Communities, Biomes, and Ecosystems Chapter 3 Communities, Biomes, and Ecosystems

Section 3.1: Community Ecology All living organisms are limited by factors in the environment Communities A group of interacting populations that occupy the same area at the same time Includes biotic factors: plants, other animals, bacteria, fungi, etc. and the abiotic factors: rocks, water, soil, air, pH, temperature, etc.

Communities Not every community includes the same variety of organisms Urban vs. rural Desert vs. arctic

Communities Organisms adapt to the conditions in which they live

Communities Limiting factors – any abiotic or biotic factor that restricts the numbers, reproduction, or distribution of organisms Abiotic limiting factors: sunlight, climate, temperature, water, nutrients, fire, soil, space Biotic limiting factors: living things such as other plant and animal species

Communities Range of tolerance Upper limit and lower limit for any environmental factor that defines the conditions in which an organism can survive Tolerance: the ability of any organism to survive when subjected to abiotic or biotic factors Figure 3.2 example Steelhead trout page 61

Ecological Succession Ecosystems are constantly changing The change in an ecosystem that happens when one community replaces another as a result of changing abiotic and biotic factors is ecological succession two types – Primary succession Secondary succession

Primary Succession The establishment of a community in an area of exposed rock that does not have topsoil Usually occurs slowly at first Usually consists of bacteria and perhaps fungi, small plants, lichens, grasses, and perennial herbs

Primary Succession Most plants require soil for growth Pioneer species help create soil by secreting acids that help break down rocks As pioneer organisms die, their decaying organic matter, along with bits of sediment from the rocks, make up the first stage of soil development

Primary Succession Once soil is established, other organisms can grow in the newly formed soil Eventually, enough soil is present to support shrubs and trees A mature community can eventually develop from bare rock. Stable mature community that has little change in the composition of species is called a climax community A true climax community is unlikely to occur due to ongoing changes

Secondary Succession Disturbances such as fire, flood, or a windstorm can disrupt a community Creates new species Over time, secondary succession: the orderly and predictable change that takes place after a community of organisms has been removed but the soil has remained intact - occurs

Secondary Succession Pioneer species – mainly plants that begin to grow in the distributed area- are the first species to start secondary succession where the community changes over time

Succession’s End Point Ecological succession is likely a very complex process that involves many factors Cannot be predicted Constant change at different rates Very slow process Human interaction a factor Difficult to determine

Section 3.2: Terrestrial Biomes Ecosystems on land are grouped into biomes primarily based on the plant communities within them Effects of Latitude and Climate are a factor Weather is a condition of atmosphere at a specific place and time

Effects of Latitude and Climate Latitude – the distance of any point on the surface of Earth north or south from the equator Ranges from 0 degrees at the equator to 90 degrees at the poles Sun strikes Earth more directly at the equator Earth’s surface is heated differently in different areas (polar, temperate, & tropical zones)

Climate The average weather conditions in an area, including temperature and precipitation Latitude has a large effect Winds and ocean currents also play a role Reminder: A biome is a large group of ecosystems that share the same climate and have similar types of communities

Climate Global warming – result of the greenhouse effect

Major Land Biomes Biomes are classified primarily according to the characteristics of their plants Also characterized by temperature Precipitation Animal species

Terrestrial Biomes Tundra Boreal forest (Taiga) Temperate forest Temperate woodland and shrubland Temperate grassland Desert Tropical savanna Tropical seasonal forest Tropical rain forest

Tundra Below polar ice caps across northern North America, Europe, and Siberia in Asia Treeless biome with a layer of permafrost Figure 3.8 on page 68

Boreal Forest (Taiga) South of tundra Evergreen forest Figure 3.9 on page 68

Temperate Forest Southeastern Canada, eastern US, most of Europe, parts of Asia and Australia Composed mostly of broad-leaved, deciduous trees Figure 3.10 on page 69

