Which Factor Has The Greatest Effect On The Rate Of Evolution Of Animals

Biogeography

Biogeography is an ecological field of interest that focuses on the distribution of organisms and the abiotic factors that affect them.

Learning Objectives

Explicate the role of biogeography in the analysis of species distribution

Key Takeaways

Primal Points

• The limerick of constitute and animal communities change as abiotic factors, which include temperature and altitude, first to vary.
• Some species exist only in specific geographical areas while others can thrive in a variety of areas; however, no unmarried species can exist constitute everywhere in the earth.
• Studying an area where a species is non found is also of importance to ecologists in determining unique patterns of species distribution.
• As with animals, plant species tin also be either owned, commonly found in isolated land masses, or generalists, found in many regions.

Key Terms

• biogeography: the report of the geographical distribution of living things
• generalist: species which can thrive in a wide variety of environmental conditions
• endemic: unique to a particular surface area or region; not found in other places

Biogeography

Biogeography is the report of the geographic distribution of living things and the abiotic (non-living) factors that affect their distribution. Abiotic factors can include temperature, wet, nutrients, oxygen, and energy availability, besides equally disturbances from events such equally wind and burn. Differences in temperature and rainfall are primarily based on latitude and peak. As these abiotic factors change, the composition of plant and animal communities also changes. For case, if you were to begin a journey at the equator and walk north, yous would notice gradual changes in establish communities. At the start of your journey, you would see tropical wet forests with broad-leaved evergreen trees, which are characteristic of plant communities plant near the equator. Equally you lot continued to travel north, you would see these broad-leaved evergreen plants eventually give ascension to seasonally-dry forests with scattered trees. You would too begin to notice changes in temperature and moisture. At about 30 degrees north, these forests would give way to deserts, which are characterized by low atmospheric precipitation.

Moving farther north, you lot would come across that deserts are replaced past grasslands or prairies. Eventually, grasslands are replaced by deciduous temperate forests. These deciduous forests requite fashion to the boreal forests constitute in the subarctic, the expanse south of the Arctic Circle. Finally, you would reach the Arctic tundra, which is found at the most northern latitudes. This trek due north reveals gradual changes in both climate and the types of organisms that have adjusted to environmental factors associated with ecosystems found at different latitudes. However, dissimilar ecosystems be at the same latitude due in part to abiotic factors such as jet streams, the Gulf Stream, and ocean currents. If you were to hike up a mountain, the changes you would see in the vegetation would parallel those every bit you movement to higher latitudes.

Ecologists who written report biogeography examine patterns of species distribution. No species exists everywhere. For instance, the Venus flytrap is endemic to a pocket-size expanse in North and S Carolina. An endemic species is one which is naturally found only in a specific geographic area that is usually restricted in size. Other species are generalists, living in a broad variety of geographic areas. The raccoon, for instance, is native to nearly of Due north and Central America.

Species distribution patterns are based on biotic and abiotic factors and the influences these factors take had during the very long periods of time required for species evolution. Therefore, early on studies of biogeography were closely linked to the emergence of evolutionary thinking in the eighteenth century. Some of the almost distinctive assemblages of plants and animals occur in regions that have been physically separated for millions of years past geographic barriers. Biologists estimate that Australia, for instance, has between 600,000 and 700,000 species of plants and animals. Approximately 3/4 of living plant and mammal species are endemic species plant solely in Australia.

Endemic species of Australia: Australia is habitation to many endemic species. The (a) wallaby (Wallabia bicolor), a medium-sized fellow member of the kangaroo family, is a pouched mammal, or marsupial. The (b) echidna (Tachyglossus aculeatus) is an egg-laying mammal.

Sometimes ecologists discover unique patterns of species distribution past determining where species are non found. Hawaii, for example, has no native land species of reptiles or amphibians and has only ane native terrestrial mammal, the hoary bat. Most of New Guinea, as another case, lacks placental mammals.

Plants can be owned or generalists. Owned plants are found simply in specific regions of the globe, while generalists are constitute in many regions. Isolated land masses, such every bit Australia, Hawaii, and Madagascar, often have large numbers of owned plant species. Some of these plants are endangered due to man activity. The wood gardenia (Gardenia brighamii), for instance, is endemic to Hawaii; only an estimated fifteen–20 trees are thought to be.

