Intro to Ecology

1. Intro to Ecology

2. What is Ecology?? • The study of interactions that take place between organisms and their environment. • It explains how living organisms affect each other and the world they live in.

3. Habitat & Niche • Habitat is the place an organism lives • Niche is an organism’s total way of life

4. The Nonliving Environment • Abiotic factors- the nonliving parts of an organism’s environment. • Examples: • air currents, • temperature, • moisture, • light, • Soil nutrients.

5. The Living Environment • Biotic factors- all the living components of an environment. • All organisms are affected by both biotic and abiotic factors in their niches

6. Abiotic or Biotic? Biotic

7. Abiotic or Biotic? Abiotic

8. Abiotic or Biotic? Abiotic

9. Abiotic or Biotic? Biotic

10. Human Impact What are humans doing to the ecosystems of the world?

11. What have humans done? • ozone layer - created a hole is this layer that protects us from UV radiation due to Chlorofluorocarbon (CFCs) • greenhouse effect- this NATURAL effect keeps the Earth warm, but due to pollution, humans are amplifying this effect and making it warmer than usual (overloading the carbon cycle with too much CO2, a greenhouse gas) • Smog and acid precipitation are caused by air pollution

12. What have humans done? • All of these things have had a hand in changing ecosystems and communities world wide • Many Ecologist study human impact on communities by looking at: • Biological magnification • Keystone species • Bioindicators

13. Biological magnification • Land and water pollution can be a big problem for many organisms • Chemical that we use on farms and in our homes can be toxic to wildlife • Many chemicals that enter an ecosystem undergo biological magnification, a process in which chemicals become more concentrated as they move up the food chain

14. Fewer amounts of predators at higher levels means more poison in each organism

15. Keystone species • These are species that can affect many other species in a community • When these species become extinct, or scarce, the entire community changes and usually many species disappear • Increase biodiversity

16. Keystone Species Sea Otters were hunted to near extinction in the Pacific Ocean until people realized that their disappearance caused everything in their food chain to disappear

17. Bioindicators • These are species that are especially sensitive to change • Frogs are bioindicators because they live in or around water (which is where pollutants tend to accumulate) and they absorb gases through their skin • Many people believe that the world wide decline in frog populations is an indicator of population declines in other species

18. Sustainability • Means the ability to meet human needs in such a way that the human population can be maintained indefinitely • To do this, we need to make sure our resources (like food, space and water) will always be available • This includes keeping the Earth healthy and maintaining biodiversity • Biodiversity- refers to the variety of forms of life in an area • If we keep doing what we are doing this is not going to happen

19. Growth Rate • Growth rate- the amount by which a population size changes over a given time • In order for a population to grow, the birth rate (number of individuals born) must be greater than the death rate (number that die) • Population size constantly changes in any given population due to changes in growth rates

20. Can populations grow infinitely? • NOOO!! • Every ecosystem has a Carrying capacity • This is the maximum number of organisms that can be supported in a given habitat. • The carrying capacity of a habitat is based on limiting factors

21. What are limiting factors? • Any factor that restrains the growth of a population. For example…Space, Food, Water, or Soil Nutrients • When limiting factors become scarce, organisms begin to compete for them. In this competition, some will win (survive) and some will lose (die) • This can also cause a population to decline • No ecosystem can support an infinite amount of organisms…eventually there is a limit. • When limiting factors run out, carrying capacity is reached and populations decline

22. Population Ecology

23. Population Ecology • Population Ecologists study many factors dealing with population, the three most important are… • population density • growth rate • Carrying capacity

24. Population Density • Population density measures how crowded a population is • The population density of the US is about 30 people per square kilometer (0.6 mi2) • In Japan it is 337 people/km2 • (Data from 2003)

25. Levels of Organization • Ecologists have organized species interactions into different levels

26. 1st Level of Organization • Organism:An individual living thing

27. 2nd Level of Organization • Population:A group of the same species, which live in the same area and interbreed

28. 3rd Level of Organization • Community:All the populations of different species that live in the same place at the same time.