Temperate Woodland and Shrubland Areas surrounding the Mediterranean Sea, western coasts of North and South America, South Africa and Australia Chaparral – dominated by shrubs Figure 3.11 on page 69

Temperate Grassland Fertile soil Called steppes, prairies, pampas, llanos, cerrados, savannas, rangelands or velds Figure 3.12 on page 70

Desert Exist on every continent except Europe Figure 3.13 on page 70

Tropical Savanna Characterized by grasses and scattered trees Occur in Africa, South America, and Australia Figure 3.14 on page 71

Tropical Seasonal Forest Tropical dry forests found in Africa, Asia, Australia, and South and Central America Resemble temperate deciduous forest during dry season Figure 3.15 on page 71

Tropical Rain Forest Found in Central and South America, southern Asia, western Africa, and northeastern Australia Figure 3.16 on page 72

Other Terrestrial Areas Mountains Polar regions

Biome Activity On the index cards provided put one biome on each side of the index card Be sure to include the information found in Figures 3.8 - 3.16 for each biome Use these cards as a study tool for your upcoming test

Section 3.3: Aquatic Ecosystems Aquatic ecosystems are grouped based on abiotic factors such as water flow, depth, distance from shore, salinity, and latitude

The Water on Earth Largely covered by water Includes freshwater, transitional, and marine aquatic ecosystems

Freshwater Ecosystems Includes ponds, lakes, streams, rivers and wetlands Plants and animals are adapted to the low salt content in freshwater and unable to survive in areas of high salt concentration About 2.5% of water on Earth is freshwater

Freshwater Ecosystems Of the 2.5% of freshwater 68.9% is in glaciers 30.8% in groundwater 0.3% in lakes, ponds, rivers, streams and wetlands Almost all freshwater species live here

Rivers and Streams Water flows in one direction Begins at source (headwater) and travels to the mouth Empties into a larger body of water May start from underground springs or snowmelts Slope of landscape determines direction and speed of water flow

Rivers and Streams When slope is steep, water flows quickly causing a lot of sediment to be picked up and carried by the water As slope levels, speed of water flow decreases and sediment deposited in form of silt, mud and sand

Rivers and Streams Interactions between wind and water adds oxygen Interactions between land and water results in erosion Currents or turbulence prevents much accumulation of organic materials and sediment More species found in slow-moving water

Lakes and Ponds Inland body of standing water Can be small or large Seasonal temperature changes and wind mixes top and bottom layers -oxygenating it and bringing nutrients to top Oligotrophic – nutrient-poor lake Often found in mountains

Lakes and Ponds Eutrophic - nutrient-rich lake Usually found at lower altitudes More plant and animal species present

Lakes and Ponds Divided into three zones based on amount of sunlight that penetrates the water Littoral zone – area closest to shore Limnetic zone – open water area that is well lit and dominated by plankton Profundal zone – minimal light, deepest area of lake

Transitional Aquatic Ecosystems Wetlands : areas of lands such as marshes, swamps, and bogs Saturated with water and support aquatic plants Estuaries: among most diverse ecosystems Formed where freshwater from a river or stream merges with salt water from the ocean

Transitional Aquatic Ecosystems Salt marshes are similar to estuaries Support seagrasses, shrimp, shellfish

Marine Ecosystems Intertidal zone: a narrow band where the ocean meets land Further divided based on communities that exist in each zone Spray zone High-tide zone Mid-tide zone Low-tide zone Page 79 Figure 3.26

Marine Ecosystems Open ocean ecosystems Photic zone(pelagic zone, euphotic zone): shallow, sunlight penetrates Aphotic zone: below photic zone, sunlight unable to penetrate, dark and generally cold Benthic zone: along ocean floor Abyssal zone: deepest region of ocean, very cold

Open Ocean Ecosystems

Coastal Ocean and Coral Reefs Sensitive to changes in environment Often studied Southern tip of Florida among world’s most diverse