What is sympatric speciation?

a. When species evolve without geographical isolation

i. Probably associated with a genetic barrier due to a single mutational event

ii. Important in plants, but not widespread among animals

iii. Requires a subdivision of the gene pool of a single population

6. What special circumstances are required to keep the gene pools separated in sympatric speciation? a. Segregation of habitat

b. Major alterations in mate recognition or behavior

c. Genetic incompatibility  

7. Know the two models of the Pace of Speciation.

a. Gradualism 

i. Mechanism envisioned by Darwin  


Slow and Steady accumulation of small changes leads to production of species over vast stretches  of time


Leads to the prediction that the fossil record should show numerous forms in a continuous series of  change from ancestral to descendant species

b. Punctuated Equilibrium  

i. Mechanism proposed by Eldredge and Gould

ii. Species diverge in spurts of rapid change, followed by long periods of stasis


Leads to the prediction that the fossil record should show the most drastic changes in appearance at  the time that new species branch from parent species  

c. Evolution incorporates both gradual and punctuated episodes 8. What are prezygotic barriers? Know the 5 types.

a. Barriers that prevent mating or fertilization between species. i. Temporal isolation  

1) Mating at different times (of the day, season, etc..)

2) Ex: Eastern and Western spotted skunk

ii. Habitat isolation 

1) Garter snakes occupy the same area but live in different habitats iii. Behavioral isolation  


Blue footed boobies and many other animals display complex courtship in order to attract  mates. Other species cannot mimic these, therefore they do not mate with other species.  

iv. Mechanical isolation  


Snails of different species may attempt to mate, but differences in shell shape prevent them  from mating  

v. Gametic isolation 


Sperm and Egg of two sea urchins are released, but the proteins on the surface of the eggs and  sperm cannot bind to each other, so no offspring is produced.

9. What are postzygotic barriers? Know the 3 types.

a. Barriers that prevent survival and/or reproduction of the hybrid offspring i. Hybrid inviability 

1) Offspring fail to complete development  

2) Ex: Different salamander species

ii. Hybrid Sterility  

1) Different species may mate, and produce viable offspring, but they are sterile 2) Ex: Horse and donkey make a mule.

iii. Hybrid Breakdown 


The first generation of hybrids may be both viable and fertile, but the offspring of these  hybrids are weak, feeble, or sterile

2) Ex: domesticated rice strains

10. What is ecology?

 BSC 108 Page 2

10. What is ecology?

a. The scientific study of the interactions of organisms and their environments  11. What are abiotic factors? Know the 5 examples.

a. The nonliving chemical and physical factors in an environment

i. Energy Source 

1) Solar energy powers almost all ecosystems

ii. Environmental Temperatures 

1) Huge effect on metabolism

iii. Water 

iv. Wind 

1) Some organisms rely on nutrients being blown to them by the wind v. Rocks and Soil 

1) Composition of soil can affect water chemistry  

12. What are biotic factors? Know some examples.

a. Producers or Autotrophs 

i. Plants

b. Consumers or heterotrophs 

i. Animals

c. Decomposers or Detritivores  

i. Vultures

13. What are the four levels of ecology? Know what each is concerned with. a. Ecology can be divided into four increasingly comprehensive levels: i. Organismal ecology


Concerned with evolutionary adaptations that enable individual organisms to meet the  challenges posed by their abiotic environments

ii. Population ecology

1) Concerned with populations, groups of individuals of the same species living in the same area 2) Concentrates mainly on factors that affect density and growth

iii. Community ecology

1) Communities- assemblages of populations of different species

2) Focuses on how interactions between species affect community structure organization iv. Ecosystem ecology


Ecosystem- include all the abiotic factors in addition to the community of species in a certain  area


Focuses on energy flow and the cycling of chemicals among the various abiotic and biotic  factors

v. The Biosphere is the global ecosystem

14. What is a habitat?  

a. Specific environments where organisms live

i. Reveal patchiness on an even smaller scale  

15. What are 3 types of adaptations that enable organisms to adjust to changes in their environment? a. Physiological

i. Thermoregulation: responses by organisms occur quickly

ii. Acclimation: physiological response that is long term  


The ability to acclimate is related to the range of environmental conditions a species naturally  experiences

iii. Among vertebrates


Birds and mammals can tolerate the greatest temperature extremes because they are  endotherms (warm blooded)


