Ecology

1. Ecology AP Biology

2. Ecology Background Terms • Population-a group of individuals of the same species living in the same area • Community- a group of populations in the same area • Ecosystem- the interrelationships between the organisms in the community and their physical environment • Biosphere- all of the ecosystems on earth • Habitat- a place where an organism lives • Niche- describes all the biotic (living) and abiotic (nonliving) resources used by an organism in the environment- their place in the ecosystem is their niche

3. Population Ecology • The study of the growth, abundance and distribution of populations. Described by: • Size of a population- symbolically represented by N- is the total number of individuals in the population • Density- the total number of individuals per unit of space • Dispersion- how individuals in the popuilation are distributed. They may be clumped (humans in cities), uniform (trees in an orchard), or random (trees in some forests) • Age structure- the abundance of individuals of different ages • Survivorship curves- describe the mortality (death) of individuals during different parts of their lifetimes

4. Age Structure Pyramids

5. Survivorship Curves • Type I curves- species in which most individuals survive to middle age, after that mortality is high. EX- humans • Type II curves- species in which the length of survivorship is random- the likelihood of death is the same at any age. EX- rodents • Type III curves- species in which most individuals die young. EX- oysters

7. Terms Describing Population Growth • Biotic Potential- maximum growth rate of the population under ideal conditions • Carrying capacity- maximum size of the population in a particular habitat • Limiting factors- anything that limits the size of a population. They can be: • Density dependent- limit the size of a population based on how close the organisms are to each other. EX- diseases • Density independent- limit the size of a population regardless of how close they live to each other EX- natural disasters

8. Population Growth • Exponential Growth- occurs when a the reproductive rate is greater than zero. On a graph, exponential growth forms a J-shaped curve. • Logistic Growth- occurs when limiting factors restrict the size of the population to the carrying capacity of the habitat. On a graph, it forms an S-shaped curve

9. Reproductive Strategies • There are two types: 1. R selected species- exhibit rapid exponential growth. This type of reproductive strategy is characterized by opportunistic species- such as grasses and many insects- that quickly invade a habitat, quickly reproduce, and then die. They produce many offspring that are small, mature quickly and require little (if any) parental care. 2. K selected species- population size remains relatively constant at the carrying capacity. Species of this type, such as humans, produce a small number of relatively large offspring that require extensive parental care.

10. r is the growth rate of the population (N), and K is the carrying capacity of its local environmental setting. Typically, r-selected species exploit less-crowded ecological niches, and produce many offspring, each of which has a relatively low probability of surviving to adulthood. In contrast, K-selected species are strong competitors in crowded niches, and invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood. In the scientific literature, r-selected species are occasionally referred to as "opportunistic", while K-selected species are described as "equilibrium"

11. Human Population Growth • A thousand years ago the human population began undergoing exponential population growth. This was made possible by: • Increases in food supply due to domesticating animals and plants, as well as technological advances in farming (such as enriching soil with nitrogen) • Reduction in disease- advances in medicine, such as antibiotics, vaccines, and proper hygiene • Water purification and sewage systems- reduce health hazards • Expansion of habitat- better housing, warmer clothing, access to energy for heating/cooling/cooking, transportation

12. Human Population Growth

13. Community Ecology • Is concerned with the interaction of populations. One form of interaction is interspecific competition (between two different species). The following are ways this competition can be resolved: • Competitive Exclusion Principle- when two species compete for exactly the same resource (or occupy the same niche) one species will eventually outcompete the other. No two species can occupy the same niche • Resource partitioning- some species coexist in spite of apparent competition for the same resources. This is because they actually pursue slightly different niches. EX- five species of birds coexist in the same type of tree by feeding on insects in different regions of the tree.

14. Resource Partitioning

15. Niches • Fundamental Niche- the niche an organism occupies in the absence of competing species • Realized niche- the actual niche the organism occupies when competition is present

16. Cline •  the gradual change in certain characteristics exhibited by members of a series of adjacent populations of organisms of the same species

17. Competition • Competition- both species may be harmed when struggling to gain the same resources • Intraspecific- competition within the same species • Interspecific- competition between different species

18. Predation • Can be categorized as follows: • A true predator kills and eats another animal • A parasite spends most or all of its life living on another organism (the host) • A parasitoid is an insect that lays its eggs on a host and the larvae eat the host when they hatch • A herbivore is an animal that eats plants. Some may consume the entire plant.

