Ecology

1. Ecology To Those Who Shall Inherit the Earth…

2. Flow of Energy Love is energy and energy is everything

3. What is an Ecosystem? • Interactions among biotic (living) and abiotic (nonliving) factors • Let’s try to draw one

4. How does energy move? • Essentially all energy comes from the sun • Moves from autotrophs (plants) to heterotrophs (not plants) • Heterotrophs (aka. Consumers) – must consume energy; cannot make their own • Autotrophs (aka. Producers) – Produce their own energy • Most use radiant energy from the sun to produce chemical energy in the form of glucose sugar • What is this process called? Photosynthesis!

5. What about the other producers? • MOST use photosynthesis to produce energy • Others use energy from chemical reactions to produce organic molecules • Called Chemosynthesis • Bacteria and archaea

6. How do other organisms obtain energy? • Heterotrophs or consumers – take in energy by breaking down compounds in organisms they eat • Trophic levels: • Producers • Primary consumers – eat producers • Secondary consumers – eat primary consumers • Tertiary consumers – eat secondary consumers • Quaternary consumers – eat… guess what they eat? • Organisms participate in different levels

7. What are decomposers? • Usually fungi or bacteria • Decomposers obtain energy from organic wastes • fallen leaves or dead organisms • Fungi usually break down plant matter • Bacteria usually break down animal matter • Break down complex molecules into simpler ones • Helps cycle carbon and nitrogen elements • Use secreted enzymes to break down food • Enzymes – special proteins that speed up reactions

8. Are there ways to show energy flow? • There are 2! • Food chains – path of energy from producer to decomposer • Food web – chains that interconnect through multiple feeding relationships • Arrows point the direction of energy flow from one organism to the next (What’s doing the eating) • Energy travels in 1 direction • Energy does NOT cycle through the ecosystem, unlike matter • What would be the simplest food chain? Producer  consumer Chain Web

9. What types of eating habits are there? • Herbivore – eats only producers (eats plants) • Omnivore – eats both producers and consumers (eats plants and animals) • Carnivore – eats consumers (eats meat only)

10. Is there a model for energy flow? • Lets go back to the ecosystem drawing • Models are visual depictions that make a feature of the world easier to understand and are used to make predictions and test hypotheses etc… • Food pyramids are models for energy flow • Must show feeding relationships in food chains as well as amount of energy passed up trophic levels • 10% of energy is ALL that passes to the next trophic level

11. Checkpoint • Use the following food chain to create an energy pyramid: Grass  mouse  snake  hawk • If the amount of energy present in the producers of this pyramid is 1.35 x 105 kilocalories, identify how much energy is present in each trophic level • What if we add decomposers to consume the hawk after it dies?

12. Assignment! • Paper – pencil food chain lab • Complete the packet – due tomorrow • Materials • Packet • Writing utensil (no red, pink, or green) • Scissors • Glue

13. Biogeochemical cycles What goes around comes around

14. What are biogeochemical cycles? • Bio = life • Geo = earth • Chemical = chemical • So, biogeochemical cycles are the patterns that elements and chemicals move through and between biotic organisms and their abiotic environment • 3 major cycles include: • Carbon – oxygen cycle • Nitrogen cycle • Water

15. How does the carbon-oxygen cycle work? • C and O exist in all organisms • Both exist in the atmosphere as CO2 and O2 • Steps • Plants take in CO2 using _____________ and convert it into carbohydrates • Plants release O2 • Animals take in O2 and release through CO2 respiration • Decomposers break down C stored in dead organisms and return it to the atmosphere photosynthesis

16. What is the “geo” part of the carbon-oxygen cycle? • Carbon is also released into the atmosphere by: • burning fossil fuels • Volcanic eruptions • Human or naturally caused forest fires

17. Where do fossil fuels come from? • Carbon in the bodies of deceased organisms that lived millions of years ago were subjected to heat and pressure deep within Earth turning them into fossil fuels • Any combustion reaction (anytime you burn organic things), CO2 and water vapor are produced AND oxygen is consumed • Burning fossil fuels • Burning wood for fuel/forest fires • Forest fires