Endangered wood gardenia: Listed equally federally endangered, the forest gardenia is a small tree with distinctive flowers. Information technology is found only in five of the Hawaiian Islands in small populations consisting of a few individual specimens.

Energy Sources

The availability of energy and nutrient sources affects species distribution and their adaptation to state or aquatic habitats.

Learning Objectives

Assess how energy availability affects species distribution within an ecosystem

Key Takeaways

Key Points

• In country habitats, institute adaptations include life cycles that are dependent on the availability of low-cal; for example, species will flower or grow at varying times to ensure they capture enough available lite suitable to their needs.
• In aquatic ecosystems, species growth and distribution are adapted to bargain with the sometimes-limited availability of light due to its absorption past water, plants, suspended particles, microorganisms, and h2o depth.
• Ocean upwelling and spring and fall turnovers are of import processes regulating the distribution of nutrients in an aquatic ecosystems.
• Nutrient availability is continued to the free energy needs of organisms in aquatic ecosystems since sequestered free energy is reused past living organisms from expressionless ones.

Primal Terms

• ephemeral: lasting for a short period of fourth dimension
• upwelling: the oceanographic phenomenon that occurs when stiff, unremarkably seasonal, winds push h2o abroad from the coast, bringing cold, nutrient-rich deep waters up to the surface
• thermocline: a layer inside a body of water or air where the temperature changes quickly with depth

Energy Availability & Nutrient Cycling equally Abiotic Factors

Energy Sources

Energy from the sunday is captured by greenish plants, algae, blue-green alga, and photosynthetic protists. These organisms convert solar energy into the chemical free energy needed by all living things. Lite availability can be an important abiotic force direct affecting the evolution of adaptations in photosynthesizers. For instance, plants in the understory of a temperate forest are shaded when the trees to a higher place them in the canopy completely foliage out in the late spring. Not surprisingly, understory plants have adaptations to successfully capture bachelor light. One such adaptation is the rapid growth of spring ephemeral plants, such equally the leap dazzler. These spring flowers achieve much of their growth and terminate their life bicycle (reproduce) early in the season before the trees in the awning develop leaves.

Imperceptible plant: The bound beauty is an imperceptible bound institute that flowers early in the spring to avoid competing with larger forest copse for sunlight.

In aquatic ecosystems, the availability of light may be limited because sunlight is absorbed by water, plants, suspended particles, and resident microorganisms. Toward the bottom of a lake, swimming, or ocean, there is a zone that light cannot reach. Photosynthesis cannot have identify in that location and, as a result, a number of adaptations take evolved that enable living things to survive without light. For instance, aquatic plants have photosynthetic tissue near the surface of the h2o. The wide, floating leaves of a water lily cannot survive without light. In environments such as hydrothermal vents, some bacteria excerpt energy from inorganic chemicals because in that location is no lite for photosynthesis.

Nutrient Cycling

The availability of nutrients in aquatic systems is too an important aspect of free energy or photosynthesis. Many organisms sink to the bottom of the ocean when they die in the open water. When this occurs, the energy found in that organism is sequestered for some time unless body of water upwelling occurs. Ocean upwelling is the ascent of deep ocean waters that occurs when prevailing winds accident along surface waters nearly a coastline. As the wind pushes ocean waters offshore, water from the lesser of the ocean moves upwards to supersede this water. As a event, the nutrients once contained in dead organisms become available for reuse past other living organisms.

Upwelling: Body of water upwelling is an important process that recycles nutrients and energy in the bounding main. As wind (green arrows) pushes offshore, it causes water from the sea bottom (red arrows) to movement to the surface, bringing upwards nutrients from the ocean depths.

