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Biological Communities

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Presentation on theme: "Biological Communities"— Presentation transcript:

1 Biological Communities
Chapter 18

2 18-1 How Organisms Interact in Communities
Objectives Identify the distinguishing features of symbiotic relationships SCS: B-6.1

3 Species Evolve in Response to each other
Interactions among species Insects/flowers Coevolution Predator/Prey relationships Predation is when one organism feeds on another

4 Symbiosis When two or more species live together in a close, long-term association.

5 Parasitism – when one organism feeds on and usually live on or in another
Example: Ticks and dogs Ticks benefit, but dogs do not

6 Mutualism – a symbiotic relationship in which both benefit from the relationship
Example: flowers and bees Flowers are pollinated and bees have food

7 Commensalism – a relationship in which one organism benefits and the other neither is benefits or is harmed Example: Spanish moss and trees Trees are not hurt nor benefit, but the moss benefits from additional sunlight

8 18-2 How Competition Shapes Communities
Objectives Describe the role of competition in shaping the nature of communities Distinguish between fundamental and realized niches Describe how competition affects an ecosystem Summarize the importance of biodiversity SCS: B-6.1, 6.2

9 Common Use of Scarce Resources leads to competition
Organisms compete for food, space, light, minerals, and water Resources must be in short supply if competition occurs Competition can limit how species use resources Competition can lead to extinction or elimination of a species

10 Niche – the role of a species in a ecosystem
How does the organism affect the environment If niches overlap it may cause competition Niches can vary in size

11 Predation can lesson competition
Eliminates those species less adaptive Promotes biodiversity

12 18-3 Major Biological Communities
Objectives Recognize the role of climate in determining the nature of biological communities Describe how elevation and latitude affect the distribution of biomes Summarize the key features of the Earth’s major biomes SCS: B-6.1, 6.2

13 Climate determines where species lives
Climate is the prevailing weather conditions of an area Temperature and moisture Temperature and moisture determine biological communities

14 Types of Terrestrial Biomes
Tundra Taiga Desert Grassland Temperate Forests Tropical Rain Forests


16 Tundra extremely short growing season (6 to 10 weeks)
long, cold, dark winters (6 to 10 months with mean monthly temperatures below 32° F or 0° C.) low precipitation (less than five inches/year) Animals and animals: Musk ox, artic hare and fox, permafrost (permanently frozen ground)


18 Taiga Long, severe winters and short summers (50 to 100 frost-free days) are characteristic, as is a wide range of temperatures between the lows of winter and highs of summer. Mean annual precipitation is 15 to 20 inches, but low evaporation rates make this a humid climate. Vegetation and Animals: Conifers, beaver, lynx, deer, sparrows…..


20 Deserts Temperature: Average of 38°C (day), average of -3.9°C (night)
 Precipitation: About 250 mm of rain per year  Vegetation: Cacti, small bushes, short grasses  Animals in the desert: coyotes, lizards and snakes, insects, and even some birds) are adapted for burrowing to escape the scorching heat of the desert sun


22 Grasslands Temperature: Dependent on latitude, yearly range can be between -20°C to 30°C   Precipitation: About 500 to 900 mm of rain per year   Vegetation: Grasses (prairie clover, salvia, oats, wheat, barley, coneflowers) Animals: bison and antelope


24 Temperate Forests Temperature: -30°C to 30°C, yearly average is 10°C, hot summers, cold winters   Precipitation: 750 to 1,500 mm of rain per year   Vegetation: Broadleaf trees (oaks, maples, beeches), shrubs, perennial herbs, and mosses Animals: Deer, raccoons, and salamanders are characteristic inhabitants.


26 Tropical Rain Forest Temperature: 20°C to 25°C, must remain warm and frost-free  Precipitation: 2,000 to 10,000 millimeters of rain per year  Vegetation: Vines, palm trees, orchids, ferns Animals and plants: monkeys, cat like mammals, reptiles, insects, diverse flowers, hard wood trees, and medicinal plants


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