18. What is the nitrogen cycle and why is it important?? • Movement of nitrogen through the organisms, water, rocks, minerals, and atmosphere • Nitrogen is ESSENTIAL to living things as it makes up: • Nucleic acids and DNA • Amino acids and proteins • ATP (high energy molecule used for cellular energy)

19. How does nitrogen move through the cycle? • Atmosphere contains approximately 78% nitrogen… that most organisms cant use • Nitrogen fixation into ammonia (ammonification)changes nitrogen into a usable form for organisms done by: • Soil bacteria • Certain plants, called legumes, have a mutualistic relationship with certain bacteria that allow nitrogen fixation • Ex. Peanuts, most beans, and peas

20. What happens after the nitrogen is fixed? • Assimilation - Plants absorb nitrogen once it is in the form of usable nitrates • Animals obtain nitrogen by eating plants • Nitrogen in animals is passed through the food chain and returned to decomposers • In low oxygen environments bacteria convert nitrogen to gas which returns to the atmosphere = denitrification • Marine environments • Soil

21. What is the hydrologic cycle? • Water cycle • Driven by energy from the sun • Important steps: • Evaporation – liquid to gas by energy from sun or heat • Condensation – gas to liquid • Precipitation – falls • Respiration – water vapor produced by cells when breaking down glucose • Transpiration – liquid to gas through plants • Vascular plants (large plants) use a tissue called xylem to move water up the plant • Water leaves through holes in leaves called stomata

22. Assignment! • Complete the worksheet for biogeochemical cycles • Color AND answer questions • Use the document to help you answer questions • Materials • Colored pencils or crayons • Pencil • Due tomorrow

23. Symbiotic Relationships Living together isn’t always easy

24. What is the hierarchy of biological systems? • Atoms – come together to make: • Molecules – come together to make: • Organelles – come together to make: • Cells - come together to make: • Tissues - come together to make: • Organs - come together to make: • Organ systems – come together to make: • Organism - come together to make: • Populations - come together to make: • Communities - come together to make: • Ecosystems - come together to make: • Biosphere We’ll focus on these for now

25. What are the parts of ecology hierarchy?? • Population - A group of organisms of the SAME species living together • Community – A group of organisms of DIFFERENT species living together • Ecosystem – A group of living and non-living things in an environment • Biosphere– all living things on Earth

26. How do ecosystems remain stable? • Population of individual species will cycle regularly and predictably as energy flow remains fairly constant • Organisms live in habitats • Depends on availability of water, shelter, and food • The role and organism plays in its environment is its niche • What it eats, where it eats, and its effect on the environment

27. Can organisms occupy the same habitat and niche? • Organisms may have the same habitat • Organisms may NOT have exactly the same niche within the habitat • 2 plants may both live in the same habitat – occupy the same niche – but they may require different amounts of light

28. Can organisms live together? • Yes these types of relationships are called symbiotic/symbiosis • Symbiosis is an interdependent relationship between two different organisms or a different species – at least 1 of them ALWAYS benefits • Mutualism – both species benefit • Commensalism – one organism benefits and the other is unaffected • Parasitism – one organism benefits and one is harmed Each X represents a different organism

29. Assignment! • Symbiotic relationships cut and paste • Due tomorrow • Materials: • Scissors • Glue or tape • Worksheet

30. What about other relationships? • Predator – prey: one organism kills and eats another • Key role in the ecosystem keeping population sizes balanced • Populations that are too high are prone to: • Starvation • disease

31. What about organisms that require the same things? • They compete: interact where they try to use the same resources at the same time • Intraspecific competition – organisms of the same species compete for food, water, shelter, mates • Interspecific competition – organisms of different species compete for food, water, shelter • Most successful competitors are best adapted to their ecosystem

32. Assignment • Online virtual lab examining competition • Found here: http://glencoe.mheducation.com/sites/dl/free/0078757134/383928/BL_04.html • Materials: • Computer • Internet • Handout • Pen/pencil

33. Why do organisms communicate? • They communicate to their own and to other species • Helps organisms survive by allowing them to: • ID themselves • Attract mates • Warn of predators • Protect living space – territory (can be small or large) • Many animals use chemical markers to identify their territory • Many animals use sound to warn another animal they are encroaching • Many animals will fight to defend their territory

