Topic 5 review

1. Topic 5 review

2. Populations – 5.3 • 5.3.1: Outline how population size can be affected by natality, immigration, mortality and emigration • 5.3.2: Draw and label a graph showing the sigmoid (S-shaped) population growth curve • 5.3.3: Explain reasons for the exponential growth phase, the plateau phase and the transitional phase between these two phases • 5.3.4: List three factors which set limits to population increase

3. What determines population growth? • Natality, Mortality, Immigration, Emmigration • What type of species grow exponentially, with density independent growth? • R-selected species • What type of species shows density dependent growth that slows then plateaus over time? • K-selected species

4. So populations change by • Natality and Immigration increasing them • Mortality and Emigration decreasing them • So • Change = (N + I) – (D + E)

5. Figure 52.8 Population growth predicted by the exponential model

6. Figure 52.11 Population growth predicted by the logistic model

7. Phases of an S curve • Exponential phase = population increases because natality rate is greater than mortality rate • Resources abundant, diseases & predation rare • Transitional phase = natality rate starts to slow +/or mortality rate starts to increase. Natality still above mortality so population will still increase but less rapidly • Resources decreasing +/or Disease & Predation increase • Plateau phase = Natality = Mortality so population size remains constant • Something has limited the population • It has reached carrying capacity (K)

8. What is Carrying Capacity? • K = the maximum number of individuals that a particular environment can support at a particular time with no habitat degradation • What are the limiting factors that would cause carrying capacity? • Limiting factors include Energy (food) available, shelters, predators, diseases or parasites, soil nutrients, water, suitable nesting & roosting sites

9. Ecosystems 5.1 • 5.1.1 – Define ecology, ecosystem, population, community, species & habitat • 5.1.2 – Distinguish between autotroph (producer) and heterotroph (consumer) • 5.1.3 – Distinguish between consumers, detritivores and saprotrophs • 5.1.4 – Describe what is meant by a food chain giving three examples, each with at least 3 linkages (4 organisms) • 5.1.5 – Describe what is meant by a food web • 5.1.6 – Define trophic level • 5.1.7 – Deduce the trophic level of organisms in a food chain and food web • 5.1.8 – Construct a food web containing up to 10 organisms given appropriate information

10. 5.1.9 – State that light is the initial energy source for almost all communities • 5.1.10 – Explain the energy flow in a food chain • 5.1.11 – State that when energy transformations take place including those in living organisms, the process is never 100% efficient, commonly being 10 – 20% • 5.1.12 – Explain what is meant by a pyramid of energy and the reasons for its shape • 5.1.13 – Explain that energy can enter and leave an ecosystem, but that nutrients must be recycled • 5.1.14 – State that saprophytic bacteria and fungi (decomposers) recycle nutrients

11. Definitions • Ecology  the study of relationships between living organisms and between organisms and their environment • Ecosystem  a community and its abiotic environment • Population  a group of organisms of the same species who live in the same area at the same time • Community  a group of populations living and interacting with each other in an area • Species  a group of organisms which can interbreed and produce fertile offspring • Habitat  the environment in which a species normally lives or the location of a living organism • Trophic level  energy level in a food web / chain • Autotroph  organism which makes its own food from inorganic materials • Heterotroph  organism that depends directly or indirectly on producers for energy

12. What is a … • Consumer? • Eats another organism as an energy source – heterotrophic • Zebra, lion • Detritivore? • get their energy from detritus, nonliving organic material  remains of dead organisms feces, fallen leaves, wood • Dung beetles, earth worms • Saprotroph? • feed on dead organic material by secreting digestive enzymes into it and absorbing the digested products • Bread mold, mushrooms

13. Food chains are linear diagrams to show feeding relationships and energy flow

14. An Antarctic marine food web – no show organisms at multiple trophic levels to indicate the true complexity of the feeding relationships and energy flowCan you deduce the trophic level for each organism you see?

15. Now create a food web – remember the direction of your arrows!

16. The initial source of energy for most communities is the… • Sun

17. Explain the energy flow in one of these food chains What percent of the energy in zooplankton could be expected to be transferred to the small carnivorous fish? If there are 20 Joules of energy in a grasshopper, how much of that is left for the hawk?

18. Energy pyramids

19. So energy and matter move differently • Energy flows through the system – in from the sun out by heat • Matter must be recycled though because there is no new matter coming in to replace used matter

20. Syllabus statements • 5.4.1: Define evolution • 5.4.2: Outline the evidence for evolution provided by the fossil record, selective breeding of domesticated animals, and homologous structures • 5.4.3: State that populations tend to produce more offspring that the environment can support • 5.4.4: Explain that the consequence of the potential overproduction of offspring is a struggle for survival • 5.4.5: State that the members of a species show variation • 5.4.6: Explain how sexual reproduction promotes variation in a species • 5.4.7: Explain how natural selection leads to evolution • 5.4.8: Explain two examples of evolution in response to environmental change; one must be multiple antibiotic resistance in bacteria

21. Evolution Basics • Evolution = The change in the genetic composition of a population over time • Changes in gene frequency over time

22. Evidence for evolution • Evidence indicates that species evolve by natural selection over longer time periods • Evolution is validated by evidence from • homology similarities between species due to common ancestry • Selective breeding  Breeding organisms for specific traits • Biogeography  distribution of living species • Fossils  Form and distribution validate the theory

24. Principles of Evolution • Populations tend to produce more offspring that the environment can support • Members of a species show variation • The resources in the environment are limited • The consequence of the potential overproduction of offspring is a struggle for survival • Some variations are favorable in this struggle • Those individuals with favorable variations will pass on their genes to the next generation in higher numbers • Gene frequency changes to represent the fittest organisms “SURVIVAL OF THE FITTEST”

25. Consequences of Overproduction of Offspring • Food might become scarce • Territories might be limiting for both mating and reproducing • Density might get so great that disease and parasites would become epidemics • Predator populations will also grow because of the increase in population size of prey, and begin to whittle down the herd.

