chapter 8
Download
Skip this Video
Download Presentation
Chapter 8

Loading in 2 Seconds...

play fullscreen
1 / 42

Chapter 8 - PowerPoint PPT Presentation


  • 241 Views
  • Uploaded on

Community Structure – spatial arrangement of its individuals and populations. Chapter 8. Community Characteristics. Physical Appearance – relative size, stratification and distribution of its populations and species Species Diversity – number of species

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Chapter 8' - LionelDale


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
community characteristics
Community Characteristics
  • Physical Appearance – relative size, stratification and distribution of its populations and species
  • Species Diversity – number of species
  • Species Abundance – numbers of each species
  • Niche Structure – number of ecological niches and how they interact
biodiversity
Biodiversity
  • Species Diversity – variety of different species
  • Genetic Diversity – variability among individuals within a species
  • Ecological Diversity – variability of ecosystems
most biodiversity
Most Biodiversity
  • Tropical Rain Forests
  • Coral Reefs
  • Deep Sea
  • Large Tropical Lakes
factors affecting species diversity
Factors Affecting Species Diversity
  • Latitude
  • Depth (in aquatic) – species diversity increases from surface to about 2,000 m
slide6

© 2004 Brooks/Cole – Thomson Learning

25

25

Snails

Tube worms

20

20

15

15

Species diversity

10

10

5

5

Coast

Deep Sea

Coast

Deep Sea

0

0

0

2,000

4,000

6,000

0

2,000

4,000

6,000

Depth (meters)

Depth (meters)

factors affecting species diversity7
Factors Affecting Species Diversity
  • Pollution (in aquatic) – decrease in diversity and abundance because pollution
species diversity increases with
Species diversity increases with….
  • Increasing solar radiation
  • Increasing precipitation
  • Decreasing elevation
  • Pronounced seasonal variations
species equilibrium model
Species Equilibrium Model
  • The number of species found on an island depends on:
  • The rate at which new species immigrate to the island
  • The rate at which species become extinct on the island
  • At some point they reach an equilibrium that determines the island’s average number of different species
slide10

© 2004 Brooks/Cole – Thomson Learning

High

Rate of immigration

or extinction

Low

Equilibrium number

Number of species on island

(a)

Immigration and extinction rates

smaller island has lower diversity because
Smaller island has lower diversity because…
  • Smaller target for potential colonizers
  • Smaller islands have higher extinction rates because they have fewer resources and less diverse habitats for colonizing species
slide13
For islands of equal size – the island closest to the mainland will have the higher immigration rate and thus higher diversity
slide14

© 2004 Brooks/Cole – Thomson Learning

High

Rate of immigration

or extinction

Low

Small island

Large island

Number of species on island

(b)

Effect of island size

slide15

© 2004 Brooks/Cole – Thomson Learning

High

Rate of immigration

or extinction

Low

Far island

Near island

Number of species on island

(c)

Effect of distance from mainland

types of species
Types of Species
  • Native Species – species that normally live and thrive in a particular ecosystem
  • Nonnative Species – (invasive species or alien species) species that migrate into an ecosystem or are deliberately or accidentally introduced
  • Indicator Species – species that serve as early warnings of damage to a community or ecosystem
types continued
Types - continued
  • Keystone Species – species that play a pivotal role in the structure and function of an ecosystem because of their strong interactions with other species and the fact that they process material out of proportion to their numbers or biomass.
how do species interact
How Do Species Interact?
  • Intraspecific competition – competition between members of the same species
  • Interspecific competition – competition between members of two or more different species for food, space or any other limited resource.
interspecific competition
Interspecific Competition
  • Interference competition – a species limits another’s access to some resource.
  • Exploitation competition – species have roughly equal access to a specific resource but differ in how fast or efficiently they exploit it
competitive exclusion principle
Competitive Exclusion Principle
  • Species cannot occupy the same ecological niche indefinitely.
slide21