Reptiles are more limited in the climates they can tolerate because they are ectotherms (Cold  blooded)  

b. Anatomical responses


Many organisms respond to environmental challenge with some type of change in body shape or  anatomy  

c. Behavioral Responses  


In contrast to plants, most animals can respond to an unfavorable change in the environment by  moving to a new location

ii. Humans exhibit an especially rich range of behavioral responses  

16. Name 2 types of Aquatic Biomes? What is the salinity of each?

a. Freshwater biomes 

i. Lakes, streams, rivers, and wetlands

ii. Salinity= less than 1%

b. Marine biomes 

i. Oceans, intertidal zones, coral reefs, and estuaries

ii. Salinity= around 3%

 BSC 108 Page 3

ii. Salinity= around 3%

17. What are some uses for freshwater?

a. Drinking water, crop irrigation, sanitation and industry.

18. What are the 2 categories of freshwater? Know examples of each. a. Standing water 

i. Lakes and ponds

b. Flowing water 

i. Rivers and streams

19. What are wetlands?

a. Transitional biome between an aquatic ecosystem and a terrestrial one  b. Among the richest of biomes in species diversity

20. What are estuaries?

a. Areas where a freshwater stream or river merges with the ocean b. One of the most biologically productive environments on Earth 21. How are terrestrial biomes determined? Know the examples from class. a. Climate (primarily temperature and rainfall) and vegetation type 22. What is the tree line?

a. The elevation at which trees can no longer grow

b. Around 10,000 feet in most of the western United States

23. Know the water cycle.

24. What is population density?

a. The number of individuals of a species per unit of area or volume  25. What is the mark-and-recapture technique and why is it utilized? a. It is a technique to estimate an animals population size.


It is the process of capturing a portion of the population, marking them, then releasing them. Later,  another portion is captured and the number of marked individuals is noted.  

c. One would be able to estimate the whole population using simple proportions, based on this technique. 26. What are the 2 growth models? Know what each one looks like on a graph.

a. Exponential growth model (The ideal of an unlimited environment)

i. Describes the rate of expansion of a population under ideal, unregulated conditions  


The rate at which a population grows depends on the number of individuals already in the  population

b. Logistic growth model (The reality of a limited environment)

i. A population may grow exponentially for a while, but eventually one or more environmental   BSC 108 Page 4


A population may grow exponentially for a while, but eventually one or more environmental  factors will limits its growth

ii. Describes the growth of an idealized population that is slowed my limiting factors

27. What is carrying capacity?


The number of individuals in a population that the environment can just maintain with no net increase or  decrease.

28. How does the US Endangered Species Act define an endangered species vs a threatened species?


Endangered Species- one that is "in danger of extinction throughout all or a significant portion of its  range"

b. Threatened Species- one likely to become endangered in the foreseeable future.?


Community- Assemblages of populations of different species living close enough for potential  interactions

29. What is an ecological niche?

a. The sum total of a species' use of the biotic and abiotic resources in its environment b. The species' ecological role

30. What did G. F. Gause study? What model organism did he utilize?  

a. He studied the effects of interspecific competition in two closely related species of protists.  b. He studied the Paramecium aurelia and the Paramecium caudatum  

31. What were his results?  


He concluded that two species so similar that they compete for the same limiting resources cannot  coexist in the same place.

b. This concept is called the competitive exclusion principle  

32. What does the competitive exclusion principle state? ^^^

33. Know the difference between predator and prey.

a. Predators

i. Have adaptations such as claws, teeth, poison to help catch and subdue prey ii. Are fast and agile

iii. Most predators have acute senses

b. Prey

i. Passive defenses such as hiding

ii. Active defenses such as escaping

iii. Mechanical defenses such as hard shells or quills

iv. Behavioral defenses include alarm calls and mobbing


Distraction displays directs the attention of the predator away from a vulnerable prey to a prey that  is more likely to escape  

vi. Camouflage or cryptic coloration

vii. Chemical defenses such as warning coloration (bright colors of snakes and frogs) viii. Mimicry  

34. What are some of the plant defenses against herbivores?

a. Spines and thorns

b. Chemical toxins


Morphine, strychnine, and nicotine may be harmful to humans. Other chemicals are utilized by  humans such as cinnamon and peppermint.  

