Topic 10 Review
Name ____________________________________________
1. What is ecology?
Ecology is the scientific study of the interactions between organisms and the environment. These
interactions determine distribution of organisms and their abundance
2. What is climate? What are the major components that make up the climate.
Four major abiotic components of climate are temperature, water, sunlight, and wind
The long-term prevailing weather conditions in an area constitute its climate
3. Compare and contrast macroclimate and microclimate.
Macroclimate consists of patterns on the global, regional, and local level
Microclimate consists of very fine patterns, such as those encountered by the community of organisms
underneath a fallen log
4. What are biomes?
Biomes are the major ecological associations that occupy broad geographic regions of land or water
Varying combinations of biotic and abiotic factors determine the nature of biomes
5. List and briefly describe the eight land biomes that your review book mentions.
Tropical Forest
•
In tropical rain forests, rainfall is relatively constant, while in tropical dry forests precipitation
is highly seasonal
•
Tropical forests are vertically layered and competition for light is intense
•
Tropical forests are home to millions of animal species, including an estimated 5–30 million still
undescribed species of insects, spiders, and other arthropods
Desert
•
Precipitation is low and highly variable, generally less than 30 cm per year; deserts may be hot or
cold
•
Desert plants are adapted for heat and desiccation tolerance, water storage, and reduced leaf
surface area
•
Common desert animals include many kinds of snakes and lizards, scorpions, ants, beetles,
migratory and resident birds, and seed-eating rodents; many are nocturnal
Savanna
•
Savanna precipitation and temperature are seasonal
•
Grasses and forbs make up most of the ground cover
•
Common inhabitants include insects and mammals such as wildebeests, zebras, lions, and hyenas
Chaparral
•
Chaparral climate is highly seasonal, with cool and rainy winters and hot dry summers
•
The chaparral is dominated by shrubs, small trees, grasses, and herbs; many plants are adapted to
fire and drought
•
Animals include amphibians, birds and other reptiles, insects, small mammals and browsing
mammals
Temperate Grassland
•
Temperate grasslands are found on many continents
•
Winters are cold and dry, while summers are wet and hot
•
The dominant plants, grasses and forbs, are adapted to droughts and fire
•
Native mammals include large grazers and small burrowers
Northern Coniferous Forest
•
The northern coniferous forest, or taiga, extends across northern North America and Eurasia
and is the largest terrestrial biome on Earth
•
Winters are cold and long while summers may be hot
•
The conical shape of conifers prevents too much snow from accumulating and breaking their
branches
•
Animals include migratory and resident birds, and large mammals
Temperate Broadleaf Forest
•
Winters are cool, while summers are hot and humid; significant precipitation falls year round as
rain and snow
•
A mature temperate broadleaf forest has vertical layers dominated by deciduous trees in the
Northern Hemisphere and evergreen eucalyptus in Australia
•
Mammals, birds, and insects make use of all vertical layers in the forest
•
In the Northern Hemisphere, many mammals hibernate in the winter
Tundra
•
Tundra covers expansive areas of the Arctic; alpine tundra exists on high mountaintops at all
latitudes
•
Winters are long and cold while summers are relatively cool; precipitation varies
•
Permafrost, a permanently frozen layer of soil, prevents water infiltration
•
Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) and
supports birds, grazers, and their predators
6. Aquatic biomes make up the largest part of the biosphere, because water covers roughly 75% of
Earth’s surface. These biomes are divided into
fresh and salt water.
7. Compare and contrast the photic zone and aphotic zone.
The upper photic zone has sufficient light for photosynthesis while the lower aphotic zone receives
little light
8. What is the benthic zone? Organic sediments also include detritus, which is dead organic matter.
The organic and inorganic sediment at the bottom of all aquatic zones is called the benthic zone
9. Compare and contrast the littoral zone and limnetic zone.
In lakes:
Water that is is too deep in the limnetic zone to support rooted aquatic plants; small drifting animals
called zooplankton graze on the phytoplankton
Rooted and floating aquatic plants live in the shallow and well-lighted littoral zone
10. Compare and contrast the oligotropic and etrophic lakes.
In Lakes:
•
Oligotrophic lakes are nutrient-poor and generally oxygen-rich
•
Eutrophic lakes are nutrient-rich and often depleted of oxygen if ice covered in winter
11. What are estuaries?
Estuaries
•
An estuary is a transition area between river and sea
•
Salinity varies with the rise and fall of the tides
•
Estuaries are nutrient rich and highly productive
•
An abundant supply of food attracts marine invertebrates and fish
12. Marine biomes include three zones and coral reefs. List and briefly describe the three zones and
coral reefs.