High

Relative population density

Low

0

2

4

6

8

10

12

14

16

18

Days

Each species grown alone

Paramecium

aurelia

Paramecium

caudatum

slide22

High

Paramecium

aurelia

Relative population density

Paramecium

caudatum

Low

0

2

4

6

8

10

12

14

16

18

Days

Both species grown together

resource partitioning
Resource Partitioning
  • Species that compete for the same resources evolve adaptations that reduce or avoid competition or an overlap of their fundamental niches.
predator prey interactions
Predator - Prey Interactions
  • Predation – members of one species (predator) feed directly on all or part of a living organism of another species (prey)
slide26

Bombardier beetle

Span worm

Wandering leaf insect

Foul-tasting monarch

butterfly

When touched, the

snake caterpillar

changes shape to look

like the head of a snake

Poison dart frog

Viceroy butterfly mimics

monarch butterfly

Hind wings of io moth

resemble eyes of a

much larger animal

symbiosis
Symbiosis
  • A relationship in which species live together in an intimate association. There are three types of symbiosis
three types of symbiosis
Three types of symbiosis
  • Parasitism – one species (the parasite) feeds on part of another organism (the host) by living on or in the host. Examples include: tapeworms, fleas, ticks, mosquitoes, mistletoe plants and fungi
slide29
Mutualism – two species involved in a relationship interact in ways that benefit both.
  • Benefits include: having pollen and seeds spread; being supplied with food, or receiving protection
  • Examples include: mycorrhizae that live in plant roots; bacteria in the digestive tracts of animals; birds on the backs of black rhinos that remove insects
slide31
Commensalism – a relationship in which one species benefits but the other is neither harmed nor helped.
  • Examples include: redwood sorrel which grows in the shade of redwood trees; epiphytes which attach themselves to the branches of large trees.
ecological succession
Ecological Succession
  • The gradual change in species composition in response to changing environmental conditions.
  • Two types: primary and secondary
  • Primary is the gradual establishment of biotic communities on bare rock
  • Secondary is the reestablishment of biotic communities
pioneer species
Pioneer Species
  • Before a community of plants can become established there must be soil present
  • Depending on the climate, it can take several hundred to several thousand years to produce fertile soil
  • Soil formation begins when pioneer species attach themselves to rock (lichens and mosses)
slide34
Pioneer species are replaced by small perennial grasses and herbs (ferns in the tropics)
  • These are early successional plant species
  • These grow close to the ground, have short lives and can establish large populations quickly
slide35
Mid successional plant species – herbs, grasses and low shrubs.
  • These are replaced by trees that are adapted to lots of sunlight
  • Late successional plant species – (mostly trees) that can handle shade
slide36

Mature oak-hickory forest

Young pine forest

Shrubs

Perennial

weeds and

grasses

Annual

weeds

Time

secondary succession
Secondary Succession
  • Begins in an area where the natural community has been disturbed, removed or destroyed
  • Examples include abandoned farms, burned forests, polluted streams, flooded land
factors affecting succession
Factors Affecting Succession
  • Facilitation – one set of species makes an area suitable for species with different niche requirements
  • Inhibition – an early species hinders the establishment and growth of other species
  • Tolerance – late successional plants are unaffected by plants at earlier stages of succession
slide39
A disturbance to an ecosystem can convert a particular stage of succession to an earlier stage
  • Types of disturbances: habitat destruction, fire, flooding, drought, landslide, stream alteration, etc…
slide40
Ecosystems are continually changing
  • Cannot predict the course of a given succession
  • Cannot view it as preordained progress toward an ideally adapted climax community
stability
Stability
  • All living systems contain feedback loops (positive and negative) that interact to provide some stability over each system’s expected life span
  • This stability is maintained by constant dynamic change in response to changing environmental conditions
ecosystem stability
Ecosystem Stability
  • Inertia or persistence – the ability of a living system to resist being disturbed or altered
  • Constancy – ability of a living system to keep its numbers within the limits imposed by the available resources
  • Resilience – ability of a system to bounce back after a disturbance (not drastic)
ad