I. Concept 52.2: Interactions between organisms and the environment limit the distribution of species a. Ecologists have long recognized global and regional patterns of distribution of organisms within the biosphere b. Biogeography is a good starting point for understanding what limits geographic distribution of species c. Ecologists recognize two kinds of factors that determine distribution:

______, or living factors, and ______, or nonliving factors d. Ecologists consider multiple factors when attempting to explain the distribution of species d.i. Dispersal is movement of individuals away from centers of

______or from their area of origin d.i.1. Dispersal contributes to global distribution of organisms e. Natural range expansions show the influence of dispersal on distribution

f. Species ______include organisms that are intentionally or accidentally relocated from their original distribution f.i. Species transplants can disrupt the communities or ecosystems to which they have been introduced g. Some organisms do not occupy all of their potential range h. Species distribution may be limited by habitat selection behavior i. Biotic factors that affect the distribution of organisms may include: i.i. Interactions with other species i.ii. Predation

i.iii. ______i.iv. Abiotic Factors

i.iv.1. ______i.iv.2. Water i.iv.3. Sunlight

i.iv.4. ______i.iv.5. Rocks and soil i.iv.5.a. Most abiotic factors vary in space and time j. Environmental temperature is an important factor in distribution of organisms because of its effects on biological processes j.i. Cells may freeze and rupture below 0°C, while most proteins ______above 45°C j.ii. Mammals and birds expend energy to regulate their internal temperature k. Water availability in habitats is another important factor in species distribution k.i. Desert organisms exhibit adaptations for water conservation l. Salt concentration affects water balance of organisms through

______l.i. Few terrestrial organisms are adapted to high-salinity habitats m. Light intensity and quality affect photosynthesis m.i. Water absorbs light, thus in aquatic environments most

photosynthesis occurs ______m.ii. In deserts, high light levels increase temperature and can stress plants and animals n. Many characteristics of soil limit distribution of plants and thus the animals that feed upon them:

n.i. ______n.ii. pH n.iii. Mineral composition n.iv. Climate n.iv.1. Four major abiotic components of ______are temperature, water, sunlight, and wind n.iv.1.a. The long-term prevailing weather conditions in an area constitute its climate n.iv.2. Macroclimate consists of patterns on the global, regional, and local level

n.iv.3. ______consists of very fine patterns, such as those encountered by the community of organisms underneath a fallen log o. Global climate patterns are determined largely by solar energy and the planet’s movement in space p. Sunlight intensity plays a major part in determining the Earth’s climate patterns p.i. More heat and light per unit of surface area reach the tropics than the high latitudes p.ii. Seasonal variations of light and temperature increase steadily toward the poles p.iii. Global air circulation and precipitation patterns play major roles in determining climate patterns p.iii.1. Warm wet air flows from the tropics toward the poles p.iii.2. Air flowing close to Earth’s surface creates predictable global wind patterns p.iii.3. Cooling trade winds blow from east to west in the tropics; prevailing westerlies blow from west to east in the temperate zones q. Proximity to bodies of water and topographic features contribute to local variations in climate r. Seasonal variation also influences climate s. The Gulf Stream carries warm water from the equator to the North Atlantic s.i. Oceans and their currents and large lakes moderate the climate of nearby terrestrial environments s.ii. During the day, air rises over warm land and draws a cool breeze from the water across the land s.iii. As the land cools at night, air rises over the warmer water and draws cooler air from land back over the water, which is replaced by warm air from offshore t. Mountains have a significant effect on t.i. The amount of sunlight reaching an area t.i.1. Local temperature t.i.2. Rainfall t.i.3. Rising air releases moisture on the windward side of a peak and creates a “rain shadow” as it absorbs moisture on the leeward side u. The angle of the sun leads to many seasonal changes in local environments u.i. Lakes are sensitive to seasonal temperature change and experience seasonal turnover u.ii. Microclimate is determined by fine-scale differences in the environment that affect light and wind patterns v. Global climate change will profoundly affect the biosphere v.i. One way to predict future global climate change is to study previous changes v.i.1. As glaciers began retreating 16,000 years ago, tree distribution patterns changed v.i.2. As climate changes, species that have difficulty dispersing may have smaller ranges or could become extinct Lecture Questions 52.2 Interactions between Organisms and the Environment Limit the Distribution of Species 1. Explain how dispersal may contribute to a species’ distribution.

2. Describe, with examples, how biotic and abiotic factors may affect the distribution of organisms.

3. Describe how an ecologist might predict the effect of global warming on distribution of a tree species.