19. Predator Prey Relationships Quick intro: https://www.youtube.com/watch?v=ZWucOrSOdCs Research methods (hare): https://www.youtube.com/watch?v=tOUEgqyGnrw

20. Symbiotic Relationships • Symbiosis- when two species live together in close contact. There are different types: • Mutualism- both species benefit. EX- acacia trees provide food and shelter for ants. The ants kills any insects, fungus, or vegetation on or near the tree • Commensalism- one species benefits, the other is unaffected EX- birds nest in trees • Parasitism- one species benefits, the other is harmed EX- tapeworms

21. 3 Symbioses • https://www.youtube.com/watch?v=WcQ5_zaJob0

22. Competition • Competition- both species may be harmed when struggling to gain the same resources • Intraspecific- competition within the same species • Interspecific- competition between different species

23. Coevolution/Defense Mechanisms • In the contest between predator and prey, some have evolved unique heritable characterists: • Secondary compounds- toxic compounds made by plants that discourage herbivores. EX- tobacco plants • Camouflage (cryptic coloration)- allows organisms to blend in EX- leaf and stick bugs Top 10 weird defenses: https://www.youtube.com/watch?v=2P7sLWqmK3w

24. Coevolution/Defense Mechanisms • Aposematic coloration- is a conspicuous pattern or coloration that warns predators that they sting, bite, or taste bad • Mimicry- When two species resemble one another in appearance. There are two types: • Mullerian mimicry- where both animals are dangerous. They share the same appearance- this is thought to teach predators through power in numbers. EX- wasps and bees • Batesian mimicry- one species is harmful, but the other is harmless and gains protection by pretending its dangerous. EX. Some species of flies/beeltes have yellow and black markings to resemble bees.

25. Succession • Succession- change in species composition in a community over time. Primary succession occurs when a new habitat forms- such as with a volcanic island. Secondary succession occurs after a natural disaster. • Some of the changes that occur include: • Pioneer species are the first species to start growing. They tolerate intense conditions. • Substrate texture may change from solid rock to sand or to fertile soil as rock erodes and plant and animal decomposition occurs • Soil pH may decrease due to the decomposition of materials such as leaves • Soil ability to retain water may change. • Light availability may change • Crowding may push out certain species • The final community structure that forms is called the climax community

26. https://www.youtube.com/watch?v=V49IovRSJDs

27. Energy Flow in Ecosystems • Trophic Level- a level in a food chain • Primary producer- autotrophs that convert light energy into chemical energy. Include plants, photosynthetic protists, and cyanobacteria • Primary consumers- herbivores- eat primary producers • Secondary consumers- or primary carnivores- eat the primary consumers • Tertiary consumers- eat secondary consumers • Detritovores- consumers that obtain their energy by eating dead animals and plants (detritus). The smallest detritovores are called decomposers and include bacteria and fungus. Others include earthworms and vultures.

28. Energy Flow in Ecosystems • Food chains- a linear flow of who eats whom • Food webs- many food chains put together • As you go up a food chain- only about 10% of the energy is passed along- the other 90% is used by the organism for metabolic activities. • Trophic level- a level in a food chain

29. Watch the video: http://www.youtube.com/watch?v=CReZd9OHEfs and then • Using the information from the following website generate a FRQ question or a Grid-In question about Energy Flow in Ecosystems • https://docs.google.com/document/d/1c6O95KovdS6mxiwaSuCu2DbfabD4P2fQlF6H4FNco98/edit?hl=en_US

30. Biogeochemical Cycle • Describe the flow of essential elements from the environment to living things and then back to the environment. • We will look at the major storage locations for each element (reservoirs), the processes through which each element incorporates into terrestrial plants and animals (assimilation) and the processes through which it’s released back into the environment.

31. Water Cycle • Reservoirs- oceans, air (as water vapor), groundwater and glaciers. • Evaporation, wind and precipitation move water from oceans to land. • Plants absorb water from the soil. • Animals drink water or eat other organism and use their water. • Water is release from plants through transpiration and from animals when they sweat. Released from both when they die and decompose.

