Bio2 Exam3 Book Notes Chapter 54

What is responsible for seasonal changes in climate?

The tilt of Earth's axis, coupled with Earth's orbit around the sun. Higher latitudes experience greater seasonal variation than lower latitudes do. Around the equator, day length and seasonal temperatures change only slightly over the course of the year, although there are seasonal shifts in precipitation patterns.

What are estuaries?

These form where rivers meet the sea, creating variability in salinity, sediment, and light conditions.

How can vegetation influence Earth's climate?

These organisms can "engineer" the environment in multiple ways. This, especially forests, can have large effects on temperature and precipitation at local and even regional scales. (ex: measurements of energy exchange in tropical forests that have been converted to pastureland show that forests make the climate cooler and moister. While forests absorb heat by reflecting less sunlight and decrease convective heat loss by acting as a wind screen, this is more than balanced by the cooling effect produced by evapotranspiration

How are the circulation patterns of ocean currents generated?

They are driven by prevailing winds, which move water by means of frictional drag.

What is a metapopulation?

this is a group of geographically isolated populations linked together by dispersal. For example, a cluster of meadows might be considered this if Clematis seeds from one meadow had the potential to disperse to another meadow.

What is alpha diversity?

this is another name for the local scale of spacial scales, and it typically encompasses a single community

Why would we call a species endemic?

because they occur in one particular location and nowhere else on Earth. Thus, for example, Clematis can be said to be this to the central United States because its geographic range is restricted to that region.

How do ocean currents have a tremendous effect on Earth's climate?

because they transport heat

What are landscapes?

these are geographic areas that include multiple ecosystems (sometimes referred to as meta-ecosystems)

What are the three main factors that can modify the pattern of global climate, determining regional and local variation in climate and other aspects of the physical environment?

1) Earth's topography 2) Vegetation 3) The effects of humans

Ecologists recognize what 3 basic dispersion patterns?

1) Regular (or uniform) dispersion, characterized by evenly spaced individuals 2) Random dispersion, in which individuals are randomly spaced 3) Clumped dispersion, in which individuals tend to be clustered in groups

The actual number of species on an island will ultimately depend on what 2 factors?

1) the size (area) of the island. The smaller the island, the fewer resources it provides, the greater the potential for competition, and the higher the extinction rate will be. 2) the distance of the island from the species pool. The father the island is from the source of immigrants, the lower the immigration rate will be.

What is the regional species pool? (aka gamma diversity)

All the species that are limited to a region are part of this.

The birth rate can be calculated with what equation?

B = bN0 where B is the product of the per capita birth rate (b) and N0 is the population size at time 0.

Why use plants as a way of classifying biomes?

Because plants are immobile, they must adapt to environmental conditions in order to be successful over long periods of time. Thus the growth forms of plants strongly reflect their environment in ways that can be compared around the world. Furthermore, by providing three-dimensional structure, by modifying physical conditions near the ground, and by providing food, dominant plants strongly influence the organisms living there.

What are greenhouse gases?

Carbon dioxide, methane, nitrous oxide, water vapor, and certain other gases in the atmosphere are known are these because they allow sunlight into Earth's atmosphere but trap heat radiating back out toward space

What is the mark-recapture method to count individuals in a population?

Counting mobile organisms is more difficult because individuals move into and out of sampling areas. In such cases, investigators may use this method. They begin by capturing, marking, and then releasing a number of individuals. Later, after the marked individuals have had time to mix with unmarked individuals in the population (but before enough time has elapsed for births, deaths, and individual movement to affect the population size significantly), another sample of individuals is captured. This sample is then used to obtain an estimate of the total size of the population in the sampling area.

The death rate can be calculated with what equation?

D = dN0 where D is the product of the per capita death rate (d) and N0 is the population size at time 0.

What is Earth's rotation responsible for?

