Models of Population Growth & Relationships

Transcription

1 Models of Population Growth & Relationships

2 Populations A population is made up of all the member of one species that live in an area. Buffalo herd on Antelope Island (left) Wilson s Phalaropes flying over the Great Salt Lake (right)

3 Population Growth Factors Determining Population Immigration Birth rates Emigration Death rates Population Growth Rate how fast a population changes in size over time Growth rate = (birth rate death rate) + (immigration rate emigration rate)

4 Population Growth How does the amount of space available to each organism affect its interaction with other organisms in the same area? What would happen if the number of students in our classroom doubled? Deer

5 Necessities of Life 1. Food 2. Water 3. Shelter 4. Space Bear River, Utah

6 Limiting Factors: Factors that limit the growth of a population Available Resources Amount of available water Space Shelter Food competition for resources predation disease Red Tailed Hawk Bridge construction on I-84

7 Carrying Capacity The largest number of individuals of one species that an ecosystem can support over time. What happens when a population becomes larger than an ecosystem s carrying capacity? Overcrowding Lack of resources Unhealthy environment Fish don t grow as big Waste might build up faster than it can be broken down

8 Carrying Capacity: How Many Fish Will Your Tank Support? One inch of fish per gallon of tank: 20 gallon tank = 20 inches of fish Overcrowd tank Water quality deteriorates Aggressive behaviors of fish Limiting Factors: Amount of available water Space Shelter Food

9 Community A community is all the populations living in an ecosystem at the same time Tamarisk along Colorado River in Utah

10 Interactions Between Organisms Competition: When two or more organisms compete for the same resource

11 Predator/Prey Great Blue Heron (Ardea herodias) - White Perch (Morone americana) A type of relationship in which one organism consumes all or part of another. A predator is an organism that eats another organism. The prey is the organism which the predator eats. Examples: lion & zebra; fox & rabbit; grasshopper & leaf The Eagle(Predator) swoops down on the rabbit(prey)

12 Symbiosis A close relationship between the individuals of two or more different species. Mutualism: Oxpecker s gain a big, hulking animal as a shield from predation while Rhinoceroses receive a good skin clean Commensalism: Squirrel in tree Parasitism: Tapeworm

13 Mutualism: Both benefit from the relationship alligator and plover Moray and cleaner shrimp A blind bulldozer shrimp and a goby fish: share a dwelling that the shrimp builds fish lets the shrimp know when trouble is coming.

14 Mutualism: Both benefit from the relationship Hummingbirds & Flowers: Pollination is an example of mutualism Yucca and Yucca moth Blanding, Utah Broad-tailed Hummingbird in the Utah canyon lands

15 Commensalism: One benefits from the relationship while the other is unaffected As large grazers move through the grass, they stir up insects. Cattle Egrets follow them and get a banquet Large grazers are neither helped nor harmed by the presence of the birds

16 Commensalism: One benefits from the relationship while the other is unaffected The blue spruce in our front yard is home to a family of quails. They benefit by getting shelter from the tree. The tree is unaffected.

17 Commensalism: One benefits from the relationship while the other is unaffected

18 Parasitism: One is harmed, the other benefits from the relationship Parasitic wasp cocoons on hornworm. Fleas on dogs and cats Bite their hosts and feed on blood. Mosquito & Humans

19 Parasitism: One is harmed, the other benefits from the relationship Dwarf mistletoe grows on a fir at Cedar Breaks. The parasitic plant sections often grow in short, distorted branches. In native Utah forests, dwarf mistletoes attack spruces, firs, junipers and some other trees. Picture by Larry A. Sagers, a horticulture specialist for the Utah State University Extension Service at Thanksgiving Point.