32. Carbon Cycle • Carbon is required for the building of all organic molecules • Reservoirs- atmosphere (as CO2), fossil fuels (coal, oil) • Plants use CO2 for photosynthesis • Animals consume plants and obtain their carbon in organic molecules • Animals breathe out the carbon in CO2 • CO2 is released when anything is burned

33. Nitrogen Cycle • Nitrogen is required for making all amino acids and nucleic acids • Reservoirs- atmosphere (N2) and soil • Plants absorb nitrogen as either NO3 or NH4 • Animals obtain nitrogen by eating plants or other animals • Animals excrete nitrogen is in their urine • Nitrogen is put into the soil from the atmosphere (nitrifiation, nitrogen fixation) and removed from the soil to the atmosphere (denitrification)by bacteria

34. Phosphorus Cycle • Phosphorus is required for the manufacture of ATP and all nucleic acids. • Reservoirs- rocks • Plants absorb phosphorus from soils • Animals obtain phosphorus from eating plants and other animals • Plants and animals release phosphorus when they die and decompose. • Animals excrete phosphorus is in their urine

35. Biomes • Biomes- regions that have common environmental characteristics • Tropical rain forests- high temperatures and heavy rainfall. Tall trees, but little growth on the forest floor due to a lack of light. • Savannas- grasslands with scattered trees. Tropical with high temperatures, but less water than rain forests. • Temperate grasslands- less water and lower temperatures than savannas. • Temperate deciduous forests- warm summers and cold winters where trees drop their leaves. • Deserts- hot and dry. Animals and plants have adaptations to deal with harsh conditions.

36. Biomes • Taigas- coniferous forests. Cold winters and precipitation in the form of snow. • Tundras- winters so cold the ground freezes. During the summer, the upper topsoil thaws, but the deeper soil (called permafrost) stays frozen. • Fresh water biomes- ponds, lakes, streams, rivers • Marine biomes- estuaries (where rivers meet oceans), and the ocean

37. Biomes

38. Biome video • https://www.youtube.com/watch?v=v7cZ3b6PH2s • During the video take notes on the major characteristics of each biome on your study guide.

39. Human Impact on Biosphere • Human activity damages the environment: • Greenhouse effect- the burning of fossil fuels increases carbon dioxide in the atmosphere. The increased carbon dioxide causes more heat to be trapped near the earth’s atmosphere. As a result, global temperatures are rising. This could raise sea levels by melting more ice. • http://climate.nasa.gov/causes

40. Human Impacts • Ozone depletion- the ozone layer form in the upper atmosphere when UV radiation make O2 form O3 molecules (ozone). The ozone absorbs UV radiation and prevents it from reaching earth where it can damage the DNA of plants and animals. Pollutants such as CFCs (chlorofluorocarbons) have been used as refrigerants and propellents and remove O3 from the atmosphere. This has left major areas of thinning called ozone holes.

41. Human Impacts • Acid rain- burning fossil fuels and other industrial pollutants contain sulfur dioxide and nitrogen dioxide. When they react with water they produce sulfuric acid and nitric acid. They return to the soil in rain or snow and can kill plants and animals. • Desertification- Overgrazing of grasslands that border deserts transform grasslands into desert. • Deforestation- Clear cutting of forests causes erosion, flooding, and changes in weather patterns. The slash and burn method of clearing tropical rainforests for agriculture increases atmospheric carbon dioxide, contributing to the greenhouse effect. Because most of the nutrients in rainforests are stored in the plants, the soil is poor and can only support agriculture for a few years.

42. Human Impacts • Biological Magnification- some pollutants, such as the pesticide DDT or mercury, are not broken down in the environment and accumulate in the fatty tissues of organisms. As you go up in a food chain the concentration of these pollutants is higher. The biological magnification of DDT led to several species of birds, including the bald eagle, nearly going extinct.

43. Human Impacts • Algal Blooms- can be caused by fertilizer or sewage running off into a lake. When the algae eventually die, bacteria break them down, and the bacterial growth depletes oxygen in the lake. The result is oxygen starvation for many animals, including fish and invertebrates. This is called eutrophication. • Reduction in speciesdiversity- as a result of human activities- including habitat destruction, and hunting/poaching