35. What are some of the animal defenses against predators?

a. Passive defenses  

i. Hiding (Camouflage or cryptic coloration)

ii. Mimicry

b. Active defenses  

i. Escaping  

ii. Alarm calls

iii. Mobbing

iv. Distracting displays

 BSC 108 Page 5

iv. Distracting displays

c. Mechanical defenses  

i. Hard shells or quills  

36. Why do organisms enter into symbiotic relationships?

a. When two organisms coexist closely in a long term relationship

37. What types of symbiotic relationships are there?

a. Mutualism- both organisms benefit

b. Commensalism- One organism benefits, while the other one is neither helped nor hurt c. Parasitism- One organism benefits (parasite), while the other is harmed (host) 38. What is a trophic level?

a. Divides species in a community based on their main sources of nutrition 39. Know the different trophic levels and examples of organisms that belong in each. a. Producers- (autotrophs)  

i. Typically plants and algae that use photosynthesis  

ii. Producers because they make their own food

b. Primary Consumers- (Herbivores)

i. Herbivores eat plants and are called primary consumers

c. Secondary Consumers- (Carnivores)

i. Carnivores which eat herbivores are called secondary consumers

d. Tertiary Consumers- (Carnivores)

i. Carnivores which eat other carnivores are called tertiary consumers

e. Quaternary Consumers- (Carnivores)

i. They basically eat everything and have no predators

40. What are the 4 main nutrients that cycle? Be able to label the cycles on a chart. a. The Carbon Cycle 


Photosynthesis by plants and cellular respiration by both plants and animals, then decomposition  and burning of fossil fuels.

b. The Phosphorous Cycle 


Phosphate ions deposited in sediments over the course of millions of years are brought to Earth's  surface by the upheaval of Earth's crust and the formation of new mountain ranges. The phosphate  in sedimentary rocks are mined by humans and weathered by forces of nature but never enters the  atmosphere.

 BSC 108 Page 6

c. The Nitrogen Cycle 

i. Carried out by certain bacteria in the root modules of plants.

d. The Water Cycle 

i. Atmosphere, oceans, and land

41. What is biological magnification?

a. A process in which toxins become more concentrated in successive trophic levels of a food web 42. What is an energy pyramid?


Energy flows as organic matter through the trophic levels of an ecosystem and much of it is lost at each  link in the food chain.

b. Only about 10% of energy is passed to the next trophic level

 BSC 108 Page 7

43. Why are introduced species bad?

a. Introduced species can take over environments rapidly and cause rapid extinctions. 44. How are humans impacting ecosystems?

a. We are destroying ecosystems at a fast rate by:

i. Habitat destruction  

ii. Overexploitation  

iii. Introducing different species

45. Why is biodiversity important?

a. Biodiversity paves ways to many things we, as humans, rely on:

i. Food, clothing, shelter

ii. Oxygen, soil fertility, and medicinal substances

b. The loss of genetic diversity can lead to decrease resistance to disease and illness


Loss of species diversity can upset the balance of food webs, loss of medicine and other future  discoveries  

46. What is a food web? Be able to read one.

a. The feeding relationships in an ecosystem; not as simple as a simple food chain.

47. What factors increase the loss of biodiversity?

a. #1, Habitat destruction.

b. Invasive species

c. Overexploitation

48. What is sustainable development?

a. The balancing of human needs with the health of the biosphere


The goal of it is to establish long-term prosperity of human societies and the ecosystems that support  them

49. What is species richness? What is relative abundance?

a. Species richness- the total number of different species in the community

b. Relative abundance- refers to how common or rare a species is compared to other species in the area 50. What was the name of the publication that Darwin published? In what year was it published?  a. On the Origin of Species by means of Natural Selection

