1. Chapter 33, pg. 678-693

2. What does the discipline of ecology study? What levels of organization are studied in ecology? What are 2 opposing models to explain community composition? What is ecological succession? Explain.

3. Ecology: study of relationships among living organisms and the interactions they have with environment

4. 1. Individual: how they are adapted to their environment 2. Population: individuals of a same species that share the same geographical location at the same time How the size changes over time 3. Community: group of interacting populations occupying the same geographic area at the same time Effects of extrinsic and intrinsic factors on these populations

5. 4. Ecosystem: biological community and all abiotic factors that affect it 5. Biome: large group of ecosystems that share the same climate and have similar types of communities 6. Bioshpere: all biomes on Earth Air, land, and water

7. Composition: the populations within the community Diversity: both the number of different populations and the relative abundance of individuals The greater the diversity, the greater the number and the more even the populations!

8. Question: Why do populations assemble together in the same place at the same time? Interactive Model Community is highest level of organization (cell, tissue, organism, population, community) Populations dependent on biotic interactions (ex. food chain) Predicts that composition in a particular place will always be the same

9. Individualistic Model Hypothesizes that populations assemble according to species’ tolerance for abiotic factors Less diversity up north due to conditions Predicts that compositions are not constant; boundaries between communities are not distinct

10. Ecological Succession: change in community composition over time Result of changing abiotic/biotic factors There are 2 types of ecological succession: Primary Succession and Secondary Succession

11. establishing a community in an area of exposed rock without topsoil Natural events (retreating glaciers) can scrape rock bare OR new rock could form after a volcanic eruption Wind and rain carry spores of organisms, like lichens, to these areas Lichens are a combination of fungus and algae Obtain nutrients from rocks by secreting chemicals that break down the rock

13. Each stage of primary succession is gradual and introduces different populations of micro- organisms, plants and animals that will compete for nutrient, moisture, and sunlight As organisms decompose, they contribute more organic matter to the soil layer Eventually, seeds of trees will germinate

14. 1 st trees usually requires lots of light (ex. deciduous trees of boreal forests) The shade will change abiotic conditions as soil becomes cooler and more moist Only shade tolerant plants will grow As more niches are created, there is be greater diversity in organisms  creating more complex food webs

16. Orderly and predictable change that takes place after a community of organisms has been removed but the soil remained intact result of a disturbance to an area that already has soil and was once the home of living organisms

17. Occurs much faster than primary succession because soil and nutrients already exist Often depends on the recovery of existing plants, such as trees, and on species that can rapidly reproduce in new conditions of increased sunlight and open areas Pioneer species often 1 st to grow back Succession’s end point can’t be predicted change at different rates; process can be slow

18. 1. Climax-Pattern Model: particular areas will always result in same type of community (a climax community) Based on observation that climate determines growth Being modified – accept that exact composition of community may not be the same 2. Facilitation Model: each stage is necessary for the next to occur No shrubs until the grasses have created better soil

19. 3. Inhibition Model: colonists inhibit new growth until they are damaged or die 4. Tolerance Model: different types of plants can colonize at the same time Stages reflect amount of time needed for species to mature

20. Population size depends on what factors? What are 2 patterns of population growth? What is the purpose of a survivorship curve? What trends are seen in the growth of the human population?

21. Population Density: number of organisms per unit area or volume Usually expressed as “number of population” per “number of square unit” (metres, miles) Population (or Spatial) Distribution: pattern of dispersal (or spacing) of a population within an area 3 types of patterns: uniform, clumped (or grouped), and random

22. Limiting Factors: factors that determine whether an organism lives in a particular area Usually determined by abiotic/biotic factors Amount of resources, predators, temperature, etc. Ex. Trout will live in areas where the water is cool and highly oxygenated

23. Populations have a certain size, and the size can stay the same from year to year, increase, or decrease, according to a per capita rate of increase. This considers the size of the population, birth rate, and death rate. It does not include immigration and emigration! Example: A small town of 1000 people where 30 babies are born each year and 10 people die per year. (30-10) / 1000 = 0.02  2% per year

24. Biotic Potential: highest possible per capita rate of increase for a population Will be high or low depending on usual number of offspring per reproduction, chances of survival until age o reproduction, how often each individual reproduces, and age at which reproduction begins Exponential Growth: a J-shaped curves, can see how a population would explode if there were no limits (ex. insects) Lag phase: growth is small because population is small Exponential growth phase: growth accelerates, population exhibits biotic potential

25. Environmental Resistance typically stops exponential growth includes the environmental conditions (food supply, waste products, competition) that prevent a population from growing too large. growth will level off, creating a pattern of logistic growth.

