Ecosystem Biosphere – entire part of the Earth where living exists. Soil, water, light, air. Ecosystem – interactions between living and non-living matter Community – group of interacting populations Population – individuals that belong to the same species

Ecosystems Interactions between living and non-living matter Cycles – carbon, water, nitrogen

Carbon Cycle

Water Cycle

Nitrogen Cycle

Community Producers, Consumers, Decomposers – food chains Niche – an organism’s position and function in the community. 10% Rule – only 10% of energy is transferred from one level to the next

Primary productivity NPP= GPP-R

Trophic interactions Dominant species – abundant, contributes the most biomass Keystone species – have strong influence on health of a community Ex. Sea otters eat sea urchins (eat kelp). When otter population drops? Ex. Wolves eat large herbivores like elk, deer, coyotes pg. 249 Invasive species – kudzu, dutch elm fungus, potato protist, small pox pg. 249

Models of interaction Bottom up Top down Pg. 250 Biodiversity is detemined by Climate Latitude Habitat elevation

Food Chain

Pyramid of Energy

Community Ecology Interspecific competition – competition between different species Resolved by: Competitive exclusion – Gause’s principle – one individual outcompetes the other and replaces them in the niche Resource partitioning – when different species can occupy a slightly different niche and live together

Resource partitioning

More ways to resolve competition Character displacement – a slight difference can change an organism’s niche and reduce competition. Ex. Bird beaks on the Galapagos Realized Niche vs. fundamental niche – fundamental niche is the one without competition, realized is one that the organism settles for. Ex. Barnacles

Fundamental and Realized Niches

Predation True predator – kills and eats its prey Parasite – living off of the host without killing the host Parasitoid – lays eggs in a host Herbivore – eats plants, granivores, grazers, browsers

Symbiosis Mutualism – both benefit Commensalism – one benefits, while the other is neither helped nor harmed Parasitism – host is harmed, parasite benefits

Coevolution Coevolution – the evolution one species in response to another. Secondary compounds – toxic chemicals that discourage herbivores. Camouflage – is any color, pattern, shape, behavior that enables an animal to blend in with surroundings. Aposematic coloration (warning coloration) – color of bees warns animals Mimicry Mullerian Mimicry – bees, wasps, yellow jackets Batesian mimicry – flies with yellow and black markings

Batesian Mimicry

Mullerian mimicry

Camouflage

Warning Coloration

Ecological Succession Ecological Succession – the change in composition over time. As succession progresses, the species and total biomass changes. The first species is a pioneer species. They are usually r-selected. Bacteria, fungus, protists As soil, light, water and pH change the community changes. K selected species replace r selected species. The final succession is the climax community.

Primary Succession Occurs when the substrate has never supported living things Rock and lava – lichen, fungus, bacteria, mosses, protists, then insects, then K selected species such as large trees and perennial shrubs Sand Dunes – grasses, low shrubs, oak, then maple

Secondary succession When communities rebound after a damaging event. Abandoned cropland – r selected grasses and shrubs, then pines, then oaks Lakes and ponds – submerged vegetation, then grasses and cattails, then a meadow, then forest.

Succession

Secondary Succession