1 Interactions: Environments and Organisms Chapter 5

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1 Interactions: Environments and Organisms Chapter 5 Slide 2 2 Ecological Concepts __________ - Study of ways organisms interact with each other and with their non- living surroundings. __________ - Study of ways organisms interact with each other and with their non- living surroundings. __________ - Everything that affects an organism during its lifetime. __________ - Everything that affects an organism during its lifetime. Biotic - ___________________ Abiotic - ______________________ Slide 3 3 Levels of Organization in Ecology Slide 4 4 Ecological Concepts ____________ - Any factor whose shortage or absence restricts species success. ____________ - Any factor whose shortage or absence restricts species success. Range of Tolerance - Range of conditions an organism can survive in. Temperature pH DO Slide 5 5 Habitat and Niche _______ - Space an organism inhabits; defined by biological requirements of each particular organism. _______ - Space an organism inhabits; defined by biological requirements of each particular organism. Usually highlighted by prominent physical or biological features. Niche - __________________________________ Niche - __________________________________ Includes all ways an organism affects organisms with which it interacts as well as how it modifies its physical surroundings. Fig. 5.3 Fig. 5.3 Slide 6 6 Ecological Niche Slide 7 7 Genes Population and Species ________ - Distinct pieces of DNA that determine the characteristics an organism displays. ________ - Distinct pieces of DNA that determine the characteristics an organism displays. Population - ____________________________________ ____________________________________ Population - ____________________________________ ____________________________________ Contains more kinds of genes than any single individual within the population. Slide 8 8 Genes Population and Species Species - ____________________________________ ____________________________________ ____________________________________ ____________________________________ Species - ____________________________________ ____________________________________ ____________________________________ ____________________________________ Working definition that only applies to organisms that sexually reproduce. Some species are easy to recognize, while others are more difficult. Slide 9 9 ______________ - Process that determines which individuals within a species will reproduce and pass their genes to the next generation. ______________ - Process that determines which individuals within a species will reproduce and pass their genes to the next generation. Conditions: Conditions: Individuals within a species show genetically determined variation. Organisms within a species typically produce huge numbers of offspring, most of which die. Natural Selection Slide 10 10 Natural Selection Conditions Excess number of individuals results in a shortage of specific resources. Due to individual variation, some individuals have a greater chance of obtaining needed resources and thus have a greater likelihood of survival and reproduction. As time passes, percentage of individuals showing favorable variations will increase while percentage showing unfavorable variations will decrease. Slide 11 11 Evolutionary Patterns __________ - A change in the kinds of organisms that exist and in their characteristics. __________ - A change in the kinds of organisms that exist and in their characteristics. Ex. Building tolerance to pesticides. Speciation - ____________________________________ ____________________________________ Speciation - ____________________________________ ____________________________________ Thought to occur as a result of a species dividing into two reproductively isolated subpopulations. Slide 12 12 Evolutionary Patterns Extinction - Loss of entire species. Extinction - Loss of entire species. Of estimated 500 million species believed to have ever existed on earth, 98-99% have gone extinct. __________ - Two or more species can reciprocally influence the evolutionary direction of the other. __________ - Two or more species can reciprocally influence the evolutionary direction of the other. Grazing animals and grass species. Slide 13 13 Kinds of Organism Interactions Predation - _____________________________________ _____________________________________ Predation - _____________________________________ _____________________________________ Prey adaptation is manifested in a higher reproduction rate. Fig. 5.7 Slide 14 14 Kinds of Organism Interactions Prey species benefits by eliminating non-adaptive genes from the gene pool. Poorly adapted predators are less likely to obtain food and thus pass on non-adaptive genes. Slide 15 15 Competition Competition - Two organisms strive to obtain the same limited resource, and both are harmed to some extinct. Competition - Two organisms strive to