Ecology. The study of organisms and their interaction with the environment

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1 Ecology The study of organisms and their interaction with the environment

2 Ecology Biosphere broadest, most inclusive level of organization - deepest part of the ocean to 6 miles above the earth - all organisms are found within the biosphere The biosphere is divided into biomes.

3 The Biosphere- includes all life forms of all sizes in all habitats. The biosphere is a thin layer at Earth s surface that extends from about 9km above the Earth s surface down to the bottom of the ocean. Observe a visual model of Earth's spheres.

4 Ecosystems found within the biosphere all organisms and non-living environment - biotic factors living components of the environment - abiotic factors physical and chemical characteristics of the environment interdependence/interconnectedness disturbance affects all organisms organisms alter their environment and are influenced by the environment

5 Ecosystems

6 Food webs Predator an organism that captures and consumes another organism (plants too poison spines) Prey an organism that is caught and devoured Natural Selection favors adaptations that improve predation and improve avoidance for prey

7 Food Web Relationships Producers autotrophs; base of any food chain Gross primary productivity rate at which producers capture energy Producers add biomass by making more organic material The rate at which biomass accumulates is the net primary productivity. Only energy stored as biomass is available to other organisms

8 Food Webs & Chains Food chain a single pathway of feeding relationships among organisms in an ecosystem that results in energy transfer Food web interrelated food chains in an ecosystem showing all the feeding relationships among the organisms

9 Food Chains

10 Food Webs

11 Trophic Diagrams A trophic level indicates the organisms position in the sequence of energy transfers Producers are the first trophic level in an ecosystem Consumers heterotrophs Herbivores eat producers (plants) second trophic level Carnivores eat other consumers Omnivores eat both producers and consumers Detritivores feed on dead organisms, leaves, wastes Decomposers decay dead organisms

12 Trophic Diagrams

13 Energy Transfer in Food Webs The energy transfer between trophic levels can vary from 1% to 20 %. This means the top trophic level will always be smaller than the one below it.

14 Water Cycle

15 Nitrogen Cycle

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17 Carbon Cycle

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19 Niches Niche a species way of life or the role it plays in its environment; a range of conditions a species can tolerate; interactions with its environment Fundamental Niche the range of conditions that a species can potentially tolerate and the range of resources it can potentially use. Realized Niche of a species is the range of resources a species actually uses. Generalists can live just about anywhere Ex: cockroach or opposum feeds on almost anything Specialists only live in a small range of niches Ex: koala of Australia feeds only on leaves from the Eucalyptus tree

20 Niches A niche is different than a habitat. A habitat is an area where an organism lives while a niche is its role or position in a habitat.

21 Ecology Tolerance Curve the range of conditions in which an organism can survive Acclimation the process of adjusting an organisms tolerance Conformers change as their external conditions change; ectotherms (Can NOT regulate its internal environment The body temperature is regulated by the environment.) Regulators use energy to control their internal conditions; endotherms -generates their own body heat. Dormancy a state of reduced activity during periods of unfavorable environmental conditions Resources the energy and materials a species needs to survive

22 Competition Competition: the use of the same limited resources by 2 or more species occurs when fundamental niches overlap Competitive exclusion occurs when 1 species is eliminated from a community because of competition for resources One species uses the resources more efficiently and has an advantage that eliminates the other species Resource partitioning each species only use part of the available resources

23 Resource Partitioning an adaptation that enables species to use different resources when they coexist in an area. Ex: Darwin's finches. (beaks) reduces competition. Five species of warblers live in spruce and fir trees and feed on insects. Each individual species forage for insects only in a particular section of the tree. Results- Competition among the species is reduced.

24 Organism Relationships Parasitism a relationship where one organism lives in/on/off another causing the host organism harm Ectoparasites external parasites Endoparasites internal parasites Ectoparasite Endoparasite

25 Organism Relationships Mutualism a relationship between two organisms where both organisms will benefit Example: pollinators and plants Commensalism a relationship between two organisms where one benefits and the other is not affected

26 Succession Succession the gradual, sequential re-growth of species in an area Primary development of a community in an area that has not supported life pioneer species Slow lack of minerals for growth Secondary sequential replacement of species that follows disruption of an existing community Soil is left intact, easier regrowth

27 Succession

28 Biomes Tropical Rain Forest Tropical Dry Forest Tropical Grassland/Savanna/Shrubland Desert Temperate Grassland Temperate Woodland & Shrubland Temperate Forest Northwestern Coniferous Forest Boreal Forest Tundra

29 Aquatic Ecosystems

30 Aquatic Ecosystems

31 Populations in an Ecosystem Community (Biological Community) all interacting organisms living in an area Population all the members of a species that live in one place at one time Population size number of individuals (usually estimated) Population density number of organisms per area Dispersion spatial distribution of the organisms 3 patterns of dispersion: clumped/even/random (can depend upon scale at which they are looked at)

32 Population Dispersion Patterns

33 Changes in Populations All populations change over time birth rate number of births in a given period of time mortality/death rate number of deaths in a given period of time life expectancy how long an animal lives Age structure distribution of individuals among different ages in a population Growth rate the amount a populations size changes in a given time 4 processes contribute to growth rate 1. Immigration movement of individuals into a population 2. Emmigration - movement of individuals out of a population 3. Birth 4. Death Growth Rate = Birth Rate Death Rate Carrying capacity the number of individuals the environment can support over a long period of time

34 Changes in Populations Limiting Factors restrains the growth of a population Limiting factors that control population size: 1. Density independent factors natural disasters, weather reduce the size of the population by the same proportion 2. Density dependent factors resources; triggered by increasing population density

35 Ecosystem Diversity The number of species an ecosystem contains is known as the species richness (simple count) Species diversity number of species in a community compared to the abundance of each species (number of each)

36 Ecosystem Diversity Closer to the equator the greater the species richness. Larger area = more species = more habitats Stability community s resistance to change function of species richness