Earth's rotation, which moves east to west, is responsible for generating global wind and ocean currents. Because Earth is a sphere, the velocity of its rotation around its axis is fastest at the equator, where its diameter is greatest, and is slowest close to the poles.

How did Wallace establish the conceptual foundations of biogeography?

He detailed the factors known at the time that influence the distributions of animals, including past glaciation, land bridges, deep ocean channels, and mountain ranges.

What did Thomas Lovejoy and his colleagues find while conducting the Biological Dynamics of Forest Fragments Project (the largest experiment on Earth)?

He was able to survey the species diversity in different-sized fragments in Brazil that were surrounded by deforested land. His group found that after more than 30 years of isolation, even the largest defrosted fragments surveyed had lost half of their bird species diversity. They also found that even minimal distances of 80 meters between fragments resulted in strong avoidance of the clearings, and thus isolation, by birds, insects, and tree-dwelling mammals that lived in the fragments. They also found that the fragmentation exposed species within a fragment to a variety of potential hazards, including extreme heat, fires, hunting, predators, diseases, and invasive species.

How does dispersal come in many forms?

It can be active when movement is controlled by the individual, such as you might see with elephants; passive when movement is controlled by the physical environment, as in corals and dandelions; or facilitated by active agents, such as birds or bats dispersing seed-laden fruits

What is a transect?

Individuals of a population may be counted along this, which is a line drawn across an area within the range of the population (often designated by a tape measure marked at regular intervals).

What are some important factors in controlling population dynamics?

Intraspecific competition (competition for shared resources by individuals of the same species) and interspecific interactions (interactions among individuals of different species such as competition, predation, and positive interactions) and dispersal

Besides controlling temperature, what else does solar energy input also determine?

It also determines atmospheric circulation and associated precipitation patterns. Air in the region surrounding the equator receives the greatest input of solar energy

What is demography?

Measuring how a population changes over time requires following this- which is its births, deaths, immigration, and emigration.

What is the equation that represents the relationship of the number of individuals added to increase a population and the number of individuals lost from the population that decrease it?

Nt = N0 + (B-D) + (I-E) where Nt = the population size at time t, N0 = the population size at time 0, B = the number of individuals born between time 0 and time t, D = the number that died between time 0 and time t, I = the number that immigrated between time 0 and time t, and E = the number that emigrated between time 0 and time t. This equation can be used to get a population growth rate

What are gyres?

Patterns of water movement set up these rotating circulation patterns which rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere

What is the population density?

Populations are often too large and too mobile for a full census; often the extent of the range of a population is not perfectly known. In these cases, ecologists instead determine this, which is the number of individuals within a given area (or volume, for organisms living in water), and then extrapolate from these samples to estimate the total population size.

What is the species-area relationship?

Relationship in which species diversity increases with increasing area. The relationship has most often been measured for islands or island like habitats- any isolated area surrounded by a "sea" of dissimilar habitat.

How have humans affected the environment?

Structures such as dams, bridges, and nuclear power plants can dramatically transform rivers and lakes. Urban areas also modify the surrounding climate because concrete, asphalt, and even the darker roofs of buildings absorb heat from solar radiation and radiate that heat in the evening hours. Cities also produce more heat through the burning of fossil fuels from cars, factories, and buildings.

How can biogeographers determine the role of each process, vicariance and dispersal, when reconstructing the evolutionary history of a particular species?

Taxonomists have developed powerful molecular methods of reconstructing the phylogenetic relationships among organisms that can be used to understand how organisms came to occupy their present-day distributions. Phylogenetic trees can be used to discover whether the distribution of an ancestral species was influenced by a vicariant event, such as continental drift or a change in sea level, or is simply the result of a dispersal event.

What are the effects of when forests are cut and replaced by vegetation such as grasses?

The albedo effect and convective heat loss intensify while evapotranspiration decreases, causing overall air temperatures to rise and precipitation to decrease, creating more arid conditions.

How does the Earth's atmosphere contribute to global climate patterns?

