What Is Life? 8 Life Characteristics ______________________________________________________

Ecology The study of the interaction of living things with ______________________________________________________ From Greek “oikos” – a place to live “logos” - study

Energy pyramid On average only ______ of energy at one trophic level is available to the next

Biotic factors of an ecosystem Population All the members of the ________________ that inhabit a particular area Community All of the members of ___________________ Ecosystem ________________ and ________________ factors

Abiotic Factors ( components) Ex. Biotic Factors ( components) Ex.

Biosphere All of Earth’s __________________________ Lithosphere - Hydrosphere - Atmosphere -

Biome Characteristics Composed of __________________. Certain plant & animal _____________. Have specific __________ with similar plants and animal ________________.

Categories of Biomes Tundra Taiga Grasslands Deserts Deciduous Forests Tropical Rainforests Other Biomes Chaparral Savanna Tropical Deciduous Rain Forest

Biomes of the world

Soil nutrients Simple Food chain

Categories of Biotic Organisms Producer Consumer - in most ecosystems -phytoplankton (, ) - synthesis or synthesis 6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2

Decomposers -external digestion -mostly bacteria and fungi -feed on partially decomposed matter -e.g. crabs, termites, worms -e.g. vultures, crows, lobsters

Consumers -feed on producers or consumers -plant eaters -primary consumers -meat eaters -secondary (tertiary) consumers -eat both plants and animals

Food Chains all organisms feeding at a particular level

______________– a summary of the feeding relationships in a community

Trophic level – position in the ________________ –___________(lowest level) –____________– act as predators and prey –______ predators – have no predators

_____________________________________– one that has a dominant effect on community composition –reduce _______________among prey species –allow poorer competitors to persist Top predators __________always keystone predators –abundance –feeding patterns

Stability in Food Webs A community is stable if –it doesn’t change much in response to environmental changes, or –it returns to its previous state after a disturbance Early models suggested that larger food webs are unstable

Current view: more diverse food webs are more stable –more species = weaker interactions on average –species influenced by many weak interactions have more stable populations than species with few strong interactions –This is why elimination of species is dangerous! Field research suggests most interactions in nature are weak.

No predators Limited only by food Limited by predation Limited by competition and resources