Intertidal Zones
•
An intertidal zone is periodically submerged and exposed by the tides
•
Intertidal organisms are challenged by variations in temperature and salinity and by the
mechanical forces of wave action
•
Many animals of rocky intertidal environments have structural adaptations that enable them to
attach to the hard substrate
Oceanic Pelagic Zone
•
The oceanic pelagic biome is a vast realm of open blue water, constantly mixed by wind-driven
oceanic currents
•
This biome covers approximately 70% of Earth’s surface
•
Phytoplankton and zooplankton are the dominant organisms in this biome; also found are freeswimming animals
Marine Benthic Zone
•
The marine benthic zone consists of the seafloor below the surface waters of the coastal, or
neritic, zone and the offshore pelagic zone
•
Organisms in the very deep benthic, or abyssal, zone are adapted to continuous cold and
extremely high water pressure
•
Unique assemblages of organisms are associated with deep-sea hydrothermal vents of volcanic
origin on mid-oceanic ridges; here the autotrophs are chemoautotrophic prokaryotes
Coral Reefs
•
Coral reefs are formed from the calcium carbonate skeletons of corals (phylum Cnidaria)
•
Corals require a solid substrate for attachment
•
Unicellular algae live within the tissues of the corals and form a mutualistic relationship that
provides the corals with organic molecules
13. The ecological study of species involves biotic ( living) and abiotic (non living) influences. Provide
examples of each.
14. What is a population?
A population is a group of individuals of a single species living in the same general area
15. What is population ecology?
Population ecology is the study of populations in relation to environment, including environmental
influences on density and distribution, age structure, and population size
16. List and briefly describe the three fundamental characteristics of the organisms in a population.
Density is the number of individuals per unit area or volume
Dispersion is the pattern of spacing among individuals within the boundaries of the population
Demography is the study of the vital statistics of a population and how they change over time
•
Death rates and birth rates are of particular interest to demographers
17. What are the three types of dispersion?
In a clumped dispersion, individuals aggregate in patches
A clumped dispersion may be influenced by resource availability and behavior
A uniform dispersion is one in which individuals are evenly distributed
•
It may be influenced by social interactions such as territoriality
In a random dispersion, the position of each individual is independent of other individuals
•
It occurs in the absence of strong attractions or repulsions
18. What is demography?
Demography is the study of the vital statistics of a population and how they change over time
•
Death rates and birth rates are of particular interest to demographers
19. What are the three types of demography (types of survivorship curves)? Provide an example of
each.
Survivorship curves can be classified into three general types:
a. Type I: low death rates during early and middle life, then an increase among older age
groups
b. Type II: the death rate is constant over the organism’s life span
c. Type III: high death rates for the young, then a slower death rate for survivors
Number of survivors (log scale)
Fig. 53-6
1,000
I
100
II
10
1
III
0
50
100
Percentage of maximum life span
20. Compare and contrast exponential and logistic growth models. What type of curves does each
have?
Exponential population growth is population increase under idealized conditions
•
Under these conditions, the rate of reproduction is at its maximum. Exponential population
growth results in a J-shaped curve. The J-shaped curve of exponential growth characterizes some
rebounding populations
•
In the logistic population growth model, the per capita rate of increase declines as carrying
capacity is reached. The logistic model of population growth produces a sigmoid (S-shaped) curve.
The growth of laboratory populations of paramecia fits an S-shaped curve
•
These organisms are grown in a constant environment lacking predators and competitors
21. What is a carrying capacity? Which growth model includes a carrying capacity?
Carrying capacity (K) is the maximum population size the environment can support. S -shaped
22. What equation is used to represent each growth model?
Logistic – rmaxN (k-N) / K
Exponential - rN
23. What is a life history?
Life history traits favored by natural selection may vary with population density and environmental
conditions. Traits that affect an organism’s schedule of reproduction and survival make up its life
history.
24. Compare and contrast K- selection and r-selection.
K-selection, or density-dependent selection, selects for life history traits that are sensitive to population
density
r-selection, or density-independent selection, selects for life history traits that maximize reproduction
25. What are density-dependent factors? Provide 4 factors that reduce birth rates or increase death
rates.
In density-dependent populations, birth rates fall and death rates rise with population density.
Competition, territoriality, disease, predation
26. What are density- independent factors? Provide an example.
In density-independent populations, birth rate and death rate do not change with population
density. Natural Disasters
27. What are age-structure pyramids? Be able to determine whether or not the population is growing
(rapidly or slowly), not growing, or declining.
One important demographic factor in present and future growth trends is a country’s age structure
Age structure is the relative number of individuals at each age. Show the relative number of individuals
of each age in a population, and can be used to predict and explain many demographic patterns.