The atmosphere moderates Earth's surface temperatures by trapping heat energy

What are biogeographic regions?

The biotas of different parts of the world differ enough to allow us to divide Earth into these many continental-scale areas, each containing characteristic assemblages of species. The boundaries of these were originally proposed by Wallace, and represent assemblages of species that change dramatically, often over short distances. A major process controlling the formation of these biogeographic regions is continental drift.

What is beta diversity?

The change in the number of species from one community to another across the landscape is known as this

What is an example of a classic type of biome that may be widely separated, occurring on different continents, depending in large part of the presence of suitable climate conditions?

The desert biome occurs in such distant locations as Arizona in the North American Southwest and the Namib Desert in Africa; both locations are extremely dry and dominated by succulent plants such as cacti and by drought-tolerant shrubs and grasses.

What are the processes that create global climate patterns?

The energy that drives global climate patterns ultimately originates from the sun.

What are prevailing winds?

The interaction of Earth's rotation and north-south air mass movement sets up a pattern of circulating surface air referred to as these, which blow from east to west in the tropics (the trade winds); from west to east in mid-latitudes (the westerlies); and from east to west again above 60 degrees north or 60 degrees south latitude (the easterlies)

What is the intertidal zone?

The portion of the benthic coastal zone lying between the high and low tide levels is this zone, where tidal movements create conditions of highly variable light and temperature, alternately exposing organisms to air and water. These zones can occur on the open coast as sandy or rocky beaches, or in more protected bays as estuaries.

What are biomes?

They are groupings of ecologically similar organisms shaped by the environment in which they are found. The classification of these is most often and easily applied to terrestrial systems. Ecologists classify them principally by the growth forms of their dominant plants, which reflect the evolution of those plants under annual patterns of temperature and precipitation. The same classic types of these may be widely separated, occurring on different continents, depending in large part on the presence of suitable climate conditions.

Extrinsic factors such as predators can provide what for populations?

They can provide checks on populations, thereby limiting outbreaks, or on the other end, local extinctions.

What are the effects of fragmentation edge-effects?

They not only reduce the immigration rate from one fragment to another, thus contributing to a smaller species pool, but they effectively reduce the size of fragment, thus increasing the extinction rate, by making the edge of the fragment much less hospitable habitat.

Species that show wide fluctuations in population size tend to have what kind of reproductive strategies?

They tend to have reproductive strategies that allow them to respond rapidly to changing resources. They may also have predators that are able to take advantage of these outbursts in growth.

Because of the dominant role that humans play in almost every ecological system on Earth, a "use-inspired" motivation often shapes ecologists' research and teaching. What does that mean?

They understand that scientific knowledge of ecology greatly improves our ability to grow food for ourselves reliably and sustainably, to manage pests and diseases safely and effectively, and to deal with natural disasters such as floods and fires. The greater our understanding of ecological connections, the more likely it is that we can accomplish these things without causing a cascade of unanticipated consequences for ourselves and the other life on Earth.

What are important things to know about the boreal forest biome?

This biome is also known as the taiga. Winters are long and very cold: summers are short, although relatively warm. These forests of the Northern Hemisphere are dominated by coniferous trees. The dominant mammals, such as moose and hares, eat leaves, but the seeds in conifer cones support a variety of rodents, birds, and insects. Many small mammals hibernate in winter, but some remain active under the snowpack, serving as food for predators.

What are important things to know about the desert biome?

This biome is concentrated in two belts, where warm, dry air sinks under high atmospheric pressure. The driest of these regions, where rains rarely fall, are far from the oceans, as in the center of Australia and the middle of the Sahara in Africa. Small animals are inactive during the hottest part of the day, remaining in underground burrows. Mammals have physiological adaptations for conserving water, including a reduced number of sweat glands and kidneys that produce highly concentrated urine. Many animals require no water beyond what they can extract from the carbs in their food. Humans have used this area for livestock grazing and agriculture for centuries.