In freshwater systems, the recycling of nutrients occurs in response to air temperature changes. The nutrients at the bottom of lakes are recycled twice each year: in the bound and autumn turnover, which recycles nutrients and oxygen from the bottom of a freshwater ecosystem to the top of a body of water. These turnovers are acquired by the formation of a thermocline: a layer of h2o with a temperature that is significantly unlike from that of the surrounding layers. In wintertime, the surface of lakes found in many northern regions is frozen. Nevertheless, the h2o nether the water ice is slightly warmer, while the water at the bottom of the lake is warmer even so at 4 °C to 5 °C (39.2 °F to 41 °F). Water is densest at four °C; therefore, the deepest water is also the densest. The deepest h2o is oxygen poor because the decomposition of organic material at the bottom of the lake uses up bachelor oxygen that cannot be replaced by ways of oxygen diffusion into the water due to the surface ice layer.

In springtime, air temperatures increment and surface ice melts. When the temperature of the surface water begins to attain iv °C, the water becomes heavier and sinks to the bottom. The water at the bottom of the lake, displaced by the heavier surface water, rises to the tiptop. Equally it rises, the sediments and nutrients from the lake lesser are brought forth with it. During the summer months, the lake water stratifies, or forms layers, with the warmest water at the lake surface.

As air temperatures driblet in the autumn, the temperature of the lake water cools to iv °C; this causes fall turnover as the heavy cold h2o sinks and displaces the water at the bottom. The oxygen-rich water at the surface of the lake and so moves to the bottom of the lake, while the nutrients at the bottom of the lake rising to the surface (). During the wintertime, the oxygen at the bottom of the lake is used by decomposers and other organisms requiring oxygen, such equally fish.

Nurient recycling in freshwater systems: The spring and fall turnovers are of import processes in freshwater lakes that act to move the nutrients and oxygen at the bottom of deep lakes to the top. Turnover occurs because h2o has a maximum density at 4 °C. Surface water temperature changes as the seasons progress, causing denser water to sink.

Temperature and Water

Temperature and water are of import abiotic factors that affect species distribution.

Learning Objectives

Depict species adaptations to temperature fluctuations and the availability of water

Key Takeaways

Key Points

• Temperature is a factor that influences species distribution because organisms must either maintain a specific internal temperature or inhabit an environment that volition go along the body inside a temperature range that supports their metabolism.
• Many species accept developed adaptations, such equally migration, hibernation, and estivation, to deal with temperature fluctuations in the environments in which they live.
• Water retentiveness is vital to all living beings; adaptations have evolved inside both terrestrial and aquatic species to minimize water loss.

Key Terms

• osmosis: The net motion of solvent molecules from a region of loftier solvent potential to a region of lower solvent potential through a partially permeable membrane
• estivate: to go into stasis or torpor in the summer months
• extremophile: an organism that lives nether farthermost conditions of temperature, salinity, etc; commercially of import as a source of enzymes that operate under similar weather condition
• torpor: a state of being inactive or stuporous
• hibernation: a state of inactivity and metabolic low in animals during winter

Temperature & Water as Abiotic Influences

Temperature

Temperature affects the physiology of living things besides as the density and state of water. It exerts an important influence on living organisms considering few can survive at temperatures below 0 °C (32 °F) due to metabolic constraints. Information technology is besides rare for them to survive at temperatures exceeding 45 °C (113 °F). This is a reflection of evolutionary response to typical temperatures. Enzymes are most efficient within a narrow and specific range of temperatures; enzyme deposition can occur at higher temperatures. Therefore, organisms must either maintain an internal temperature or inhabit an surround that will go along the body within a temperature range that supports metabolism. Some animals have adapted to enable their bodies to survive significant temperature fluctuations, as seen in hibernation or reptilian torpor. Similarly, some bacteria have adapted to survive in extremely-hot temperatures found in places such as geysers. Such bacteria are examples of extremophiles: organisms that thrive in extreme environments.

Temperature tin can limit the distribution of living things. Animals faced with temperature fluctuations may respond with adaptations, such as migration, in order to survive. Migration, the motility from one place to another, is mutual in animals, including many that inhabit seasonally-cold climates. Migration solves problems related to temperature, locating food, and finding a mate. In migration, for instance, the arctic tern (Sterna paradisaea) makes a twoscore,000 km (24,000 mi) round trip flight each year betwixt its feeding grounds in the southern hemisphere and its breeding grounds in the Arctic Bounding main. Monarch butterflies (Danaus plexippus) live in the eastern United States in the warmer months, but migrate to Mexico and the southern Usa in the wintertime. Some species of mammals also make migratory forays: reindeer (Rangifer tarandus) travel about 5,000 km (three,100 mi) each year to find food. Amphibians and reptiles are more than limited in their distribution because they lack migratory ability. Not all animals that tin migrate exercise so as migration carries risk and comes at a loftier energy cost.