26. Logistic Growth Model: Realistic model of population growth; S-shaped curve Occurs when population growth slows when approaching carrying capacity (the amount that the environment can support) Stops increasing when # of births immigration Lag phase: growth small because population small Exponential growth phase: growth accelerates due to biotic potential Deceleration phase: rate of growth slows Stable equilibrium phase: little, if any, growth because births and deaths about equal

28. Cohort: members of an original group born at the same time and are still alive after certain intervals of time 3 types of curves: Curve I – typical of humans; most individuals survive past midpoint and death occurs at the end of the life span Curve II – typical of hydras; survivorship decreases at a steady rate throughout life span Curve III – typical of oysters; most individuals die very young

30. Doubling Time: length of time needed for a population size to double Estimated about 53 years More Developed vs. Less Developed Countries MDC includes North America and Europe, countries where population growth is low and good standard of living LDC include Latin America, Africa, and Asia, countries where population growth is expanding and majority of people live in poverty

31. More Developed Countries... Doubled populations between 1850-1950 (decline in death rate, modern medicine, and improved socioeconomic conditions) Modest growth between 1950-1975 (decline in birth rate) Yearly growth now stabilized, some even declining Sequence of events known as demographic transition Less Developed Countries... Birth rate remained high after 1945 Demographic transition after 1965 (birth rate fell and decline in death rate slowed

32. Methods to reduce the increase in human populations... Establish/strength family planning programs; support from community leaders Use social progress to reduce desire for large families (education, increased status of women, social improvements) Delay onset of childbearing

33. Age Structure Diagrams: divide population into 3 groups – dependency, reproductive, and postreproductive Ex. LDCs have more women entering reproductive years than older women leaving them Zero Population Growth: no increase in the population size Replacement Reproduction: causes most countries to continue growing due to age structure of population If more young women enter reproductive years than older women leaving, growth will occur

35. What are 2 life history patterns? What types of organisms exhibit each? What density-independent factor affect population size? What affect does competition have on the composition of a community? How can predation affect the population densities of both predator and prey? What are some effective anti-predator defenses? What are the 3 types of symbiotic relationships? Explain.

37. There are 2 types of life history patterns: 1. Opportunistic Pattern: members are small in size, mature early, and have a short life span Produce small offspring and favour greater numbers over parental care Classic Ex.: insects, weeds

38. 2. Equilibrium Pattern: size remains constant at carrying capacity Those who can compete most likely to have large number of offspring Dedicate time/energy to their own growth and survival and their offspring Fairly large slow to mature, and have a fairly long lifespan Classic Ex.: whales, horses, etc.

39. REVIEW: In 33.2, we talked about some factors that limit exponential growth of population. These factors can be divided into 2 groups – density- independent and density-dependent factors! Density-Independent Factors: Any factor in the environment that does NOT depend on the # of members in a population per unit area Usually abiotic Include natural phenomena l – weather like flooding, extreme heat/cold, and hurricanes Typically regulates populations with opportunistic life patterns

40. Density-Dependent Factors: Any factor in the environment that depends on the number of members in a population per unit area Often biotic factors  predation, disease, parasites, and competition Typically regulates populations with equilibrium life patterns

42. Competition: when 2+ organisms try to use limited resources at the same time Competitive Exclusion Principle: no 2 species can occupy the same ecological niche at the same time if resources are limited Habitat: an area where an organism lives Niche: role or position that an organism has in its environment, including habitat and interactions How it meets its needs for food, shelter, and reproduction Could relate to living space, temperature, moisture, etc.

43. Resource Partitioning: decreases competition between the 2 species; even though similar species seem to occupy the sae niche, there are usually small differences When grown in a test tube, 2 different paramecia can survive if one feeds on bacteria on the bottom of the tube while the other feeds from bacteria at the top 1 tree  one bird species might eat insects on leave, while another eats insects on the bark

45. Predation: act of one organism (predator) consuming another (prey) Ladybugs eating aphids (beneficial insects) Parasitic ticks

46. Predator-Prey Population Dynamics: dynamic, not steady Predator-prey relationships experience cycles Predators overkill prey, resulting in predator decline Prey population overshoots carrying capacity then crashes, decreasing prey population

47. Antipredator Defenses: prey strategies to avoid predation Ex. releasing poisonous chemicals to prevent ingestion, camouflage, warning coloration Coevolution: occurs when 2 species adapt in response to one another Acacia trees evolved long thorns to prevent grazing, so giraffes evolved long, prehensile tongues

49. Mimicry: one species resembles another to possess an antipredator defense Can help predators hunt or prey avoid capture Batesian mimicry – when prey mimics another species with a successful antipredator defense Ex. flies that look like wasps Mullerian mimicry – when prey have the same defense Ex. stinging insects (bees, wasps, hornets) all have black and yellow bands

51. Symbiotic Relationships: symbiosis is the close relationship between 2+ species 3 types of relationships: parasitism, commensalism, and mutualism

52. Parasitism: where one organism (parasite) benefits while the other (host) is harmed Can be external (fleas, ticks) or internal (bacteria, tapeworms) Occurs in all kingdoms Host provides nourishment, and a place to live/reproduce

54. Commensalism: relationship where 1 organism benefits while the other is neither helped nor harmed Lichens grow on trees for better light access and do not harm the tree sea anemones provide a home for clownfish

56. Mutualism: relationship between 2+ organisms that live closely together and benefit from each other fungi provides a habitat for algae, which provide food butterflies feed on flower nectar while pollinating the flowers Cleaning Symbiosis: relationship where the individual being cleaned is a vertebrate and the cleaner is a crustacean/fish/bird