Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Chapter 52 An Introduction to Ecology and the Biosphere Ecology - interactions between organisms and the environment

Fig Organismal ecology Population ecology Community ecology Ecosystem ecology Landscape ecology Global ecology

Fig Why is species X absent from an area? Does dispersal limit its distribution? Does behavior limit its distribution? Area inaccessible or insufficient time Yes No Yes Habitat selection Do biotic factors (other species) limit its distribution? Predation, parasitism, competition, disease Do abiotic factors limit its distribution? Chemical factors Physical factors Water Oxygen Salinity pH Soil nutrients, etc. Temperature Light Soil structure Fire Moisture, etc. Biogeography - good starting point for understanding what limits geographic distribution of species Two kinds of factors that determine distribution: biotic, or living factors, and abiotic, or nonliving factors

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Dispersal and Distribution Dispersal - movement of individuals away from centers of high population density or from their area of origin

Fig Current Natural range expansions show the influence of dispersal on distribution

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Species Transplants Species transplants include organisms that are intentionally or accidentally relocated from their original distribution Species transplants can disrupt the communities or ecosystems to which they have been introduced

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Behavior and Habitat Selection Some organisms do not occupy all of their potential range Species distribution may be limited by habitat selection behavior

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Biotic and Abiotic Factors Biotic factors that affect the distribution of organisms may include: – Interactions with other species – Predation – Competition Abiotic factors affecting distribution of organisms include: – Temperature – Water – Sunlight – Wind – Rocks and soil Most vary in space and time

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Temperature Environmental temperature is an important factor in distribution of organisms because of its effects on biological processes Cells may freeze and rupture below 0°C, while most proteins denature above 45°C Mammals and birds expend energy to regulate their internal temperature

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Water Water availability in habitats is another important factor in species distribution Desert organisms exhibit adaptations for water conservation

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Salinity Salt concentration affects water balance of organisms through osmosis Few terrestrial organisms are adapted to high- salinity habitats

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Sunlight Light intensity and quality affect photosynthesis Water absorbs light, thus in aquatic environments most photosynthesis occurs near the surface In deserts, high light levels increase temperature and can stress plants and animals

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Rocks and Soil Many characteristics of soil limit distribution of plants and thus the animals that feed upon them: – Physical structure – pH – Mineral composition

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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 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

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Global Climate Patterns Global climate patterns are determined largely by solar energy and the planet’s movement in space Sunlight intensity plays a major part in determining the Earth’s climate patterns More heat and light per unit of surface area reach the tropics than the high latitudes Seasonal variations of light and temperature increase steadily toward the poles Global air circulation and precipitation patterns play major roles in determining climate patterns Warm wet air flows from the tropics toward the poles

Fig a Latitudinal Variation in Sunlight Intensity Low angle of incoming sunlight Sun directly overhead at equinoxes Low angle of incoming sunlight Atmosphere 90ºS (South Pole) 60ºS 30ºS 23.5ºS (Tropic of Capricorn) 0º (equator) 30ºN 23.5ºN (Tropic of Cancer) 60ºN 90ºN (North Pole) Seasonal Variation in Sunlight Intensity 60ºN 30ºN 30ºS 0º (equator) March equinox June solstice Constant tilt of 23.5º September equinox December solstice

Fig d Global Air Circulation and Precipitation Patterns 60ºN 30ºN 0º (equator) 30ºS 60ºS Global Wind Patterns Descending dry air absorbs moisture Ascending moist air releases moisture Descending dry air absorbs moisture Arid zone Tropics Arid zone 0º 66.5ºN (Arctic Circle) 60ºN 30ºN 0º (equator) 30ºS 60ºS 66.5ºS (Antarctic Circle) Westerlies Northeast trades Doldrums Southeast trades Westerlies 23.5º 30º 23.5º 30º

Fig Warm air over land rises Air cools at high elevation. Cool air over water moves inland, replacing rising warm air over land. Cooler air sinks over water.

Fig Wind direction Mountain range Leeward side of mountain Ocean Mountains have a significant effect on Amount of sunlight reaching an area Local temperature Rainfall

Fig Littoral zone Limnetic zone Photic zone Pelagic zone Benthic zone Aphotic zone 2,000–6,000 m Abyssal zone Benthic zone Aphotic zone Pelagic zone Continental shelf 200 m Photic zone 0 Oceanic zone Neritic zone Intertidal zone Many aquatic biomes are stratified into zones or layers defined by light penetration, temperature, and depth Photic zone (photosynthesis) and aphotic zone (little light) Benthic zone - organic and inorganic sediment at the bottom of all aquatic Benthos - communities of organisms Detritus - dead organic matter; important source of food

Fig Winter 4º 4ºC 4º Spring Summer Autumn Thermocline 4º 4ºC 4º 4ºC 2º 0º 4ºC 5º 6º 8º 18º 20º 22º Thermocline separates the warm upper layer from the cold deeper water Turnover - semiannual mixing of their waters mixes oxygenated water from the surface with nutrient-rich water from the bottom

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Major aquatic biomes can be characterized by their physical environment, chemical environment, geological features, photosynthetic organisms, and heterotrophs Oligotrophic lakes - nutrient-poor and generally oxygen-rich Eutrophic lakes - nutrient-rich and often depleted of oxygen if ice covered in winter Wetland - inundated by water at least some of the time – supports plants adapted to water-saturated soil – among the most productive biomes on earth Streams and Rivers – most prominent physical characteristic is current

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Estuary – transition area between river and sea – Salinity varies with the rise and fall of the tides – nutrient rich and highly productive Intertidal zone – periodically submerged and exposed by the tides – challenged by variations in temperature and salinity and mechanical forces

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 52.4: The structure and distribution of terrestrial biomes are controlled by climate and disturbance Climate is very important in determining why terrestrial biomes are found in certain areas Biome patterns can be modified by disturbance such as a storm, fire, or human activity

Fig Tropical forest Savanna Desert Chaparral Temperate grassland Temperate broadleaf forest Northern coniferous forest Tundra High mountains Polar ice 30ºN Tropic of Cancer Equator Tropic of Capricorn 30ºS

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Climate and Terrestrial Biomes Climate has a great impact on the distribution of organisms This can be illustrated with a climograph, a plot of the temperature and precipitation in a region Biomes are affected not just by average temperature and precipitation, but also by the pattern of temperature and precipitation through the year

Fig Tropical forest Temperate grassland Desert Temperate broadleaf forest Northern coniferous forest Arctic and alpine tundra Annual mean temperature (ºC) Annual mean precipitation (cm) –

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings General Features of Terrestrial Biomes and the Role of Disturbance Terrestrial biomes are often named for major physical or climatic factors and for vegetation Terrestrial biomes usually grade into each other, without sharp boundaries The area of intergradation, called an ecotone, may be wide or narrow Layering of vegetation in all biomes provides diverse habitats for animals