Fig. 53-25
Rapid growth
Afghanistan
Male
Female
Slow growth
No growth
United States
Italy
Age
Male
Female Age
Male
Female
85+
85+
80–84
80–84
75–79
75–79
70–74
70–74
65–69
65–69
60–64
60–64
55–59
55–59
50–54
50–54
45–49
45–49
40–44
40–44
35–39
35–39
30–34
30–34
25–29
25–29
20–24
20–24
15–19
15–19
10–14
10–14
5–9
5–9
0–4
0–4
108 6 4 2 0 2 4 6 8 10 8 6 4 2 0 2 4 6 8
8 6 4 2 0 2 4 6 8
Percent of population
Percent of population
Percent of population
28. Be able to calculate population growth rate.
29. What is a community?
A biological community is an assemblage of populations of various species living close enough for
potential interaction
30. What are interspecific interactions? Describe the interspecific interactions that your book
mentions below.
Ecologists call relationships between species in a community interspecific interactions
Interspecific Interaction
Description
Interaction
types (+, -,
or 0)
Interspecific
•
Competition
(–/– interaction) occurs when species compete for
a resource in short supply
•
Strong competition can lead to competitive
exclusion, local elimination of a competing
species
•
The competitive exclusion principle states that
two species competing for the same limiting
resources cannot coexist in the same place
Predation
•
Predation (+/– interaction) refers to interaction
where one species, the predator, kills and eats the
other, the prey
•
Some feeding adaptations of predators are claws,
teeth, fangs, stingers, and poison
Herbivory
•
Herbivory (+/– interaction) refers to an
interaction in which an herbivore eats parts of a
plant or alga
•
SymbiosisSymbiosis is a
Parasitism
•
In parasitism (+/– interaction), one organism, the
relationship
parasite, derives nourishment from another
where two or
organism, its host, which is harmed in the process
more species live
•
Parasites that cause disease are called pathogens
in direct and
•
Parasites that live within the body of their host are
intimate contact
called endoparasites; parasites that live on the
with one
external surface of a host are ectoparasites
anothert: a larger
host and smaller
symbiont
Mutualism
•
Mutualistic symbiosis, or mutualism (+/+
interaction), is an interspecific interaction that
benefits both species
•
A mutualism can be
Obligate, where one species cannot survive
without the other
Facultative, where both species can survive
alone
Commensalism
•
In commensalism (+/0 interaction), one species
benefits and the other is apparently unaffected
•
Commensal interactions are hard to document in
nature because any close association likely affects
both species
31. What is the competitive exclusion principle?
Strong competition can lead to competitive exclusion, local elimination of a competing species
The competitive exclusion principle states that two species competing for the same limiting resources
cannot coexist in the same place
32. What is an organism’s ecological niche? Compare and contrast the fundamental niche and realized
niche.
•
•
•
•
•
•
The total of a species’ use of biotic and abiotic resources is called the species’ ecological niche
An ecological niche can also be thought of as an organism’s ecological role
Ecologically similar species can coexist in a community if there are one or more significant
differences in their niches
Resource partitioning is differentiation of ecological niches, enabling similar species to coexist in
a community
As a result of competition, a species’ fundamental niche may differ from its realized niche
33. What is cryptic coloration?
Animals also have morphological and physiological defense adaptations
Cryptic coloration, or camouflage, makes prey difficult to spot
34. What is aposematic coloration?
Animals with effective chemical defense often exhibit bright warning coloration, called aposematic
coloration
Predators are particularly cautious in dealing with prey that display such coloration
35. Compare and contrast Batesian and Mullerian mimicry.
In some cases, a prey species may gain significant protection by mimicking the appearance of another
species
In Batesian mimicry, a palatable or harmless species mimics an unpalatable or harmful model.
In Müllerian mimicry, two or more unpalatable species resemble each other
36. What is species diversity?
•
•
•
•
Species diversity of a community is the variety of organisms that make up the community
It has two components: species richness and relative abundance
Species richness is the total number of different species in the community
Relative abundance is the proportion each species represents of the total individuals in the
community
37. What are trophic levels?
Trophic structure is the feeding relationships between organisms in a community
It is a key factor in community dynamics
Food chains link trophic levels from producers to top carnivores
38. Compare and contrast food chains and food webs.
•
•
A food web is a branching food chain with complex trophic interactions
Food chains link trophic levels from producers to top carnivores
39. Compare and contrast Dominant species and Keystone species.
Dominant species are those that are most abundant or have the highest biomass
Biomass is the total mass of all individuals in a population
Dominant species exert powerful control over the occurrence and distribution of other species
Keystone species exert strong control on a community by their ecological roles, or niches
• In contrast to dominant species, they are not necessarily abundant in a community
40. What is the intermediate disturbance hypothesis?
The intermediate disturbance hypothesis suggests that moderate levels of disturbance can foster
greater diversity than either high or low levels of disturbance
• High levels of disturbance exclude many slow-growing species
• Low levels of disturbance allow dominant species to exclude less competitive species
41. What is ecological succession? Describe the two types. Provide an example of each.
Ecological succession is the sequence of community and ecosystem changes after a disturbance
Primary succession occurs where no soil exists when succession begins (volcanic island)
Secondary succession begins in an area where soil remains after a disturbance (fire)
42. Island biogeography is primarily influenced by two factors. What are they? Briefly describe them.
Species richness on islands depends on island size, distance from the mainland, immigration, and
extinction
The equilibrium model of island biogeography maintains that species richness on an ecological island
levels off at a dynamic equilibrium point
43. What is an ecosystem?
An ecosystem consists of all the organisms living in a community, as well as the abiotic factors with
which they interact
Ecosystems range from a microcosm, such as an aquarium, to a large area such as a lake or forest.