What are important things to know about the tundra?

This biome is found at high latitudes characterized by low temps and a short growing season. It is underlain by permafrost. The soil is wet because water can't drain through the permafrost, so trees can't grow because their roots can't penetrate the permafrost. Instead, it is characterized by sedges, forms, grasses, and low-growing shrubs. Lichens and mosses are also important vegetation. These plants are several structural and physiological adaptations that help them to conserve heat. Most animals are either summer migrants or are dominant for much of the year. Resident birds and mammals have thick fur or feathers that may change color with the seasons, from brown in the summer to white in the winter.

What are important things to know about the temperate deciduous forest biome?

This biome is found in eastern North America, Eastern Asia, and Europe. Temperatures fluctuate dramatically between summer and winter, although precipitation is fairly evenly distributed throughout the year. The trees that dominate these forests lose their leaves during the cold winters and produce new leaves during the warm, moist summers. Many plant genera are shared among the 3 regions where this biome is found. Some animals (including many birds) migrate to find food and escape the winter cold. Others hibernate, often in underground burrows. Many insects go into a state of diapause (suspended development)

What are important things to know about the tropical rainforest biome?

This biome is found in equatorial regions where rainfall and temperatures are high year round. With no season unsuitable for growth, it is the most productive and species-rich of all biomes. They provide humans with a range of products, including fruits, nuts, medicines, fuels, pulp, and furniture wood.

What are important things to know about the temperate grassland biome?

This biome is found in many parts of the world, all of which are relatively dry for much of the year. Most have hot summers and relatively cold winters. These plants support herds of large grazing mammals and are adapted to grazing and to fire. There are few trees. The topsoil is usually rich and deep, so most of it has been turned over to agriculture and no longer exists in its natural state.

What are important things to know about the temperate evergreen forest?

This biome occurs along the coast of continents in both hemispheres at middle to high latitudes, where winters are mild and wet and summers are cool and dry. In the Northern Hemisphere, the dominant trees are conifers, some of which are the world's most massive tree species. In the Southern Hemisphere, the dominant trees are southern beeches, some of which are evergreen.

What is the Walter climate diagram?

This graphic technique plots temperature and precipitation data in a simple way that visualizes a "growing season"- those months when average temperatures are above freezing and when average precipitation is sufficient for plant growth. These are predicted on the "rule of thumb" that plant growth requires temperatures above 0 degrees Celsius and at least 2mm of precipitation for each 1 degree Celsius rise in temperature above 0. They have two y-axis scales, one for temperature and one for precipitation; these axes align 0mm of precipitation with 0 degrees of temp. The x axis shows 12 months, with the summer solstice placed in the center of the axis.

What is the species diversification rate hypothesis proposed to explain latitudinal variation in diversity?

This hypothesis proposes that in the tropics the rate of speciation is higher and the rate of extinctions is lower, resulting in an overall higher species diversity than in temperate or polar regions. 2 factors could account for a higher speciation rate in the tropics: a larger geographic area, and a warm and stable climate.

What is the productivity hypothesis proposed to explain latitudinal variation in diversity?

This hypothesis proposes that species diversification is promoted by higher productivity, which allows species more resources and thus decreased risk of species extinction due to competition. This might explain the positive relationship between seabird diversity and increasing latitude, given that ocean productivity is generally higher at temperate and polar latitudes.

What is the species diversification time hypothesis proposed to explain latitudinal variation in diversity?

This hypothesis proposes that the amount of time over which speciation has taken place is greatest in the tropics- in other words, that the tropics have a longer evolutionary history than temperate or polar regions. Thus, even if the rates of speciation and extinction are the same worldwide, the tropics should have accumulated more species over time simply because of the lack of dramatic changes in climate.

What is upwelling?

