Introduction to Ecology

Transcription

1 Introduction to Ecology

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3 Ecology The study of all components (abiotic and biotic) within a defined area. Basic organization: Biosphere Biomes Ecosystems Communities Populations Individuals

4 Scales of Ecological Organization

5 Of which level is this an example?

6 6 major terrestrial biomes TRF Desert Tundra Deciduous Forest Coniferous Forest Grasslands

7 Brain storm! What do you think the 3 main traits that help distinguish one biome from another?

8 Temperature Water (precipitation) Soil

9 Aquatic Biomes Major distinction is whether water is fresh or salt Estuaries: any where freshwater meets saltwater.

10 Marine Zones A)Intertidal/Neretic highly photic has contact with coast B) Open See/Oceanic photic but no contact with the coast C) Open Sea/Pelagic - non-photic no contact with land D) Deep sea/benthic - non-photic, cold temps and high pressure

11 Marine Zones are based on Depth Light Pressure what 2 main traits? Temperature Contact with coast

12 Which of the marine only sub-divisions will have the most life? Why?

13 Energy What governs the type, abundance and relationship between living and non-living things? The available energy! Therefore we can label biotic items in each ecosystem by their energy needs. Trophic = energy!

14 Trophic Levels Primary producers~ the trophic level that supports all others; autotrophs Primary consumers~ herbivores Secondary consumer-carnivores Tertiary consumers~ omnivores

15 Notice arrow direction!

16 Clean up crew! Detritivores- (Detritus feeders) aka scavengers-ex: Larger will be regulated on energy pyramid (as secondary consumer) because of size. Decomposers- EX: Smaller-does not get regulated on energy pyramid because of size. BOTH heterotrophs that feed on nonliving organic matter..

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18 Relationships (Community) Trophic structure / levels~ feeding relationships in an ecosystem as trophic means nourishment. Food chain~ trophic level food pathway, linear Food Web- many food chains

19 Energy Flow Ecological efficiency: % of E transferred from one trophic level to the next (10% gets through, called the 10% Law)- multiplicative loss per level We have 3 diagrams to illustrate efficiency and numbers of organisms/energy:

20 Pyramid of Energy/productivity: shows the amount of retained and available energy per trophic level. (Measured in Joules J)

21 Pyramid of Biomass: shows actual weight of what each trophic level contains

22 Pyramid of Numbers: Shows the actual number of each type of organism on each trophic level

23 Complete the final concept map on your own, check your answers with the key AFTER it is completed

24 Biotic potential What is biotic potential? Don t all organisms want to maximize this? If they DID, what would their growth look like if we graphed # of animals over time? So, why DOESN T it look like that for most animals?

25 Population Growth Models Exponential model idealized Called r populations (J-curve) Logistic model realized Called K populations (S-curve) Which one happens most often? Why?

26 Strategies to increase biotic potential r-selected (opportunistic) Short maturation & lifespan Many (smaller) offspring No/little parental care High death rate EX:? K-selected (equilibrial) Long maturation & lifespan Few (larger)offspring; Extensive parental care Low death rate EX:?

27 Population limiting factors- Environmental resistance! Density-dependent factors: limited food water, shelter predation disease Density-independent factors weather/climate These factors lead to K* (*K=The max number of individuals an area can sustain/carrying capacity) Biotic potential vs Environmental resistance! (All life must deal with this) Leads to adaptation

28 More ways to increase success is to partake in Symbiosis. (2 unrelated organisms living close together.) Mutualism +/+ both species benefit Commensalism +/o one species benefits, the other is unaffected Parasitism +/- one species benefits, the other is harmed Neutralism o/o Neither organism benefits or is hurt

29 Mutualism

30 Commensalism

31 Parasitism

32 Neutralism

33 Predator/ Prey relationshipsspecial competition

34 Predator & Prey Evolutionary Arms Race, adaptation at its best! Both predator and prey develop strategies to live! (behaviorally and physically) Camouflage, weaponry, warnings, shells, stealth, ambush! (Active versus passive defense and/or killing strategies) Natural Selection will select for beneficial traits which lead to greater fitness

35 Types of competition: Intra-specific competition: occurs among organisms belonging to the same species. Inter-specific competition: occurs between organisms from different species (predator-prey)

36 Competition reduction Resource partitioning~ parapatric species consume slightly different foods or use other resources in slightly different ways (Develop niches) Character displacement~ sympatric species tend to diverge in those characteristics that overlap Ex: Anolis lizard sp. perching sites in the Dominican Republic Ex: Darwin s finch beak size on the Galapagos Islands

37 5 Types of specific coloration adaptations: Aposematic coloration Stay away color Batesian mimicry copy cat, only 1 bad Mullerian mimicry 2 poisonous resemble one another Camouflage blend in Disruptive coloring obscures size or shape of organisms body.

38 Aposematic coloring poison dart frog

39 Batesian mimicry

40 Mullerian mimicry

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44 So all of these adaptations lead to the potential increase in what?

45 Demography: factors that affect growth and decline of populations Birth Rate - # offspring produced (natality) Death rate number of organisms that die (mortatlity) Age structure relative number of individuals of each age

46 Survivorship curve plot of numbers that still alive at each age Type 1 Death more old age (EX?) Type 2 Death equally likely at all ages (EX?) Type 3 Death more likely at young age (EX?) Where would you place k selected and r selected populations?

47 Chemical Cycling Biogeochemical cycles: the various nutrient circuits, which involve both abiotic and biotic components of an ecosystem Water Carbon Nitrogen (Phosphorous)

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51 Nitrogen Cycle Nitrogen enters the atmosphere, in gaseous form N 2. It has to be transformed into a usable form for organisms to use. Nitrogen fixing bacteria convert N 2 into NH 4 in a process called nitrogen fixation. NH 4 is also produced by decomposers when breaking down organic matter in a process called ammonification. Different bacteria take NH4 and covert it into nitrite (NO 2- ) and nitrate (NO 3- ) in a process called nitrification. (This allows producers to use the nitrogen now, assimilation) Denitrifying bacteria convert nitrate (NO3-) back to N 2 for release back into the atmosphere.

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53 Succession Video

54 Big Changes in the system Primary succession- going from nothing (no soil)to pioneering community to climax community. Why would there be nothing??? Melting glaciers Volcanic eruptions Landslides Strip mines

55 Secondary Succession - Re-establish an ecosystem after a disturbance What could be a possible disturbance? Flood Fire

56 Geographic dispersion of a population shows how individuals in a population are spaced. Population dispersion refers to how a population is spread in an area. (Density) Clumped dispersion Uniform dispersion Random dispersion

57 There are three types of dispersion. clumped uniform random

58 Estimating number of individuals in a population Why would we want to know how large a population is?

59 So HOW do we determine how large a population is? 3 major ways: 1) Random Sampling 2) Point Intercept 3) Mark & Recapture (Lincoln index)

60 Random Sampling Take the area you are analyzing. Divide it into equal quadrants. Randomly select a specific number of subdivided quadrants, count all organisms in those areas. Add up all organisms counted, divide by # of quadrants than X by total quadrants. 8/4=2 X16=32 Actual = 26 PROBLEMS?

61 Point Intercept Draw a line 10 meters out Count every organism that falls along the line. Total numbers of each species and multiply this number by total square area counting. EX: PROBLEMS?

62 Capture mark-recapture (Lincoln-Petersen index) In a given area, capture a specific number of organisms, mark them and release them back into the wild Over a set amount of time, recapture a preset number of organisms and keep track of how many have already been captured. (They have marks) Use math to estimate total population in an area. Problems?

63 Fishing with Electricity seconds