Behavior / Ecology

1. Behavior / Ecology AP Biology

2. AP Biology Review Another Resource: Biology Web Pagehttp://faculty.clintoncc.suny.edu/faculty/michael.gregory/default.htm

3. Behavior • How an organisms responds to an environmental condition (stimulus) • Natural selection favors behaviors that increase chance of survival and reproduction • Innate behavior (nature) • inborn, not learned • Rigid, and unchangeable … good for stable env. • Newborns are ready for action • Learned behavior (nurture) • acquired via experience

4. Innate Behaviors • Reflex • Involuntary response • Advantage: able to react quickly • Fixed-action potential (FAP) • Instinct triggered by an object or event • One specific behavior • If an egg rolls out of a goose's nest, the goose stretches her neck until the underside of her bill touches the egg. Then she rolls the egg back to the nest. If someone takes the egg away while she is reaching for it, the goose goes through the motions anyway, even without an egg. • Jealous stickleback males were so attuned to the red stripe that they tried to attack passing British mail trucks, which were red, when they could see them through the glass of their tanks. • Complex programmed behavior • FAPs with a more complex series of steps • Female digger wasp building an nest • Birds making nests • Beavers making a dam Behavior - Real-life applications

5. Ecology • Ecology • The study of organisms and their interaction with the environment • Biotic Factors • All the living parts of the environment • Abiotic Factors • All the non-living parts of the environment

6. Biogeochemical Cycles • There are a few types of atoms that can be a part of a plant one day, an animal the next day, and then travel downstream as a part of a river’s water the following day. • These atoms can be a part of both living things like plants and animals, as well as non-living things like water, air, and even rocks. • The same atoms are recycled over and over in different parts of the Earth. This type of cycle of atoms between living and non-living things is known as a biogeochemical cycle. • All of the atoms that are building blocks of living things are a part of biogeochemical cycles. The most common of these are carbon and nitrogen.

7. Carbon-Oxygen Cycle

9. Nitrogen Cycle • Nitrogen is an element. Atoms of nitrogen don't just stay in one place. They move slowly between living things, dead things, the air, soil and water. These movements are called the nitrogen cycle.

10. Water Cycle

11. Factors limiting geographic distribution of species? How does introduction of new species to environment create potential problems?

12. Survivorship Curves • Type I - Human • High survival rate until old age • Type II – Squirrel • Constant proportion of individuals die at each age • Type III – Oyster • Increased chance of death as larvae and decreased later

13. Population Growth Predictions • Exponential growth will continue if resources are available • Logistic growth show rapid increase until the carrying capacity is reached and then levels out

14. Life strategies • r-stategy (Unstable Environment) • Density-independent selection • Maximizes rate of increase (r) • Populations fluctuate from well below and above carrying capacity • Many young • Little energy investment in each • Small young • Rapid sexual maturity • Examples • Mice, mosquitoes, weeds • lynx/hare (Fig. 52.19) • Dungeness Crab (Fig. 52.18) • K-stategy (Stable Environment) • Density-dependent selection • Maximizes population size and stays close to carrying capacity • Few young • High energy investment in each • Large young • Slow sexual maturation • Elephants, humans, oaks Organisms that live in stable environments tend to make few, "expensive" offspring. Organisms that live in unstable environments tend to make many, "cheap" offspring. http://www.bio.miami.edu/tom/courses/bil160/bil160goods/16_rKselection.html

15. Human Population Growth Curve • Exponential • What’s the carrying capacity? • When will we reach it • Will there be a major crash like bacteria in a closed container?

16. Ecological Footprint • Takes into account • Arable land • Pasture • Forest • Ocean • Built-up land • Fossil energy land • Example of US • Ecological footprint of 8.6 • Only 6.2 available per person Interpretation: We’ve exceeded our carrying capacity!

17. Goal of Ecology • Compute Energy Budgets • Individuals • Populations • Communities • Ecosytsems • Trace Energy Flow • Food Chains • Food Webs

18. Communities and ecosystems • How is energy flow through an ecosystem related to trophic structure (trophic levels)? • How do elements (e.g., carbon, nitrogen, phosphorus, sulfur, oxygen) cycle through ecosystems? • How do organisms affect the cycling of elements and water through the biosphere? • How do biotic and abiotic factors affect community structure and ecosystem function?

19. Laws of Chemistry/Physics apply to Ecosystems

20. 1st law of thermodynamics • Conservation of energy: energy cannot be created or destroyed but only transformed or transferred • Input: solar radiation • Rearrangment: CO2 and H2O form glucose which is used to generate ATP • Output: heat from organisms • Plants • Convert solar energy to chemical energy • Total energy does not change • Sunlight energy is equal to the organic energy created + dissipated heat

21. 2nd law of thermodynamics • Entropy: every energy transfer or transformation increases the disorder of the universe • Note: although order can increase locally (ex: photosynthesis, cleaning your room) there is an unstoppable trend of randomization of the universe as a whole • Allows us to measure efficiency of ecological energy conversions • Ecosystem ecology requires energy flow and material recycling • Sunlight must be continuous as heat is lost to space • Chemical elements must be continually recycled as they are finite

22. Energy flow through ecosystems

23. Food Chains & Food Webs

24. Trophic Levels • Trophic level – each step in the transfer of energy in a community • Producer • Consumer • Decomposer

25. Trophic Levels (cont) • Producers – make food for the community • Autotrophs: make their own food via photosynthesis; plants • Consumers – eat other organisms in the community • Heterotrophs: organisms that cannot make their own food such as animals, and fungi

26. Trophic Levels (cont) • Consumers • Scavengers: feed on dead organisms • Herbivores: eat only plants • Carnivores: eat only animals • Omnivores: eat both plants and animals • Decomposers – organisms that break down the matter of dead organisms into simple nutrients that can be reused • Bacteria; Fungi

27. What limits the length of food chains? • Energetic hypothesis • Food chain is limited due to the inefficiency of energy transfers along the chain. • Does this mean that food chains are longer in areas with more photosynthetic productivity? • Dynamic stability hypothesis • Longer food chains recover much slower form environmental set-backs (ex: extreme winters) • Top predators get hit the hardest

28. What’s biodiveristy and who cares? • The variety of different kinds of organisms as measured by: • Species richness: total # of species • Relative abundance: how many of each species • Having a variety of organisms help to ensure long lasting communities and ecosystems.

29. Human disturbances • Biomagnification • DDT or other pollutant chemicals build up at higher trophic levels • Greenhouse gasses • Traps heat that would otherwise escape … CO2, H20 vapor • Ozone depletion (O3) • Absorbs UV radiation • Depletion is caused by chlorofluorocarbons (CFC’s) • Acid rain • Lowes pH of aquatic ecosystems • Some keystone species are less acid-tolerant • Soil chemistry is disrupted • Calcium (Ca+) and other cations leech from the soil • Desertification • Inability to retain water limits plant growth • Deforestation • Removal of large number of trees

30. Conservation biology tries to ensure • Genetic Diversity • Allows for natural selection due to individual variation • Species Diversity • Allows for a variety of populations • Ecosystem Diversity • Allows for biosphere energy flow and chemical cycling