This is a process in which offshore winds in combination with the Coriolis effect push warmer surface waters away from the shore, allowing deeper, colder, and nutrient-rich bottom water to rise to the surface. This affects lack and regional climate on the coast by creating cooler and moister conditions. In addition, upwelled waters support high rates of primary production by phytoplankton, which in turn support dense consumer populations. Most of the world's great fisheries are concentrates in these zones.

What is migration?

This is a specific type of dispersal. It typically occurs in response to seasonal variation in resources, involves round-trip movement, and includes the whole population.

What is a full census?

This is an approach ecologists sometimes use to estimate population size and extent if the area is self-contained and small enough that they are able to simply count all the individuals of a particular species.

How does the topography of land play a large role in the regional and local physical environment, including climate?

This is because mountains create elevational gradients in temperature, precipitation and sunlight. For example, mountains show progressively colder temperatures and greater precipitation at higher elevations, creating different environmental conditions over relatively short distances. (also, rain shadows) Canyons and valleys also modify local climate in significant ways. (temperature inversions)

Why does the average global temperature vary with latitude, with warmer temperatures at the equator and colder temperatures at the poles?

This is due to the differences in solar energy input. This latitudinal variation in solar energy depends primarily on the angle of the sun's rays striking Earth. At high latitudes, incoming solar energy is distributed over a larger area (and thus is less intense) than at the equator, where sunlight strikes the surface perpendicularly

What is the Coriolis effect?

This is the deflection of air or water as a result of differences in Earth's rotational speed at different latitudes

What is evapotranspiration?

This is the evaporative transfer of heat and water from the surfaces of plants into the atmosphere, which reduces air temperature and increases moisture

What is the photic zone?

This is the layer of water reached by enough sunlight to support photosynthesis in both marine and freshwater environments

What is the ocean zone?

This is the layer of water which extends beyond the coastal zone

What is the coastal zone?

This is the layer of water which extends from the shoreline to the edge of the continental shelf. This zone is diverse and highly productive, supporting high densities of pelagic, or floating, plankton and fish. On the benthic or bottom of the ocean, this zone has a variety of living and nonliving habitats such as rocky reefs, soft sediment flats, coral reefs, and kelp bed.

What is biogeography?

This is the scientific study of the distribution and diversity of organisms on Earth. The patterns of this play out over global, regional, landscape, and local spacial scales. Spatial scales are interconnected in a hierarchical way, with patterns at one scale setting the conditions for patterns at other scales.

When does vicariance occur?

This occurs when a physical barrier prevents dispersal and divides a species into two or more discontinuous populations.

When does dispersal occur?

This occurs when the members of a species cross an existing barrier and establish a new population elsewhere.

What are temperature inversions?

Valleys can experience these, which are extremes in temperature that produce morning fog and intense afternoon heat. These occur when the valley concentrates heat from solar radiation during the day. As that heat rises, it forms an inversion layer that traps cold, dense, and moisture-laden air that descends into the valley overnight and produces fog

How does the topography of oceans influence the marine environment?

Variations in water depth affect light penetration, water temperature, water pressure, and water movement (waves and tides). These physical discontinuities create distinct zones that are identified principally by their physical conditions and the characteristic biota they contain, similar to the biomes on land. Water depth affects how much light is available to sustain the photosynthetic organisms that form the base of the marine food chain.

What is the theory of island biogeography?

Wilson and MacArthur teamed up to develop this theory to explain the pattern of specie-area relationships. They based their theory on 2 processes: the immigration of new species to an island and the extinction of species already present on that island. The premise is that the number of species on an island represents a balance between the rate at which species immigrate to and colonize the island and the rate at which resident species become locally extinct.

What are dispersal patterns?

Within a population, the spatial arrangement of individuals may vary in what are known as this.

Is there a hemisphere variation in temperature?

Yes, the Northern Hemisphere is slightly warmer and more variable in temperature than the Southern Hemisphere.