Chill tern: The chill tern is an example of a species that must drift yearly to deal with temperature fluctuations that exist in the regions where it is found.

Some animals hide or estivate to survive hostile temperatures. Hibernation enables animals to survive cold conditions, while estivation allows animals to survive the hostile conditions of a hot, dry out climate. Animals that hide or estivate enter a country known as torpor, a condition in which their metabolic rate is significantly lowered. This enables the animal to wait until its environment better supports its survival. Some amphibians, such as the wood frog (Rana sylvatica), take an antifreeze-similar chemical in their cells, which retains the cells' integrity and prevents them from bursting.

Wood frog: The woods frog, like all other amphibians and reptiles, cannot drift; equally a result, the species survives extreme temperature changes through the antifreeze-similar chemical found in their cells.

Water

H2o is required past all living things because it is disquisitional for cellular processes. Since terrestrial organisms lose water to the environment by elementary improvidence, they have evolved many adaptations to retain water.

Examples of adaptations used by terrestrial and aquatic species include the following:

• Plants have a number of interesting features on their leaves, such as leaf hairs and a waxy cuticle, that serve to decrease the rate of water loss via transpiration.
• Freshwater organisms, surrounded by water, are constantly in danger of having h2o blitz into their cells because of osmosis. Many adaptations of organisms living in freshwater environments have evolved to ensure that solute concentrations in their bodies remain within appropriate levels. 1 such accommodation is the excretion of dilute urine.
• Marine organisms are surrounded by h2o with a college solute concentration than the organism and, thus, are in danger of losing water to the environment because of osmosis. These organisms have morphological and physiological adaptations to retain water and release solutes into the environment. For case, marine iguanas (Amblyrhynchus cristatus) sneeze out h2o vapor that is loftier in salt in society to maintain solute concentrations within an acceptable range while swimming in the ocean and eating marine plants.

Marine iguanas: Marine iguanas accept a special, common salt-secretion adaption that allows them to minimize bodily h2o loss.

Inorganic Nutrients and Other Factors

Soil construction, oxygen availability, wind, and fire are abiotic factors that have influences on species distribution and quantity.

Learning Objectives

Identify further abiotic factors that affect species distribution and abundance

Key Takeaways

Key Points

• Soil structure, pH, and its nutrient content affect the distribution of plants, which in plough influences the distribution of the animals that feed on them.
• Oxygen availability is an important abiotic gene affecting species in both aquatic and terrestrial environments.
• Current of air and fire impose physical disturbances that species must exist adjusted to in social club to live in afflicted areas.

Key Terms

• inorganic: relating to a chemical compound that does non contain carbon
• transpiration: the loss of water by evaporation in terrestrial plants, specially through the stomata; accompanied past a respective uptake from the roots

Other Important Abiotic Factors

Inorganic nutrients, soil structure, and aquatic oxygen availability are farther abiotic factors that touch species distribution in an ecosystem. The aforementioned is true for terrestrial factors, such equally wind and fire, which tin bear on the types of species that inhabit regions exposed to these types of disturbances.

Inorganic Nutrients and Soil

Inorganic nutrients, such equally nitrogen and phosphorus, are of import in the distribution and the abundance of living things. Plants obtain these inorganic nutrients from the soil when water moves into the plant through the roots. Therefore, soil structure (the particle size of soil components), soil pH, and soil food content play an important office in the distribution of plants. Animals obtain inorganic nutrients from the food they consume. Therefore, animal distributions are related to the distribution of what they consume. In some cases, animals will follow their nutrient resource as it moves through the surroundings.

Oxygen Availability

Jack pine cones: The mature cones of the jack pine (Pinus banksiana) open only when exposed to high temperatures, such equally during a forest fire. A burn will probably impale most vegetation, so a seedling that germinates after a burn is more likely to receive ample sunlight than one that germinates under normal conditions.