 BSC 108 Page 8

a. On the Origin of Species by means of Natural Selection

b. November 24, 1859

51. What are the two main points of Darwin’s publication?

a. Challenged the notion that the Earth was relatively young

b. And populated by unrelated species  

52. What is the basic idea of natural selection?

a. Organisms can change over generations

b. Individuals with certain heritable traits leave more offspring than others

53. What is the result of natural selection?

a. Evolutionary adaptation

54. Darwin based his theory of natural selection on two key observations. What are the two observations? a. Overproduction

i. All species tend to produce excessive numbers

ii. This leads to a struggle for existence

b. Individual variation

i. Variation exists among individuals in a population  

ii. Much of this variation is heritable  

55. What is unequal reproductive success?

a. The result of overproduction and individual variation (Natural selection)

b. Those individuals with traits best suited for the local environment leave more fertile offspring 56. What are homologous structures? Know examples we talked about.

a. Similarities in structures in different animals due to common ancestry  

i. Human and cat

57. What is biogeography?

a. The study of the geographic distribution of species

b. First suggested to Darwin that today's organisms evolved from ancestral forms.

58. What is comparative anatomy?

59. What is comparative embryology?

a. Comparisons of body structure between different species  

b. Compares that evolution is a remodeling process  

60. What is a fossil? How are fossils formed?

a. Preserved remnants or impressions left by organisms that lived in the past

i. Often found in sedimentary rocks

61. Where are fossils found?

a. Sedimentary rocks

62. What type of scientist studies fossils?

a. Paleontologists  

63. Name 3 examples of natural selection in action.

a. Pesticide resistance in insects

b. The development of antibiotic-resistant bacteria.  

c. Drug-resistant strains of HIV

64. What is a mutation?  

a. Changes in the DNA of an organism  

65. What is sexual recombination?

a. The process of shuffling alleles during meiosis  


What is directional selection? What does the phenotypic graph look like compared to the original  population curve?

a. Directional Selection

i. Shifts the phenotypic curve of a population

ii. Selects in favor of some extreme phenotype  

 BSC 108 Page 9


What is disruptive selection? What does the phenotypic graph look like compared to the original  population curve?

a. Disruptive selection (See above graph)

i. Can lead to a balance between two or more contrasting morphs in a population 68.

What is stabilizing selection? What does the phenotypic graph look like compared to the original  population curve?

a. Stabilizing selection (See above graph)

i. Maintains variation for a particular trait within a narrow range

69. Sickle-cell anemia confers resistance to what disease?

a. Malaria

70. What is a habitat?

a. See #14

71. What is a geographic range?

a. The geographic area a species can be found

72. What are some factors that limit biotic potential?

a. Disease, predation, and restricted food resources

73. What factors that have increased the biotic potential for humans. a. Size of the litter (offspring, # of kids)

b. Sufficient food supply

c. Technology, industrialization

d. Medicine

e. Cleanliness

f. Hygiene  

74. Which way does energy flow through ecosystems?

a. From producers to consumers

i. Light energy to heat energy

75. What is a biological pyramid?

a. Same as the energy pyramid

b. Designed to show the bio productivity at each trophic level in an ecosystem 76. How much energy is available to the next level in a biological pyramid? a. Around 10% 

77. How much sunlight energy is captured by producers?

a. Around 10%

78. What is eutrophication?


Excessive richness of nutrients in a lake or body of water, frequently due to runoff from the land, which  causes a dense growth of plant life and death of animal life due to lack of oxygen.

79. What are some things we can do to move toward a sustainable future?  a. Reduce consumption 

i. Buy less

ii. Avoid excess packaging

iii. Fix things rather than discarding them

b. Be more energy efficient  

i. Bike, walk, car pool, or take public transportation

ii. Purchase efficient appliances and vehicles

c. Promote recycling  

i. Recycle at home and work

ii. Purchase products made from recycled material

d. Take political action 

 BSC 108 Page 10

ii. Purchase efficient appliances and vehicles

c. Promote recycling  

i. Recycle at home and work

ii. Purchase products made from recycled material

d. Take political action 

i. Vote for pro-environment policymakers

ii. Join an environmental advocacy group

iii. Write letters in support of environmental causes  

e. Promote research and education 

i. Serve as a role model through your actions

ii. Sponsor environmental initiatives on your campus and workplace iii. Talk about environmental issues with family and friends f. Think long-term 


Realize that addressing environmental problems sometimes come with short-term costs, but long term benefits

ii. Support policymakers and businesses that promote long-term environmental thinking.  BSC 108 Page 11

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