Earth's biomes are becoming smaller and more fragmented by local- and regional-scale forces such as what?

agriculture, deforestation, and urbanization. They are being transformed into island like habitats- isolated patches of suitable habitat such as parks or forest fragments, surrounded by extensive areas of unsuitable habitat.

How does dispersal serve as a mechanism to reduce the probability of local extinctions of populations?

by spreading the risk among multiple populations that are geographically separated by allowing individuals to escape a harsh physical environment

What is the equation that expresses the population growth rate, or the rate of change in population size over time?

delta N = (B-D) + (I-E)

What is the equation for the per capita growth rate?

delta N = rN0 where N= population size and r= per capita growth rate

Biogeographic regions reflect what?

evolutionary isolation

What does biotic mean?

living components of the environment. These components of an organism's environment are other organisms, so ecology includes the study of interactions within and among species.

How does Earth's topography influence freshwater environments?

it influences them through the depth of the water- but it also influences the degree and direction of movement of the water.

What is a population?

it is a group of individuals of the same species within a given area that have the potential to interbreed and interact with one another.

What is a community?

it is an assemblage of interacting species living together at the same place and time.

What is ecology?

it is the exploration of interconnections and is most simply defined as the study of the interrelationships among organisms and the physical environment. It is a science that generates knowledge about interactions in the natural world

What is environmentalism?

it is the use of ecological knowledge, along with economics, ethics, and many other considerations, to inform both personal decisions and public policy related to stewardship of the natural world

What is Earth's topography?

its shape and surface features, which has been formed over geological time and provides the basis for much of the variation in local and regional physical conditions

What does abiotic mean?

nonliving components of the environment. These components of an organism's environment are the myriad physical and chemical characteristics of the system

What is the albedo effect?

reflection of solar radiation is known as this

What is population dynamics?

the patterns and processes of population change over space and time. Growing crops, raising livestock, and controlling pests all involve paying attention to this.

What 3 main factors affect population dynamics?

the physical environment, biological interactions, and dispersal.

What is a rain shadow?

this is often created when a mountain range occurs adjacent to an ocean, where one side of the mountain has a wet climate and the other side has a dry climate. These occur when winds deliver moist air evaporated from the ocean to the windward side of the mountain, where the air rises, cools, and releases rain or snow. On the leeward side of the mountain, the now-dry air descends, warms, and produces arid conditions

What is dispersal?

this is simply the movement of individuals into (immigration) or out of (emigration) an existing population.

What is weather?

this is the short-term state of atmospheric conditions at a particular place and time. This is what you get on any one day. The responses of organisms to this are usually short-term (seeking shelter from a sudden storm, or shivering to keep warm when the temperature drops)

What is climate?

this refers to the average atmospheric conditions, and the extent of their variation, at a particular place over a longer time (years to millennia). This is what you expect given past conditions. This acts as a sort of filter for organisms, ultimately determining their distribution and abundance.

When is the term ecosystem often used?

this term is often used when describing a community of organisms in which their physical environment is explicitly taken into account. This type of ecology particularly focuses on the movement of energy and nutrients through a group of organisms

What is the biosphere?

ultimately, meta-ecosystems are linked to one another at larger geographic scales to form THIS, consisting of all living organisms on Earth plus their respective environments

The evolutionary separation of species can be attributed to what 2 basic processes?

vicariance and dispersal

What is a river?

water that flows downhill from its point of origin (the source) over the land surface as a result of gravity until it reaches either the ocean or a depression in Earth's surface, where it forms a lake or pond. The headwaters (those close to the source) tend to be cool, fast-flowing, and well oxygenated. As it flows downstream, it widens, it slows down, it warms, and sediment accumulates, reducing light penetration and oxygen levels.

Individuals of a population may be counted by making repeated counts with what two kinds of methods?

within a measured area called a quadrat or along a transect. By making repeated counts with either of these methods, investigators can use these surveys to make reasonably good estimates of the size of a population.

Does diversity vary with latitude and longitude?

yes