Species Interactions Chapter 8, Sections 2

1. Species InteractionsChapter 8, Sections 2

2. Populations are limited Limiting Factors : things in the environment that keep a population from growing out of control

3. Limiting factors Density-independent limiting factors • These are not dependent on the size of the population • Examples: natural disasters, weather, human destruction of habitat

4. Limiting factors Density-dependent limiting factors Effects of these depend on the size of the population Examples: • disease Tasmanian devil population threatened by contagious disease called devil facial tumor disease

5. Limiting factors Density-dependent limiting factors Example: Species Interactions • Competition • Predation • Symbiosis

6. Niche Definition: the role of a species within an ecosystem Not just the habitat, but how it interacts with other organisms, too

7. Competition Definition: when two or more individuals or populations try to use the same limited resource Both are negatively affected by the interaction

8. Types of competition • Interspecific competition – competition between members of different species Example: plants compete for limited nutrients in the soil around them, light, water, space, etc.

9. Interspecific competition Organisms have different adaptations to improve competitive edge – a few examples: • produce many offspring • have extensive root systems that are efficient • extremely fast growth rate • allelopathy – when a plant produces a chemical that prevents other plants from growing around it (black walnut, sunflowers, junipers) • aggressive behavior

10. Interspecific competition Example: warblers – different species of small songbirds that are similar in habit, compete for the same resources in trees Bay-breasted warbler Yellow-rumped warbler Cape May warbler

11. Niche partitioning Reduces interspecific competition by spatially dividing up resources

12. Niche partitioning Due to competition, each species uses less of the niche than they are capable of using Example: barnacles on p. 205

13. Types of competition • Intraspecific competition – members of the same species compete for food, mates, nesting sites, space, water, etc. Example: Wolves fighting for meat Alpha male will eat first

14. Survival of the Fittest Intraspecific competition can also be called “survival of the fittest” and is a driving force of evolution The individual that is best adapted to outcompete the others will survive and pass on its traits to its offspring

15. Predation Type of species interaction in which one organism (predator) feeds on another (prey)

16. Predator/Prey relationships Does the predator control the prey, or does the prey control the predator?

17. Predator/Prey relationships Many adaptations have evolved due to predator/prey relationships Examples of adaptations of prey: camouflage, warning coloration, mimicry, chemical warfare, behavior

18. Camouflage: Hide Butterfly that resembles a dead leaf

19. Warning Coloration: Advertise that you are not tasty Bright colors advertise the fact that a prey is distasteful or poisonous Ex: bees, poison arrow frogs, coral snake

20. Behavior: Act tough and hang around with your friends Flocking and mobbing by birds – safety in numbers

21. Mimicry: Look like someone else Batesian mimicry – when one palatable species mimics another that is harmful or distasteful Ex: insects mimic wasps Right: A and B are stinging wasps, C-E are flies that mimic the wasps, F is a beetle that mimics the wasps

22. Mimicry Mullerian mimicry – when two or more species look alike and both are unpalatable, both benefit from the reinforcement to predators to avoid the pattern seen Ex: Viceroy and Monarch are BOTH unpalatable Monarch Viceroy Bluejay eats a monarch, then vomits, learns not to eat them

23. Combination: Mimicry and behavior Butterfly with fake eyes on wings

24. Urban mimicry http://www.worth1000.com/contest.asp?contest_id=9307&display=photoshop

25. Urban mimicry http://www.worth1000.com/contest.asp?contest_id=9307&display=photoshop

26. Predation Examples of adaptations of predators: • Adaptations for capture - pursuit - ambush - trap - tools • Adaptations for killing - bite/claw - suffocate - poison

27. Symbiosis • Means “living together” • Three types….

28. Symbiosis • Parasitism – the parasite lives on or in the host • Parasite benefits, host is harmed but not usually killed (this is different from predation where the prey is killed) Adult deer tick on a person Wasp larvae living off a tomato hornworm

29. Parasitism Two categories when parasite lives on/in host: • internal (e.g., tapeworms) • external (e.g., ticks, fleas) Some parasites never come in contact with their hosts (e.g., cowbirds lay eggs in other birds’ nests and leave young to be raised by them)

30. Symbiosis Benefit to clown fish: protection, eats food caught by anemone’s stinging cells Benefit to anemone: clown fish keeps anemone cleans, provides nutrients in wastes, circulates water • Mutualism – both species benefit from the relationship Flowers and their pollinators both benefit as pollinators eat pollen and distribute it to other plants

31. Mutualism Pollination mutualism – animals (bees, hummingbirds, butterflies) get food and plant gets pollen distributed directly to the right plant Nutritional mutualism – e.g., lichens – algae (provides food) plus fungus (provides structure and absorption of nutrients, water) Gut inhabitant mutualism – bacteria in termites’ gut or in humans’ gut help with digestion, get food

32. Mutualism – lichens are made of fungus and algae, both benefit • Fungus: able to absorb water and nutrients from surface material • Algae: carries out photosynthesis to make food (sugars)

33. Symbiosis • Commensalism – one species benefits, the other is neither hurt nor helped Cattle egrets eat insects in the grass that are stirred up by the cattle Cattle aren’t hurt or helped (but egrets may pick off a few parasites)

34. Commensalism • Example: epiphytes – plants that live on other plants but do not hurt them Resurrection fern Tropical orchids

35. Coevolution Definition: process in which two species in a close relationship evolve in response to each other, usually to the benefit of one or both species Example: plants and pollinators have adaptations that help them in the relationship

36. Coevolution: Adaptations of pollinators • Butterfly tongue • Hummingbird beak

37. Coevolution: Adaptations of plants • The flowers of Potentillaanserina prominently exhibit UV-meditated flower marks to aid visiting pollinators to reach their target.