Community Ecology In communities, populations can interact with each other & species can live closely with other species. Many species have evolved special adaptations that help them survive within their communities. Clown fish have a protective coating of mucus on their bodies that keep them from being stung by anemone. The Morgan’s sphinx moth has a 30cm proboscis, allowing it to pollinate Darwin’s orchid, where the nectar is 30cm deep.

Community Ecology These are adaptations that help the species survive with the other species in an area. What types of adaptations would help a species survive in their abiotic environment? The adaptations needed depends on the type of ecosystem the species lives in.

The Biomes on Earth A biome is a group of ecosystems with the same climate and similar communities. Tropical Rain Forest Temperate Grasslands Tropical Savanna Temperate Forest Desert Boreal Forest (Taiga) Tundra

Tropical Rain Forests Inhabit more than half of the world’s plants & animals – Hot & wet – Dense plant growth allowing very little light to reach the soil – Thin, nutrient poor soil – Lie along the equator

Tropical Rain Forests Canopy – dense covering formed by tall trees Understory – shorter trees & vines

Tropical Savanna (Grasslands) Covered by grasses and few isolated trees & shrubs – Warm temperatures – Frequent fires set by lightning igniting the dry grass – Found in parts of Eastern Africa, southern Brazil, & northern Australia

Temperate Grasslands (Plains & Prairies) Covered by a mix of grasses & the world’s most fertile soils – Warm to hot summers & cold winters – Seasonal precipitation Most have been converted into agricultural fields, because things grow really well here.

Desert Extremely DRY – Extreme temperature changes – Soils are rich in minerals, but poor in organic material – Plants are well adapted for storing water – Found in Africa, Asia, the Middle East, United States, Mexico, South America, & Australia

Temperate Forest Contain a mixture of deciduous (trees that lose their leaves in fall) & coniferous (needle-shaped leaves) trees – Year round precipitation – Found within the eastern United States, southeastern Canada, most of Europe, parts of Japan, China & Australia

Soil rich in humus: material formed from decaying leaves and other organic matter

Tundra The ground is covered in permafrost with small, stunted plants. – Cold temperatures – Short growing season – Low precipitation – Humus-poor soil – Found in northern North America, Asia, and Europe Permafrost – a layer of permanently frozen subsoil

Boreal Forest (Taiga) Dense evergreen forest of coniferous trees – Winters are bitterly cold; summers are mild & long enough to let the ground thaw – Moderate precipitation, high humidity – Nutrient-poor soils – Located in North America, Asia, & northern Europe

Mount St. Helens Active volcano in Washington Erupted in 1980, all life destroyed What happens after that?

Ecological Succession A series of predictable changes that occur in a community over time Slow changes occur after a sudden natural disaster, like fires or volcanoes, but can also occur after human activity, like the clearing of a forest.

Ecological Succession Not about loss or destruction, but the evolution of a new community

Primary Succession Occurs on surfaces where no soil exists (after a volcanic eruption or after a glacier retreats) The first species to populate the area is the pioneer species. Lichens are usually pioneer species. Why?

Secondary Succession Occurs after a disturbance that destroys a community without destroying the soil (fire, disease, clearing of a forest)

Succession in a Marine Ecosystem – “Whale Fall” Occurs in 3 stages

Marine Succession – Stage 1 Begins when a whale dies & sinks to the ocean floor Attracts scavengers & decomposers, which eat the soft tissue of the whale

Marine Succession – Stage 2 After 1 year, most of the soft tissue has been eaten. Decomposition of the body enriches the sediment with nutrients, which attracts more marine life.

Marine Succession – Stage 3 Begins when only the skeleton remains Bacteria decompose the oils inside the bones. The bacteria can support a community of marine life.

Nutrients are the elements required for life. Carbon, oxygen, & hydrogen make up ~95% of the mass of all living things, but they are not the only elements required for life. – Cells also need nitrogen, phosphorous, potassium, etc. The elements that make up your body are billions of years old!

Biogeochemical Cycles Energy is transferred in one direction. Matter is cycled through the ecosystem in the biogeochemical cycles.

The Water Cycle How water moves through the air, land, & organisms – Evaporation: water  vapor from surface of bodies of water – Transpiration: water  vapor from plants – Condensation: vapor  water in clouds

The Carbon Cycle Carbon dioxide (CO 2 ) cycles through the ecosystem through air, water, land, and organisms.

Carbon enters the atmosphere through fossil fuel emissions & animal respiration. Photosynthesis takes up CO 2 from the atmosphere.

The Nitrogen Cycle Nitrogen (N) cycles through the atmosphere, organisms, and soil.

Nitrogen Fixation Nitrogen Fixation: bacteria take nitrogen (N 2 ) from the atmosphere and change it into a form that plants can take up from the soil called ammonium (NH 4 ).

Nitrogen Fixation Nitrification: ammonium not taken up by plants are converted to nitrates & nitrites by bacteria, which other plants can take up Denitrification: bacteria can turn the ammonium back to atmospheric nitrogen

The Nitrogen Cycle Consumers eat & take in nitrogen in order to make proteins.

The Phosphorous Cycle It does not enter the atmosphere, but rather is cycled through the soil, oceans, and organisms through consumption and decomposition

Nutrient Limitations An ecosystem needs a particular amount of each nutrient to thrive. A single nutrient can limit its success. An excess of a particular nutrient can cause over production of algae & plant growth (red tide).

Human Effects on Biogeochemical Cycles Carbon: burning fossil fuels releases previously isolated carbon back to the atmosphere Nitrogen & Phosphorus: we add fertilizers to assist crop growth & much of it gets washed away into rivers, lakes & oceans