Ecological Interactions in Habitats: Lion in the Plains of Africa

1. Chapter 14 Ecological Interactions

2. Habitat • All of the biotic and abiotic factors in the area where an organism lives. • Including: • Grass • Trees • Watering holes • What would the habitat for a lion in the plains of Africa look like?

3. Ecological Niche • An organisms habitat is its address, its niche is its occupation. • Full range of physical, chemical and biological conditions in which it lives and the way the organism uses these conditions. • A niche is how the organism lives within its habitat. • It includes: • Food: Type of food it eats, how it obtains food, what other species use the organism as food. • Abiotic Conditions: Temperature and amount of water a species can tolerate. • Behavior: Time of day a species is active as well as where and when it reproduces.

4. CompetitiveExclusion • Ability for an organism to survive and reproduce is driven by natural selection. • Species can share similar habitats and use some of the same resources, but not in the same way. • One species will always be better adapted to the environment. • Competitive exclusion- when two species compete for resources, one will be better suited, and the other will be pushed into another niche or become extinct. • Resource- necessity of life. • Example: Bee and butterfly • Lion King Video

5. Other outcomes of competitive Exclusion • Niche Partitioning- Two species could naturally divide resources based on competitive advantages. • Two squirrels: One type ate nuts from the tops of trees, while others ate nuts from the ground. • Niche is divided. • Evolutionary response- Species could experience divergent evolution. • Two Squirrels: Selection for larger teeth allowed one type to crack larger nuts. Selection for small teeth allowed the other to eat small seeds. • Both eat and survive because they are not competing for the same resource.

6. Ecological Equivalents • Species that occupy similar niches but live in different geographical locations. • Both frogs have brightly colored skin, poison, similar habitat and prey on similar insects. • But NEVER compete for the same resources because they live in different locations.

7. Community Interactions • Competition- when organisms of same or different species attempt to use an ecological resource in the same place andat the same time. • Resource- necessity of life • Interspecific- two different species compete for a limited resource, such as space. • Example: Lawn- Grass, dandelions, and other plants compete for water and nutrients. • Intraspecific- Individuals of the same species struggle for limited resources. • Example: Spring breeding of birds- males will share space with other birds, but not members of its own species. • video

8. Community Interactions • Predation- one organism captures and feeds upon another organism. • Herbivores can also be considered predators to plants!

9. Community Interactions • Symbiosis- “living together in direct contact”. • Mutualism-bothbenefit. • Flowers and insects, Birds eating ticks off cattle • Commensalism- one benefits, other is neither helped nor harmed. • Barnacles on marine animals, Birds eating insects in grass near cattle, Fire ants and acacia tree. • Parasitism- one organism lives on or inside another and harms it. 1 Benefits and the other is harmed. • Video McDougal • Tapeworms, fleas, ticks, lice, leeches

10. Label each ________________ _________________ _________________ Video

11. Changes in Population Size • Population size is usually changing as resources change • If resources increase, population increases. • If resources decrease, population decreases. • Immigration- movement of individuals into a population from another population. Increases population size. • Births – increase population size • Emigration- Movement of individuals out of a population into another population. Decreases population size. • Deaths – decrease population size. • Think of a population of fruit flies that might live in your backpack. Describe how these four factors would influence their population.

12. Types of Population Growth • Exponential Growth- • Under ideal conditions with unlimited resources population size will increase dramatically. • Will start out slow and then approaches an infinitely large size - J curve. • When as species moves into a previously uninhabited area.

13. Types of Population Growth • Logistic Growth • Populations growth will slow or stop after a period of exponential growth. • As resources become less available, the growth of a population slows or stops - S curve . • Reached carrying capacity - number of individuals that a given environment can support.

14. Carrying Capacity & Population Crash • Carrying Capacity- Maximum number of individuals of a particular species that the environment can normally and consistently support. • Carrying capacity can change as the environment changes. • Population Crash- Dramatic decline in the size of a population over a short period of time. • Caused by factors that greatly limit resources. • Harsh winters and scarcity of food.

15. Limits to Growth • Limiting factors cause population growth to decrease. • Density Dependent- only become limiting when a population reaches a certain level (TOO LARGE). 1. Competition for resources – food and shelter. 2. Predation • Population of predator can be limited by available prey. 3. Parasitism 4. Disease • Density Independent- affects populations in same way regardless of size. • Unusual weather • Natural disasters • Seasonal cycles • Human activities

16. Ecological Succession • Sequence of biotic changes that regenerate a damaged community or create a community in a previously uninhabited area. • Predictable changes that occur in a community over time. • Ecosystems are constantly changing in response to natural and human disturbances. • As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further change. • How did Hawaii Form? • Video

17. Ecological Succession • Primary Succession -occurs on surfaces where no soil exists, uninhabited. • Volcanic eruptions, bare rock. • Pioneer species- first species to populate. • Often lichens (fungus and algae), mosses which can break down rock. • When they die they add organic material to become soil. • Video

18. Ecological Succession • Secondary succession – a disturbance changes an existing community without removing soil. Reestablishment of an ecosystem. • There is no end to secondary succession. • Land clearing and farming • Wildfires • Mount St. Helens