Biological Biological CommunitiesCommunitiesChapter 18Chapter 18

18-1 How Organisms 18-1 How Organisms Interact in CommunitiesInteract in Communities

ObjectivesObjectives Identify the distinguishing features of Identify the distinguishing features of

symbiotic relationshipssymbiotic relationships

SCS: B-6.1SCS: B-6.1

Species Evolve in Species Evolve in Response to each otherResponse to each other

Interactions among speciesInteractions among species Insects/flowersInsects/flowers CoevolutionCoevolution

Predator/Prey relationshipsPredator/Prey relationships Predation is when one organism feeds on Predation is when one organism feeds on

anotheranother

SymbiosisSymbiosis When two or more species live together in a When two or more species live together in a

close, long-term association.close, long-term association.

ParasitismParasitism – when one organism feeds on – when one organism feeds on and usually live on or in anotherand usually live on or in another

Example: Ticks and dogsExample: Ticks and dogs

Ticks benefit, but dogs do not Ticks benefit, but dogs do not

MutualismMutualism – a symbiotic relationship in – a symbiotic relationship in which both benefit from the relationshipwhich both benefit from the relationship

Example: flowers and beesExample: flowers and bees

Flowers are pollinated and bees have foodFlowers are pollinated and bees have food

CommensalismCommensalism – a relationship in which – a relationship in which one organism benefits and the other one organism benefits and the other neither is benefits or is harmedneither is benefits or is harmed

Example: Spanish moss and treesExample: Spanish moss and trees

Trees are not hurt nor benefit, but the moss Trees are not hurt nor benefit, but the moss benefits from additional sunlightbenefits from additional sunlight

18-2 How Competition 18-2 How Competition Shapes CommunitiesShapes Communities

ObjectivesObjectives Describe the role of competition in shaping the Describe the role of competition in shaping the

nature of communitiesnature of communities Distinguish between fundamental and realized Distinguish between fundamental and realized

nichesniches Describe how competition affects an Describe how competition affects an

ecosystemecosystem Summarize the importance of biodiversitySummarize the importance of biodiversitySCS: B-6.1, 6.2SCS: B-6.1, 6.2

Common Use of Scarce Resources leads Common Use of Scarce Resources leads to competitionto competition Organisms compete for food, space, light, Organisms compete for food, space, light,

minerals, and waterminerals, and water Resources must be in short supply if Resources must be in short supply if

competition occurscompetition occurs Competition can limit how species use Competition can limit how species use

resourcesresources Competition can lead to extinction or Competition can lead to extinction or

elimination of a specieselimination of a species

NicheNiche – the role of a species in a – the role of a species in a ecosystemecosystem How does the organism affect the How does the organism affect the

environmentenvironment If niches overlap it may cause competitionIf niches overlap it may cause competition Niches can vary in sizeNiches can vary in size

Predation can lesson competitionPredation can lesson competition Eliminates those species less adaptiveEliminates those species less adaptive Promotes biodiversityPromotes biodiversity

18-3 Major Biological 18-3 Major Biological CommunitiesCommunities

ObjectivesObjectives Recognize the role of climate in determining Recognize the role of climate in determining

the nature of biological communitiesthe nature of biological communities Describe how elevation and latitude affect the Describe how elevation and latitude affect the

distribution of biomesdistribution of biomes Summarize the key features of the Earth’s Summarize the key features of the Earth’s

major biomesmajor biomes

SCS: B-6.1, 6.2SCS: B-6.1, 6.2

Climate determines where species livesClimate determines where species lives Climate is the prevailing weather conditions Climate is the prevailing weather conditions

of an areaof an area Temperature and moistureTemperature and moisture Temperature and moisture determine biological Temperature and moisture determine biological

communitiescommunities

Types of Terrestrial Types of Terrestrial BiomesBiomes

TundraTundra TaigaTaiga DesertDesert GrasslandGrassland Temperate ForestsTemperate Forests Tropical Rain ForestsTropical Rain Forests

TundraTundra

extremely short growing season (6 to 10 extremely short growing season (6 to 10 weeks) weeks)

long, cold, dark winters (6 to 10 months with long, cold, dark winters (6 to 10 months with mean monthly temperatures below 32° F or 0° mean monthly temperatures below 32° F or 0° C.) C.)

low precipitation (less than five inches/year)low precipitation (less than five inches/year) Animals and animals: Musk ox, artic hare and Animals and animals: Musk ox, artic hare and

fox, fox, permafrost permafrost (permanently frozen ground)(permanently frozen ground)

TaigaTaiga

Long, severe winters and short summers (50 Long, severe winters and short summers (50 to 100 frost-free days) are characteristic, as to 100 frost-free days) are characteristic, as is a wide range of temperatures between the is a wide range of temperatures between the lows of winter and highs of summer.lows of winter and highs of summer.

Mean annual precipitation is 15 to 20 Mean annual precipitation is 15 to 20 inches, but low evaporation rates make this inches, but low evaporation rates make this a humid climate. a humid climate.

Vegetation and Animals: Conifers, beaver, Vegetation and Animals: Conifers, beaver, lynx, deer, sparrows…..lynx, deer, sparrows…..

DesertsDeserts

Temperature: Temperature: Average of 38°C (day), average of -Average of 38°C (day), average of -3.9°C (night) 3.9°C (night)

  Precipitation: Precipitation: About 250 mm of rain per year About 250 mm of rain per year

  Vegetation: Vegetation: Cacti, small bushes, short grasses Cacti, small bushes, short grasses

  Animals in the desert: coyotes, lizards and snakes, Animals in the desert: coyotes, lizards and snakes, insects, and even some birds) are adapted for insects, and even some birds) are adapted for burrowing to escape the scorching heat of the desert burrowing to escape the scorching heat of the desert sun sun

GrasslandsGrasslands Temperature: Temperature: Dependent on latitude, Dependent on latitude,

yearly range can be between -20°C to 30°C yearly range can be between -20°C to 30°C   

Precipitation: Precipitation: About 500 to 900 mm of rain About 500 to 900 mm of rain per year per year   

Vegetation: Vegetation: Grasses (prairie clover, salvia, Grasses (prairie clover, salvia, oats, wheat, barley, coneflowers) oats, wheat, barley, coneflowers)

Animals: bison and antelope Animals: bison and antelope

Temperate ForestsTemperate Forests Temperature: Temperature: -30°C to 30°C, yearly average is -30°C to 30°C, yearly average is

10°C, hot summers, cold winters 10°C, hot summers, cold winters   

Precipitation: Precipitation: 750 to 1,500 mm of rain per year 750 to 1,500 mm of rain per year   

Vegetation: Vegetation: Broadleaf trees (oaks, maples, Broadleaf trees (oaks, maples, beeches), shrubs, perennial herbs, and mosses beeches), shrubs, perennial herbs, and mosses

Animals: Deer, raccoons, and salamanders are Animals: Deer, raccoons, and salamanders are characteristic inhabitants. characteristic inhabitants.

Tropical Rain ForestTropical Rain Forest

Temperature: Temperature: 20°C to 25°C, must remain warm and 20°C to 25°C, must remain warm and frost-free frost-free

  Precipitation: Precipitation: 2,000 to 10,000 millimeters of rain per 2,000 to 10,000 millimeters of rain per year year

  Vegetation: Vegetation: Vines, palm trees, orchids, ferns Vines, palm trees, orchids, ferns

Animals and plants: monkeys, cat like mammals, Animals and plants: monkeys, cat like mammals, reptiles, insects, diverse flowers, hard wood trees, and reptiles, insects, diverse flowers, hard wood trees, and medicinal plants medicinal plants