34. How do organisms communicate? • Sound • Ex: Whale songs, wolf howls, your nonstop chatter • Visual • Ex. Waggle dance in bees, courtship dances • Chemical • Ex. Pheromones – chemicals used by one organism to elicit a response from another (used by bees, ants, etc…)

35. Assignment! • Population dynamics worksheet • Due tomorrow • Materials: • Two colored pencils or pens (you may use patterns on your graph to distinguish between species if you wish to use 1 pencil or pen) • Graphing worksheet

36. Population dynamics What goes up must come down

37. Brief Review: • What is a population? • All the organisms of the same species living in an area • What is the hierarchy of ecology? • Organisms  population  community  ecosystems  biosphere • Tell me the factors discussed so far that determine population change? • Number of predators • Amount of resources (food, water, shelter) • Number of mates • Disease

38. What makes up an ecosystem? • Biotic factors – living things • Other organisms: bacteria, plants, animals, fungi, protists (5 kingdoms) • Abiotic factors - non living things • Rocks, sunlight, temperature, precipitation, inorganic chemicals (sodium, nitrogen, potassium, etc…)

39. How do populations grow and decline? • Affected by 4 factors: • Births • Deaths • Immigration – movement of organisms INTO an area • Emigration – movement of organisms OUT OF an area • Population equation: • Pop. = (births + immigration) – (deaths + emigration) • When (deaths + emigration outnumber (births + immigration), what happens to the population?

40. What makes birth and death rates rise? • Birth rates: • Usually higher in developing countries • Tend to rise when there is a need for more people to work • Death rates: • Usually higher in developing countries • Result from lack of food and water • Also result from lack of medical care and sanitation (enable rapid spread of disease)

41. What makes birth and death rates fall? • Birth: • Usually lower in developed countries • Increase cost in having children • Death: • Usually also lower in developed countries • Better medical care • Better sanitation and personal hygiene • Better access to food and water • Changes in population • If population cannot adapt to changing environments they decline • If populations do adapt to changing environments they increase

42. Is there selection for survival? K selection (think kanagaroo) R selection (think roaches) Many babies born to an individual organism Little to no parental care Quick maturation Short gestation Short life span • Few babies born to an individual organism • High amount of parental care • Slow maturation • Long gestation • Long life span

43. Assignment! Estimating population lab part 1 Estimating population lab part 2 Random sampling Materials: Paper for cutting 2 baggies Scissors (optional) Handout Pencil/pen • Mark and recapture method • Materials: • plastic baggie • A lot of white beans • 10 black beans • Handout • Pencil/pen

44. What limits population size? • Most population stabilize over time or reach carrying capacity • Carrying capacity – number of organisms an environment can support • Limiting factors – are biotic or abiotic things in the environment that control population • Number of predators – biotic • Disease – biotic • Amount of food – biotic (food is organic) • Precipitation – abiotic • Sunlight – abiotic • Amount of water – abiotic

45. What kind of limiting factors depend on population density? • Density – dependent limiting factor – limits the population based on the size of the population • Biotic factors • Have more affect on the population when numbers are high • Include: • Competition • What do organisms compete for? • Predation • Parasitism • Disease • Tuberculosis

46. What kind of limiting factors don’t depend on population density? • Density-independent limiting factors – control growth of population regardless of density • Abiotic factors • Do not depend on the size of the population to control population • Include: • Forest fires • Droughts • Tsunamis • Other natural disasters • Pollution caused by humans

48. When does a population stabilize? • Populations are stable when they reach their carrying capacity • Carrying capacity – the number of organisms an ecosystem can supportdue to limited resources • Can change as amount of resources change • Creates an S shaped curve on a population graph • What’s happening to the factors in the population equation?

49. How is carrying capacity affected by ecosystems? • Depends on: • number of organisms living there • Size of the ecosystem • Available resources • Rainforests have higher carrying capacity than a desert • Large areas of land have higher carrying capacities than small areas of land

50. What happens when a population does not stabilize? • Exponential growth – population continues to grow and does not show presence of limiting factors • J shaped curve • Only population known to currently do this is humans