•
•
Regardless of an ecosystem’s size, its dynamics involve two main processes: energy flow and
chemical cycling
Energy flows through ecosystems while matter cycles within them
44. Compare and contrast autotrophs and heterotrophs.
•
Autotrophs build molecules themselves using photosynthesis or chemosynthesis as an energy
source; heterotrophs depend on the biosynthetic output of other organisms
45. What are the four types of heterotrophs?
Detritivores, or decomposers, are consumers that derive their energy from detritus, nonliving organic
matter
Omnivore
Carnivore
Herbivore
46. What is an eutrophic lake?
•
•
•
The addition of large amounts of nutrients to lakes has a wide range of ecological impacts
In some areas, sewage runoff has caused eutrophication of lakes, which can lead to loss of most
fish species
Eutrophication occurs when cyanobacteria and algae grow rapidly in response to added
nutrients, ultimately reducing the oxygen concentration and clarity of the water
47. What is an evapotranspiration?
In terrestrial ecosystems, temperature and moisture affect primary production on a large scale
Actual evapotranspiration can represent the contrast between wet and dry climates
Actual evapotranspiration is the water annually transpired by plants and evaporated from a landscape
It is related to net primary production
48. How much energy is transferred between trophic levels? 10%
Trophic efficiency is the percentage of production transferred from one trophic level to the next
It usually ranges from 5% to 20%
Trophic efficiency is multiplied over the length of a food chain
49. What are biogeochemical cycles?
•
Nutrient circuits in ecosystems involve biotic and abiotic components and are often called
biogeochemical cycles
50. Briefly describe the carbon cycle.
The Carbon Cycle
• Carbon-based organic molecules are essential to all organisms
• Carbon reservoirs include fossil fuels, soils and sediments, solutes in oceans, plant and animal
biomass, and the atmosphere
• CO2 is taken up and released through photosynthesis and respiration; additionally, volcanoes and
the burning of fossil fuels contribute CO2 to the atmosphere
51. Briefly describe the nitrogen cycle. (Include nitrification and denitrification in your explanation)
The Terrestrial Nitrogen Cycle
• Nitrogen is a component of amino acids, proteins, and nucleic acids
• The main reservoir of nitrogen is the atmosphere (N2), though this nitrogen must be converted to
NH4+ or NO3– for uptake by plants, via nitrogen fixation by bacteria
• Organic nitrogen is decomposed to NH4+ by ammonification, and NH4+ is decomposed to NO3– by
nitrification
• Denitrification converts NO3– back to N2
52. Compare and contrast bioremediation and bioaugmentation.
Bioremediation is the use of living organisms to detoxify ecosystems
The organisms most often used are prokaryotes, fungi, or plants
These organisms can take up, and sometimes metabolize, toxic molecules
Biological augmentation uses organisms to add essential materials to a degraded ecosystem
• For example, nitrogen-fixing plants can increase the available nitrogen in soil
53. What is biodiversity?
Biodiversity has three main components:
a. Genetic diversity
b. Species diversity
c. Ecosystem diversity
54. What is acid precipitation, biological magnification, and greenhouse effect? How are human
actions effecting these terms?
Acid Rain - Defined as rain, snow, or fog with a pH less than 5.2. The burning of wood and fossil fues
releases sulfur oxides and nitrogen oxides into the atmosphere. These oxides react with water, forming
sulfuric acid and nitric acid
Biological Magnification – toxins become more concentrated in successive trophic levels of a food web.
The toxins cannot be broken down biologically by normal chemical means, so they magnify in
concentration as they move through the food chain.
Greenhouse effect – refers to the absorption of heat the Earth experiences due to certain atmospheric
gases. Carbon dioxide and water vapor intercept and absorb much reflected infrared radiation, rereflecting some back toward Earth.
Because of the burning of fossil fuels, CO2 levels have been steadily increasing. One effect of this
increases is that Earth is being warmed significantly (global warming)
55. How is the greenhouse effect related to global warming?
Because of the burning of fossil fuels, CO2 levels have been steadily increasing. One effect of this
increases is that Earth is being warmed significantly (global warming)