Ecology A Study of Relationships

Size: px
Start display at page:

Download "Ecology A Study of Relationships"

Transcription

1 Habitat a Place to call Home biotic living abiotic nonliving living things depend on both to survive species of plants depend on chemical and physical conditions to exist soil type, temperature, water, etc... species of animals depend on the available plant life to survive food habitat: the place in an ecosystem where an organism prefers to live Cover: places where an animal can seek refuge from threats. Changes in habitat and cover in an ecosystem can be produced both by natural and human activities Brewer 1

2 Populations of Woodpeckers Similar organisms that breed to produce fertile offspring are members of the same species Example: 20 different species of woodpeckers exist in North America Population: the total number of a species living in a defined region term may apply to any living thing Example: A forest includes a population of hairy and downy woodpeckers, as well as various populations of different species of plants and animals. Both hairy and downy woodpeckers are cavity nesters birds who build their nest in the holes of trees. Brewer 2

3 Hairy Downy Habitat forest interior forest edge Beak long short Brewer 3

4 More Cavities Needed Bluebirds are cavity nesters the fields and orchards of early settlers increased habitat insect feeding on abundant fields and meadows by 1969 less than 100 bluebirds nesting in Minnesota 90% decline between 1935 and 1985 Why? Brewer 4

5 More Cavities Needed Factors for bluebird decline insecticides loss of habitat Solutions? cavities in wooden fence posts replaced with steel fence posts after WWII. development of highways, shopping malls, residential areas, etc... all dramatically decreased habitat competition with other species (sparrows) for available insects and nesting Brewer 5

6 More Cavities Needed Solutions The North American Bird Society's efforts bird houses can be used to aid the recovery of many other species Brewer 6

7 Finding the Right Neighborhood Prior to settlement of America, most of the area east of the Mississippi River was heavily wooded. clearing of land by people created a habitat for rabbits, grouse, and deer settlers also killed predators that normally hunted these animals population of these species increased due to these factors Brewer 7

8 Do Not Disturb Habitat fragmentation: the breaking of habitats into smaller isolated pieces. Causes: agriculture urban development construction of roads pipelines power lines etc... Brewer 8

9 Do Not Disturb Habitat fragmentation especially affects animals that need large habitats Edges are created from fragmentation; many animals cannot survive due to the disturbances The most critical threat to animals and plants today is habitat destruction. Brewer 9

10 Limits to Population Growth carrying capacity: the maximum size of a population existing in the ecosystem with damage to the ecosystem limiting factors: factors that prevents the growth of a population Space the need for territories emigration: leaving an area when the population becomes too crowded Example: lemmings Brewer 10

11 Food organisms that specialize in eating only one type of food are especially susceptible Brewer 11

12 Climate and Weather temperature and precipitation affect population growth Cover hiding places for prey species Brewer 12

13 Disease As population density increases, incidence of disease increases the effect of overcrowding Brewer 13

14 Human activity pollution (atmospheric, hydrological, light, sound, etc...) interferes with many species breeding may depend on availability of habitat without human disturbances Shade Canopy: habitat composed of the shaded tops of mature trees. hardwood treetops like live oak limit the growth of other trees of the same species, as well as others. Brewer 14

15 Population Explosions occur when limiting factors are removed the rabbits of Australia white tail deer Brewer 15