Ecology

1. Ecology “Biological Systems interact and these systems and their interactions possess complex properties”

2. Introduction to Ecology • Ecology can be studied at a variety of levels…

3. Inheritance Influences Behavior • Behavior is any action that can be observed and described. • The nature versus nurture question asks to what extent both our genes (nature) and environmental influences (nurture) affect behavior.

4. Study: Love bird nest-making • How do love birds make nests? • Experimental Observations: • Fischer Lovebirds cut long strips leaves and carry the strips with their beaks • Peach-Faced lovebirds cut short strips of leaves and carry strips in back feathers • Hybrid lovebirds have difficulties because they cut medium sized strips and try unsuccessfully to carry strips in their back feathers • Conclusions??

5. Study: Garter Snake food preference • Coastal snakes typically eat slugs in the wild, eat slugs in the lab • Inland snakes typically eat frogs and fish, don’t eat slugs in the lab • Hybrid snakes have an intermediate incidence of “slug acceptance” • Tongue-flicking shows prey recognition • When newborns are presented with cotton swabs covered in slug juice, what happens? • Conclusions?

6. Study: Garter Snake food preference

7. Study: Human Twins • Twins separated at birth and throughout childhood often have similar food preferences, activity patterns, and select similar mates! • Conclusions?

8. Conclusions: • The studies on Love Birds, Garter Snakes, and Humans SUGGEST behavior has a genetic bases • Do these studies DEMONSTRATE that behavior has a genetic basis?

9. Study: Marine Snail and Egg laying behavior • After copulation, snails extrude long strings with more than a million eggs that are then put into the snails’ mouth, covered with mucus, and wound into an irregular mass that is attached to a rock • Researchers isolated gene for Egg Laying Hormone (ELH) and noticed that it forms a string of 271 amino acids while ELH only has 36 amino acids. The gene could be responsible for more than just ELH! • Conclusions?

10. Study: Maternal Behavior in Mice • Maternal instinct hard-wired? • Mice with gene fosB were found to actively synthesize a particular protein after childbirth • fosB mice were seen cuddling with their newborns • Mice without gene fosB did not have the protein • Mice without fosB did not show maternal nurturing behaviors • Conclusions?

11. Conclusions: • Genetics do influence Behavior (“Nature”) • But what about Environment (“Nurture”)?

12. Environmental Impact on Behavior: Learning • Fixed action patterns (FAPs) were believed to be behaviors that were always performed the same way, and they were elicited by a signstimulus. • Many behaviors formerly thought to be fixed action patterns are found to have developed after practice. • Learning is defined as a durable change in behavior brought about by experience. • Deer grazing on the side of a busy highway, oblivious to traffic, is an example of habituation.

13. Instinct and Learning • Laughing gull chicks beg food from parents by pecking at the parents’ beaks • Researchers tried to figure out if this behavior was pure instinct or also learned • The chicks first peck at any beak model; later they only peck at models resembling the parents.

14. Pecking behavior in gulls, FAP?

15. Imprinting • Imprinting, another form of learning, involves a sensitive period. • Chicks, ducklings, and goslings follow the first moving object they see after hatching (usually their mother). • A sensitive period is the only period during which a particular behavior such as imprinting, develops.

16. Associative Learning • Classical Conditioning • If paired stimuli presented consistently to produce response, over time one stimulus alone will produce the desired response • This suggests that an organism can be trained (conditioned) to associate any response with any stimulus. • Unconditioned responses are those that occur naturally; conditioned responses are those that are learned.

18. Associative Learning • Operant Conditioning • In operant conditioning, a stimulus-response connection is strengthened. • This resulted from reinforcing a particular behavior. • Skinner came up with Behaviorism based on his experiments that used operant conditioning

20. Orientation and Migration Ability to navigate

21. Cognitive learning • Learning through observation, imitation, and insight • Insight learning: animal solves a problem it does not have experience with

22. Animal Communication • Communication is an action by a sender that influences the behavior of a receiver. • When the sender and receiver are members of the same species, signals will benefit both the sender and the receiver.

23. Animal Communication • Chemical Communication • These signals are chemicals (e.g., pheromones, urine, and feces) and have the advantage of working both night and day. • A pheromone is a chemical released to cause a predictable reaction of another member of the same species.

24. Aphids responding to alarm pheromones

25. Auditory Communication • Advantages • Faster • Effective night and day • Modified by loudness, pattern, duration, and repetition

26. Whale Song

27. Visual Communication • Visually communicate intensions- no need for chemical signal • During the day • Fighting/Defense and Courtship Displays

28. Courtship display

29. Tactile Communication • When one animal touches another to impart information of some sort

30. Can Behavior Increase Fitness? • Behavioral Ecology assumes behavior is subject to natural selection i.e. really dangerous/stupid behavior will lead to less reproductive success • Examine: • Territoriality • Reproductive Strategies • Social Behavior/Society • Altruism

31. Territoriality: Increased Fitness? • Territory: animal’s home range • Territoriality: defending the home range • Defense could be dangerous if fighting occurs and certainly uses a lot of energy

32. Territoriality Increased Fitness?Group territoriality and the benefits of sociality in the African lion, Pantheraleo • 38 years of data on 46 lion prides in the Serengeti National Park, Tanzania • Observed effects of territoriality on fitness of both females and males • Say-Mean-Matter activity

35. Different Reproductive Strategies • Some animals, such as gibbons, are monogamous; they pair bond, and both male and female help with the rearing of the young. • Most other primates are polygamous; males monopolize multiple females. • A limited number of primates are polyandrous. • Tamarins live together in groups of one or more families in which one female mates with more than one male.

36. Monogamous: African Antelope Polygamous: Hyenas (although matriarchal) Polyandrous: Bees with their queen

37. Sexual Selection  Increased Fitness? • Sexual selection refers to adaptive changes in males and females that lead to an increased ability to secure a mate • In males, this may result in an increased ability to compete with other males for a mate. • Females may select a mate with the best fitness (ability to produce surviving offspring), thereby increasing her own fitness.

38. Societies  Increase Fitness? • Benefits: avoid predators, raise young, find food • Costs: disagreements, individuals may be disadvantaged because of their group affiliation, parasites/disease spread more effectively • Cost/Benefit analysis, is it worth it?

39. Altruism vs. Self Interest • Altruism: behavior that potentially decreases fitness of one individual while increasing another’s fitness • Inclusive fitness: fitness of individual and close relatives • Indirect vs. Direct selection • Reciprocal Altruism: short term sacrifice to potentially increase future reproductive success • Ex. Birds who help parents raise future generations

40. Foraging and Fitness • Foraging for food (gathering food) can obviously increase fitness • Benefitss during foraging behavior must outweigh risks • Optimal foraging model: natural selection will effect foraging behavior so it is as energetically efficient as possible

41. Foraging Example