obtain the same limited resource, and both are harmed to some extinct. ___________ - Members of same species competing for resources. (Mice for Cheese) ___________- Members of different species competing for resources. (Fox & Hawk for Mice) The more similar the competing species, the more intense the competition. The more similar the competing species, the more intense the competition. Fig. 5.8 Fig. 5.8 Slide 16 16 Competition ______________________ - No two species can occupy the same ecological niche in the same place at the same time. ______________________ - No two species can occupy the same ecological niche in the same place at the same time. Less fit species must evolve into a slightly different niche. Slide 17 17 Symbiotic Relationships ___________ - Close, physical relationship between two different species. At least one species derives benefit from the interaction. ___________ - Close, physical relationship between two different species. At least one species derives benefit from the interaction. Parasitism - ______________________________________ ______________________________________ ______________________________________ Ectoparasites - Live on hosts surface. Fleas Endoparasites - Live inside host. Tapeworms Slide 18 18 Symbiotic Relationships Commensalism - One organism benefits while the other is not affected. Commensalism - One organism benefits while the other is not affected. Remoras and Sharks ___________ - Both species benefit. Obligatory in many cases as neither can exist without the other. ___________ - Both species benefit. Obligatory in many cases as neither can exist without the other. Mycorrhizae Slide 19 19 Community and Ecosystem Interactions Community - Assemblage of all interacting species of organisms in an area. Community - Assemblage of all interacting species of organisms in an area. __________ - Defined space in which interactions take place between a community, with all its complex interrelationships, and the physical environment. __________ - Defined space in which interactions take place between a community, with all its complex interrelationships, and the physical environment. Slide 20 20 Major Roles of Organisms in Ecosystems Producers - Organisms able to use sources of energy to make complex organic molecules from simple inorganic molecules in the environment. Producers - Organisms able to use sources of energy to make complex organic molecules from simple inorganic molecules in the environment. Ex. Grasses, Trees, Moss, Ferns Slide 21 21 Roles of Organisms __________ - Consume organic matter to provide themselves with energy and organic matter necessary for growth and survival. __________ - Consume organic matter to provide themselves with energy and organic matter necessary for growth and survival. Primary Consumers Herbivores (plants) Secondary Consumers Carnivores (animals) Omnivores (plants and animals) Scavengers (dead animals) Slide 22 22 Roles of Organisms _______________ _______________ Digest organic molecules in detritus into simpler organic compounds, and absorb soluble nutrients. (Bacteria and Fungi) Use non-living organic matter as source of energy. Keystone Species Keystone Species Play critical role in maintenance of specific ecosystems. Bison in American Tall Grass Prairie Slide 23 23 Energy Flow Through Ecosystems Each step in the flow of energy through an ecosystem is known as a ___________. Each step in the flow of energy through an ecosystem is known as a ___________. As energy moves from one trophic level to the next, most of the useful energy (90%) is lost as heat (2 nd Law of Thermodynamics). Because energy is difficult to track, biomass (weight of living material) is often used as a proxy. Slide 24 24 Energy Flow Through an Ecosystem Slide 25 25 Food Chains and Food Webs _________ - Passage of energy from one trophic level to the next due to one organism consuming another. _________ - Passage of energy from one trophic level to the next due to one organism consuming another. Some chains rely on detritus. _________ - Series of multiple, overlapping food chains. _________ - Series of multiple, overlapping food chains. A single predator can have multiple prey species at the same time. Fig. 5.15 Slide 26 26 Food Chain Slide 27 27 Nutrient Cycles in Ecosystems Organisms are composed of molecules and atoms that are cycled between living and non-living portions of an ecosystem. Organisms are composed of molecules and atoms that are cycled between living and non-living portions of an ecosystem. Biogeochemical Cycles - another name for nutrient cycles. Slide 28 28 Carbon Cycle Carbon and oxygen combine to form carbon dioxide. Carbon and oxygen combine to form carbon dioxide. Plants use carbon dioxide during photosynthesis to produce sugars. Plants use sugars for plant growth. Herbivores eat plants, and incorporate molecules into their structure. Respiration breaks down sugars releasing CO 2 and water back into the atmosphere. Slide 29 29 Carbon Cyc