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13.1 Ecologists Study Relationships 13.1 Ecologists Study Relationships Ecology - study of the interactions between living things and their surroundings. 13.1 Ecologists Study Relationships Levels of Organization • Biosphere • Ecosystem • Community • Population • Organism 13.1 Ecologists Study Relationships Biosphere • The portion of earth that supports life • Extends from the lower atmosphere to the bottom of oceans • Supports diverse array of organisms and wide range of climates 13.1 Ecologists Study Relationships • An ecosystem/biome - all of the living and nonliving things in a given area (climate, soil, water, rocks). Ecosystem Ecosystem Community Community Population Population Organism Organism 13.1 Ecologists Study Relationships Earth has six major biomes. 13.1 Ecologists Study Relationships Community • All the populations of different species that live in the same place at the same time. • Example – Forest community Flowers, bushes, trees, snakes, frogs, birds, squirrels, deer, etc… 13.1 Ecologists Study Relationships Population • A group of organisms, of one species, which interbreed and live in the same place at the same time. • Example – Population of bullfrogs in Jackson Bog 13.1 Ecologists Study Relationships • An organism - individual living thing, ex: alligator. Organism Organism 13.1 Ecologists 13.2 Biotic and AbioticStudy FactorsRelationships KEY CONCEPT Every ecosystem includes both living and nonliving factors. 13.1 Ecologists 13.2 Biotic and AbioticStudy FactorsRelationships • Abiotic factors are nonliving things. – moisture – temperature – wind – sunlight – Soil • Not constant (always changing) sunlight moisture 13.1 Ecologists 13.2 Biotic and AbioticStudy FactorsRelationships Biotic Factors • Living components of the environment 13.1 Ecologists 13.2 Biotic and AbioticStudy FactorsRelationships • A keystone species is a species that has an unusually large effect on its ecosystem. keystone 16.3 13.2 Biotic Quality and AbioticStudy FactorsRelationships 13.1Water Ecologists • Indicator species provide a sign of an ecosystem’s health. – amphibians – top predators 13.1 Ecologists Study Relationships 13.3 Energy in Ecosystems Producers provide energy for other organisms in an ecosystem. • autotrophs - make their own food. 13.1 Ecologists Study Relationships 13.3 Energy in Ecosystems Almost all producers obtain energy from sunlight. • Photosynthesis • Chemosynthesis – produce energy from chemicals carbon dioxide + water + hydrogen sulfide + oxygen sugar + sulfuric acid 13.1 Ecologists Study Relationships 13.3 Energy in Ecosystems Measuring productivity • Gross primary productivity – rate at which producers capture E • Biomass – organic material in an ecosystem – Only E stored as biomass is available to other organisms in the ecosystem 13.1 Ecologists Study Relationships 13.3 Energy in Ecosystems Consumers are organisms that get their energy by eating other living or once-living resources. • heterotrophs 13.1 Ecologists Study Relationships 13.3 Energy in Ecosystems • Herbivores – eat producers • Carnivores – eat other consumers • Omnivores – eat both producers and consumers • Detritivores – feed on the “garbage” of an ecosystem 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs A food chain is a model that shows a single chain of consumers within an ecosystem. • arrows point in the direction that energy flows GRAMA GRASS DESERT COTTONTAIL HARRIS’S HAWK 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs A food web - interrelated food chains in an ecosystem 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Energy Flow moves from producers to consumers Trophic level – indicates the organism’s position in the sequence of energy transfers • Producers – 1st trophic level • Herbivores – 2nd trophic level • Predators of herbivores – 3rd trophic level 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Quantity of Energy Transfers 10% of the total E consumed in one trophic level is incorporated into the organism in the next level • E is used to maintain body T, to move, etc. • E is lost when organisms escape being eaten – decomposer return their E to the lower trophic levels • E is lost in parts of the organism that can not be broken down by the predator – bones, teeth, hair 13.1 Ecologists Study Relationships 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs An energy pyramid shows the distribution of energy among trophic levels. •Higher trophic levels contain less energy • support fewer individuals energy lost energy transferred 16.3 13.4 Food Chains Qualityand Study Food Webs 13.1Water Ecologists Relationships Biomagnification - accumulation of toxins in the food chain. • Pollutants move up the food chain. – predators eat contaminated prey • Top consumers (humans) are most affected. • DDT- Birds of prey 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Species Interactions Predation • Predator – captures, kills, and consumes prey – Influences where and how species live by determining their relationship in the food web – Regulates population size Natural selection favors adaptations that improve the efficiency of predators at finding, capturing, and consuming prey Natural selection favors adaptations for prey to avoid, escape, or otherwise ward off predators 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Natural selection of plants has favored adaptations that protect them from being eaten • Thorns, sticky hairs, tough leaves • Chemical defenses (secondary compounds) – Strychnine, nicotine, poison ivy – May also have medicinal uses – codeine, morphine 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Parasitism – one individual is harmed (host) while the other benefits (parasite) • Does not usually result in the immediate death of the host 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Ectoparasite – external parasites – do not enter hosts body • Ticks, fleas, lice, leeches, mosquitoes Endoparasite – internal parasite – live inside host • Disease causing bacteria, protists, tapeworm Affect the health and reproduction of the host Stimulates evolution of defenses in hosts • Tough skin & chemically defended openings – eyes-tears – mouth-saliva – nose-mucus 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Natural selection favors adaptations that allow a parasite to efficiently attack host • Specialized anatomically – Mouth parts • and Physiologically – Body chemistry to survive different environments etc. 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Competition • The use of a limited resource by 2 or more species • Types – Intraspecific- competition between organisms of the same species – Interspecific- competition between 2 or more different species of organisms 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Competitive Exclusion • one species is eliminated from a community • Natural selection favors differences between potential competitors – character displacement 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Resource Partitioning • Organisms “divide” resources • Adaptations allow for use of resources in different ways or at different times • Examples – Diurnal vs. Nocturnal 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Mutualism Cooperative relationship in which both species benefit • Some relationships are so close that neither species can survive without the other • Ex: pollination 13.1 Ecologists Relationships 13.4 Food Chains and Study Food Webs Commensalism • Interaction in which one species benefits and the other is not affected 13.1 Ecologists 14.1 Habitat and NicheStudy Relationships Niche -Role of a species in its environment (Job) Types: – Fundamental- ideal; absence of competition – Realized- natural; competition and other constraints 13.1 Ecologists 14.1 Habitat and NicheStudy Relationships • Generalists are consumers that have a varying diet. • Specialists are consumers that primarily eat one specific organism or a very small number of organisms. 13.1 Ecologists 14.1 Habitat and NicheStudy Relationships Generalist vs. • Broad niche • Tolerate variety of resources and conditions • Example – raccoons Specialist • Narrow niche • Very specific adaptations • Example – Koalas 13.1 Ecologists 14.1 Habitat and NicheStudy Relationships A habitat is all aspects of the area in which an organism lives. – biotic factors – abiotic factors