26. Role of Sex • Living organisms vary as a result of sexual reproduction • Meiosis allows a large variety of genetically different gametes to be produced by each individual (2n) • This occurs through segregation of maternal and paternal chromosomes and crossing over in prophase I of meiosis • Fertilization allows alleles from 2 different individuals to be brought together in one new individual

27. Evolution in response to environmental change: antibiotic resistence

28. Evolution in response to environmental change: pesticide resistence

29. Taxonomy syllabus statements • 5.5.1 – Outline the binomial system of nomenclature • Define species • 5.5.2 – List the seven levels in the hierarchy of taxa – kingdom, phylum, class, order, family, genus, species – using an example from two different kingdoms for each level • 5.5.3 Distinguish between the following phyla of plants, using simple external recognition features: bryophyta, filicinophyta, coniferophyta and angiospermophyta. • 5.5.4 Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, platyhelminthes, annelida, mollusca and arthropoda. • 5.5.5 – Apply and/or design a key for a group of up to eight organisms

30. Binomial Nomenclature System • Created by C. Linneaus • Each species has 2 part Latin name • Genus species (computer) • Genus species (handwritten) • E.g. Homo sapiens = humans Felis sylvestris = house cat Ranunculus acris = buttercut

31. Remember: KPCOFGS(memorize the following examples)

32. Organisms that are in a particular level of the taxonomic hierarchy together share all the levels above and may or may not share the levels below

33. Plants • Bryophyta: mosses, liverworts, hornworts – short, nonvascular, no roots, live in moist and harsh environments, • Filicinophyta: ferns, clubmosses, wiskferns, horsetails - vascular, spores, need water for reproduction, simple leaves, • Coniferophyta: conifers, cycads, ginkgo, and the gnetophytes – small waxy leaves, naked seeds, larger, • Angiospermophyta: flowering plants – fruits, flowers, most diverse, monocots and dicots

38. Animals • Porifera: sponges – sessile, lack tissues, filter feeders • Cnidaria: anemones, corals, hydra, jellies – nematocysts, radial symmetry, polyp or medusa • Platyhelminthes: flatworms – bilateral symmetry, flat, only one GI tract opening • Annelida: segmented worms (oligocheates, polycheates, hirudinea) – repeated segments on bilaterally symmetrical body • Mollusca: bivalves, cephlopods, gastropods, chitons – bilateral symmetry, 3 body parts foot, visceral mass, mantle • Arthropoda: insects, crustaceans – exoskeletons and jointed appendages

40. Create & Apply A Dichotomous Key

42. Syllabus Statements • 5.2.1: draw and label a diagram of the carbon cycle to show the processes involved • 5.2.2: Analyse the changes in concentration of atmospheric carbon dioxide using historical records • 5.2.3: Explain the relationship between rises in concentrations of atmospheric carbon dioxide, methane and oxides of nitrogen and the enhanced greenhouse effect • 5.2.4: Outline the precautionary principle • 5.2.5: Evaluate the precautionary principle as a justification for strong action in response to the threats posed by the enhanced greenhouse effect • 5.2.6: Outline the consequences of a global temperature rise on arctic ecosystems

43. Figure 54.17 The carbon cycle

44. Greenhouse Effect & Global Warming • Incoming short wave radiation (visible and UV) is transmitted through the atmosphere • Much of solar radiation that strikes the planet is reflected back into space • Although CO2 and water vapor in the atmosphere are transparent to visible light, they absorb much of the reradiated long wave radiation (infrared radiation) • Some reflected back and retained to heat up the earth • If not for the natural Greenhouse effect the earth’s surface temperature would be 18 oC  most life would not exist

46. So… • Main atmopsheric gases involved are CO2, methane, water vapor, CFC’s • If we put more of those gases into the atmosphere from our activities, we should expect a corresponding increase in temperature • Do we put in more?

47. Human activities increase the Greenhouse Effect • Gases: CO2, methane, water vapor, CFC’s • CO2 Released from combustion of fossil fuels (coal, oil natural gas) • Burning of wood from deforestation • Methane release from the digestive tracts of ruminants (cows) • Swamps, rice paddies, landfills • CFC’s used as refrigerants, propellants in cans, gas blown plastics

50. Historical Records • We see trends of increased CO2 emissions in measures taken since 1950’s • Mona Loa and Cape Grim Tazmania, show fluctuating increase • Peaks in our winter, dips in our summer – depends on photosynthesis • Longer term trends in CO2 seen in ice core data