Presentation is loading. Please wait.

Presentation is loading. Please wait.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Living In Ecosystems Chapter 30 Copyright © McGraw-Hill Companies Permission.

Similar presentations


Presentation on theme: "Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Living In Ecosystems Chapter 30 Copyright © McGraw-Hill Companies Permission."— Presentation transcript:

1 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Living In Ecosystems Chapter 30 Copyright © McGraw-Hill Companies Permission required for reproduction or display

2 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Outline Population Growth Life History Adaptations Population Demography The Niche and Competition  Resource Partitioning Symbiotic Relationships Plant and Animal Defenses Predator-Prey Cycles Ecological Succession

3 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Growth Populations are composed of groups of individuals of the same species living together.  Critical Properties - Population Size - Population Density - Population Dispersion - Capacity for Growth

4 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Growth Exponential Growth Model  Assumes population growing without limits at its maximal rate. (r = biotic potential) dN/dt=r i N - N = Number of individuals in population - dN/dt = Rate of change in population size over time - r i = Intrinsic rate of increase

5 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Growth A population’s actual rate of increase is the difference between birth rate and death rate corrected for migration. Innate capacity for growth of any population is exponential.  Even when rate of increase remains constant, the actual increase in the number of individuals accelerates rapidly as the size of the population grows.

6 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Growth Carrying Capacity (K)  Number of individuals an area can indefinitely support. Logistic Growth Model  As population approaches its carrying capacity, its growth rate slows as resources become scarce. dN/dt = rN (K-N/K) - Sigmoid Growth Curve

7 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Two Models of Population Growth

8 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Life History Adaptations Exponential Model  Describes species with r-selected adaptations. - Favor high rate of increase Logistic Model  Describes species with k-selected adaptations. - Favor reproduction near carrying capacity.

9 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies

10 Influence of Population Density Density-Dependent Effects  Effects are independent of population size and act to regulate growth (weather). Density-Dependent Effects  Effects are dependent on size of population and act to regulate growth (resource competition). - Have increasing effect as population size increases.

11 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Demography Age Structure  Cohort - Group of individuals of same age. Each has a characteristic: - Fecundity Rate - Number of offspring produced during a standard time. - Mortality Rate - Number of individuals that die during a standard time.  Relative number of individuals in each cohort defines population’s age structure.

12 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Demography Sex Ratio  Proportion of males and females in a population. - Usually directly related to number of females in the population.

13 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Demography Survivorship Curves  Graphically express age distribution characteristics by plotting percentage of original population that survives to a given age. - Type I - Mortality rises in post- reproductive years. - Type II - Mortality constant throughout life. - Type III - Mortality low after establishment.

14 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Survivorship Curves Copyright © McGraw-Hill Companies Permission required for reproduction or display

15 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Population Demography Life Tables  Indicate chance of survival at any age. - Follow cohort from birth to death.

16 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies The Niche and Competition Niche - Biological role in community.  Fundamental - Theoretical role  Realized - Actual role Competition - Two or more organisms attempt to use same resource.  Interference - Fighting  Exploitative - Consuming shared resources  Interspecific - Different species  Intraspecific - Same species

17 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Barnacle Competition

18 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Competitive Exclusion Gause - No two species can coexist in the same niche indefinitely.  When two species coexist on long-term basis, their niches differ in one or more features. - Otherwise, one is eventually driven to extinction.

19 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Resource Partitioning Sympatric Species - Occupy same geographical area but avoid competition by utilizing different portions of the habitat.  Character Displacement - Differences arise between species due to natural selection. Allopatric Species - Do not occupy same geographical area, thus are not usually in competition.

20 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Symbiosis Symbiotic Relationship - Two or more species of organisms live together, and at least one gains benefit.  Commensalism - One species benefits while other neither benefits or is harmed.  Mutualism - Both species benefit.  Parasitism - One species benefits while the other is harmed.

21 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Commensalism Symbiotic relationship that benefits one species and neither hurts or helps the other.  Oxpeckers and Rhinos - No definite boundary between commensalism and mutualism. Copyright © McGraw-Hill Companies Permission required for reproduction or display

22 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Mutualism Symbiotic relationship among organisms in which both species benefit.  Ants and Aphids  Ants an Acacias Copyright © McGraw-Hill Companies Permission required for reproduction or display

23 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Parasitism Specialized form of symbiosis in which predator is much smaller than prey. Interaction is harmful to prey but beneficial to predators.  Ectoparasites - External parasites. - Parasitoids - Lay eggs on living hosts.  Endoparasites - Internal parasites.  Brood Parasitism - Lay eggs in nests of other species.

24 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Plant Defenses Predator-Prey Interactions  Morphological Defenses - Thorns, spines, plant hairs  Chemical Defenses - Secondary chemical compounds Evolution of herbivores avoiding plant defense allows access to a new resource without competition from other herbivores.

25 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Animal Defenses Feeding on plants rich in secondary compounds may have added benefit.  Blue Jays and Monarch Butterflies Defensive Coloration  Aposomatic Coloration - Advertise poisonous nature with bright coloration.  Cryptic Coloration - Camouflage Chemical Defenses

26 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Predator-Prey Cycles Predation is consumption of one organism by another.  Under simple laboratory conditions, predators often exterminate their prey, and then become extinct themselves when they run out of food. - If refuges are provided for the prey, a few individuals usually exist, and then repopulate after the predators die out.

27 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Predator-Prey Cycles Snowshoe Hares (Lepus americanus).  Food - Willows  Predators - Canada Lynx (Lynx canadensis)

28 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Mimicry Batesian Mimicry - Palatable individuals mimic distasteful or toxic individuals.  Mimics must be relatively rare. Mullerian Mimicry - Unrelated but protected (toxic) species come to resemble one another. Copyright © McGraw-Hill Companies Permission required for reproduction or display

29 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Ecological Succession Succession - Ecosystem change from simple to more complex plant communities.  Secondary Succession - Occurs in areas where an existing community has been disturbed.  Primary Succession - Occurs on bare rocks. - Climax Community

30 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Ecological Succession Three Critical Concepts of Succession  Tolerance  Facilitation  Inhibition

31 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Biodiversity Measure of number of different types of species in an area.  Crucial to ecosystem preservation. Biodiversity Promotion  Ecosystem Size - Larger ecosystems, usually have higher levels of biodiversity  Latitude - Length of growing season - Climatic stability

32 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Latitudinal Cline in Species Richness

33 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Island Biogeography Equilibrium Model  McArthur and Wilson proposed island species richness is a dynamic equilibrium between colonization and extinction. - Island size and distance from mainland play important roles.

34 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Equilibrium Model of Island Biogeography

35 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Review Population Growth Life History Adaptations Population Demography The Niche and Competition  Resource Partitioning Symbiotic Relationships Plant and Animal Defenses Predator-Prey Cycles Ecological Succession

36 Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display


Download ppt "Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Living In Ecosystems Chapter 30 Copyright © McGraw-Hill Companies Permission."

Similar presentations


Ads by Google