Some abiotic factors, such as oxygen, are important in aquatic ecosystems as well as terrestrial environments. Terrestrial animals obtain oxygen from the air they breathe. Oxygen availability can be an outcome for organisms living at very high elevations, where there are fewer molecules of oxygen in the air. In aquatic systems, the concentration of dissolved oxygen is related to h2o temperature and the speed at which the water moves. Cold h2o has more than dissolved oxygen than warmer h2o. In improver, salinity, water current, and tide tin be important abiotic factors in aquatic ecosystems.

Other Terrestrial Factors

Wind tin be an important abiotic factor because it influences the rate of evaporation and transpiration. The physical force of wind is besides of import because it tin can move soil, water, or other abiotic factors, as well as an ecosystem's organisms.

Burn down is another terrestrial factor that can be an of import agent of disturbance in terrestrial ecosystems. Some organisms are adapted to fire and, thus, require the high heat associated with fire to complete a part of their life cycle. For example, the jack pino, a coniferous tree, requires rut from burn down for its seed cones to open. Through the called-for of pine needles, fire adds nitrogen to the soil and limits competition by destroying undergrowth.

Abiotic Factors Influencing Establish Growth

The ii most of import abiotic factors affecting plant primary productivity in an ecosystem are temperature and moisture.

Learning Objectives

Identify the abiotic factors that touch found growth

Central Takeaways

Key Points

• Primary production, on which nearly all of life on globe is dependent, occurs through either photosynthesis or chemosynthesis.
• Annual biomass product, used to judge net primary productivity past plants in an expanse, is directly influenced by an environment's abiotic factors, which include temperature and moisture.
• Warm and wet climates have the greatest amount of institute biomass because they offer conditions in which photosynthesis, institute growth, and the resulting internet primary productivity are highest.

Cardinal Terms

• biomass: the total mass of all living things within a specific area, habitat, etc.
• eco-region: a region, smaller than an ecozone, that contains a distinct biodiversity of flora and beast
• chemosynthesis: the production of carbohydrates and other compounds using the oxidation of chemical nutrients every bit a source of energy rather than sunlight; information technology is limited to certain bacteria and fungi

Abiotic Factors Influencing Constitute Growth

Temperature and moisture are of import influences on plant production (chief productivity) and the amount of organic matter bachelor as nutrient (net primary productivity). Primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses calorie-free as its source of energy, but it also occurs through chemosynthesis, which uses the oxidation or reduction of chemical compounds as its source of energy. Almost all life on earth is directly or indirectly reliant on primary production. The organisms responsible for primary production, known as primary producers or autotrophs, form the base of the food chain. In terrestrial eco-regions, these are mainly plants, while in aquatic eco-regions, they are mainly algae.

Net principal productivity is an estimation of all of the organic matter available as food. Information technology is calculated as the total amount of carbon stock-still per yr minus the amount that is oxidized during cellular respiration. In terrestrial environments, net master productivity is estimated by measuring the aboveground biomass per unit surface area, which is the full mass of living plants, excluding roots. This means that a large percentage of plant biomass which exists undercover is not included in this measurement. Cyberspace primary productivity is an important variable when considering differences in biomes. Very productive biomes accept a high level of aboveground biomass.

Annual biomass production is directly related to the abiotic components of the environment. Environments with the greatest amount of biomass have weather in which photosynthesis, plant growth, and the resulting net principal productivity are optimized. The climate of these areas is warm and wet. Photosynthesis can proceed at a high rate, enzymes can work most efficiently, and stomata can remain open without the take a chance of excessive transpiration. Together, these factors lead to the maximal corporeality of carbon dioxide (CO₂) moving into the plant, resulting in high biomass production. The aboveground biomass produces several of import resources for other living things, including habitat and nutrient. Conversely, dry and cold environments have lower photosynthetic rates and, therefore, less biomass. The animal communities living there volition as well be affected by the decrease in available food.

Principal productivity and biomass production: The magnitude and distribution of global primary product varies between biomes. Still, warm and wet climates have the greatest corporeality of almanac biomass production.

Source: https://courses.lumenlearning.com/boundless-biology/chapter/biogeography/

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