29. 4th Level of Organization • Ecosystem: the community AND the abiotic factors of an area.

30. 5th Level of Organization • Biosphere:The portion of Earth that supports life. • It is about 20 km (13 mi) wide from deepest parts of ocean to 8-10 km above the surface • If the Earth were an apple, the biosphere would be the skin

31. Levels of Organization OrganismPopulationCommunity Ecosystem Biosphere

32. Energy Relationships Vocab • Producers are the autotrophs of an environment • Mostly by photosynthesis • Consumers are the heterotrophs of the environment. They can be… • Herbivores- which eat producers • Carnivores- which eat other consumers • Omnivores- which eat producers and consumers

33. Energy Relationships Vocab • Primary comsumer- eats producer • Secondary consumer- eats primary • Tertiary consumer- eats secondary • Detritivores - (Decomposers) - Break down complex molecules in dead organic matter into smaller molecules • They are responsible for recycling many nutrients into the soil

34. Food Chains • Food Chains- A single pathway of energy relationships among organisms in an ecosystem

35. Food Chains • The arrows DO NOT merely show what gets eaten • The purpose of the arrows is to show where the energy is going • Scientists refer to eating as an energy transfer, because when one organism eats another, the main goal is to get energy from the organism. • SO, the arrow points at the organism that GETS the ENERGY (the organism doing the eating)

36. Food Webs • Food chains are a very inaccurate depiction of feeding relationships in an ecosystem…Food webs are more accurate • Food webs are interrelated food chains of an ecosystem

37. Make a food chain from this food web

38. Food Webs • Decomposers are sometimes shown in food chains and food webs • Eventually all organisms give their remaining energy to decomposers

39. Trophic Levels • Each organism in a food chain or web represents a trophic level • The trophic level is an organisms position in a sequence of energy transfers (in a food chain or web) • Notice Higher on the food chain means higher trophic level producer primary consumer secondary consumer tertiary consumer 1st level 2nd level 3rd level 4th level

40. Trophic Levels tertiary consumer • A top level carnivore means that NOTHING in that environment is able to eat it. • Organism CAN be at more than one level • In this diagram, a fox eats a snake, but it eats insects also, it would be both a secondary and tertiary consumer • In real life, many organisms are at 2 or more levels. secondary consumer primary consumer producer

41. Energy Transfers • Producers add biomass (Organic material) to environments • They are always at the bottom of the food chain or web. • So they are the origin of the energy • BUT…Producers get their energy from the sun • So, THE SUN IS THE ULTIMATE SOURCE OF ENERGY IN ALMOST ALL ECOSYSTEMS

42. Energy Transfers • Energy transfers within an environment are often shown using an Energy Pyramid: • Notice that energy is lost as you move up the pyramid • Notice also that low trophic levels are at the bottom and higher levels are at the top

43. Energy Transfers • Very little energy (10%) is transferred when one organism eats another. Why is this? • Not all organisms are eaten at any given level • Consumers cannot break down all of the organic material in their food • Organisms use the energy they make or consume for themselves and do not store it, some of the energy organisms consume is lost as heat during digestion

44. Stored Energy at each level

45. Stored Energy at each level 1 Cal 10 Cal 100 Cal 1000 Cal

46. Energy Transfers • This low rate of energy transfer if the reason that as you move up a food chain, there are less organisms at higher trophic levels • There is not enough energy to support the organisms at higher levels

47. Less organisms at the top means less biomass

48. Nutrient Cycling Atoms around today have been the same since the beginning of life on Earth These atoms are constantly being used, reused, and recycled. (CYCLED) Theses cycles are called biogeochemical cycles

49. The Carbon Cycle

50. The Carbon Cycle CO2 is taken out of the air by plants (photosynthesis) CO2 is put in the air by burning, decomposition, and respiration Remember, the organic molecules that make us (proteins, carbs, fats, nucleic acids) are made of carbon, which we get by eating