1. Unit 3 Ecology
SB4. Students will assess the dependence of all organisms on one another and the flow of energy and matter within their ecosystem.
a. Investigate relationships among organisms, populations, communities, ecosystems, and biomes.

2. LEQ1: What relationships exist among organisms, populations, communities, ecosystems, and biomes?

3. Relationships
Ecology is the study of relationships among organisms and their environment.
Interactions between living things and their environment
Interactions among living things

4. Relationships
Ecologists study the environments different levels of organization.
Organism
Population
Community
Ecosystem
Biome
Biosphere

5. Relationships
An organism is an individual living thing, such as an alligator.
Species: group of similar organisms that can breed and produce fertile offspring.
Organism
Organism

6. Relationships
A population is a group of the same species that lives in one area.
Population
Population
Organism
Organism

7. Relationships
A community is a group of different species that live together in one area
Community
Community
Population
Population
Organism
Organism

8. Relationships
An ecosystem includes all of the organisms as well as the climate, soil, rocks, water, and other nonliving things in a given area.
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism

9. Relationships
A biome is a major regional or global community if organisms characterized by the climate conditions and plant communities that thrive there.
Biome
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism

10. Relationships
The biosphere contains the combined portions of the planet in which all of life exists.
All biomes (land, water, air)
The entire planet
Biosphere
Biome
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism

11. Ecologist Study Relationships
Observation
Direct Survey
Used for easy to spot species
Indirect Survey
Used for species that are difficult to spot or track
Look for signs of their presence.

12. Relationships Experimentation
Conducted in lab which gives researchers more control
Conducted in the field which is a more accurate account of natural interactions

13. Relationships Modeling
Allows scientists to learn about organisms or ecosystems in ways that would not be possible in a lab or natural setting
Use computer and mathematical models
Ecologists use data transmitted by GPS receivers worn by elephants to develop computer models of the animal’s movements.

14. Biotic and Abiotic Factors
Every ecosystem includes both living and nonliving factors

15. Biotic and Abiotic Factors
Biotic factors are living things.
Plants
Animals
Fungi
Bacteria
Plants

16. Biotic and Abiotic Factors
Abiotic factors are nonliving things
Moisture
Temperature
Wind
Sunlight
soil
Sunlight
Moisture

17. Biotic and Abiotic Factors
Changing one factor is an ecosystem can affect many other factors
Biodiversity is the assortment, or variety, of living things in an ecosystem.
Rain forests have more biodiversity than other locations in the world, but are threatened by human activities

18. Biotic and Abiotic Factors
A keystone species is a species that has an unusually large effect on its ecosystem.
They form and maintain a complex web of life
keystone

19. Biotic and Abiotic Factors
creation of
wetland
ecosystem
increased waterfowl
Population
increased fish
population
nesting sites for birds
keystone species

20. Habitat and Niche
Every organism has a habitat and a niche.

21. Habitat and Niche A habitat differs from a niche.
A habitat is all aspects of the area in which an organism lives
Biotic factors
Abiotic factors
Your address

22. Habitat and Niche
An ecological niche includes all of the factors that a species needs to survive, stay healthy, and reproduce
Food
Abiotic conditions
Behavior
Your occupation

23. Habitat and Niche
Species can share habitats but cannot occupy the same niche in the same ecosystem.
Competition occurs when two species use resources in the same way (occupy same niche)
Competitive exclusion keeps two species from occupying the same niche.

24. Competitive exclusion has three different outcomes:
Habitat and Niche
Competitive exclusion has three different outcomes:
One species is better suited to the niche and the other will either be pushed out or become extinct.
The niche will be divided.
The two species will further diverge.

25. Habitat and Niche
Ecological equivalents are species that occupy similar niches but live in different geographical regions.
Madagascar
South America

26. Community Interactions
Organisms interact as individuals and as populations

27. Community Interactions
There are three main ways in which organisms interact:
Competition
Predation
Symbiosis
Mutualism
Commensalism
Parasitism

28. Community Interactions
Resource availability gives structure to a community.
Competition occurs when two organisms fight for the same limited resource.
Types of competition:
Intraspecific
Interspecific

29. Community Interactions
Predation occurs when one organism captures and eats another organism.
Predator
Prey

30. Community Interactions
Symbiosis is a relationship in which two species live closely.
Three types:
Mutualism
Commensalism
Parasitism

31. Community Interactions
Mutualism: both organisms benefit

32. Community Interactions
Commensalism: one organisms benefits, the other is unharmed.
Demodicids
Eyelash mites find all they need to survive in the tiny follicles
of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope.
Human:
Our eyelashes are home to tiny mites
that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle.

33. Community Interactions
Parasitism: one organism benefits, the other is harmed.
Hornworm caterpillar
The host hornworm will eventually die as its organs are consumed
by wasp larvae.
Braconid wasp
Braconid larvae feed on their host and release themselves shortly before reaching
the pupae stage of development.

34. Community Interactions
Endoparasites
Hookworms
Extoparasites
Leeches
Endoparasites
Live in tissue and organs of organism
Feed on nutrients ingested by host
Examples: tapeworms, protozoan, hookworms
Extoparasites
Exterior of organism
Feed on host fluids
Example: leeches, fleas, ticks

35. Population Density And Distribution
Each population has a density, a dispersion, and a reproductive strategy.

36. Population Density And Distribution
Population density is the number of individuals that live in a defined area.
a measurement of the number of individuals living in a defined space.
Scientists can calculate population density.

37. Population Density And Distribution
Geographic dispersion of a population shows how individuals in a population are spaced.
Population dispersion refers to how a population is spread in an area.
There are three types of dispersion:
Clumped
Uniform
Random
Clumped
dispersion
Uniform
Random

38. Population Density And Distribution
Clumped

39. Population Density And Distribution
Uniform

40. Population Density And Distribution
Random

41. Population Density And Distribution
Survivorship curves help to describe the reproductive strategy of a species.
Diagram showing the number of surviving members over time from a measured set of births.

42. Population Density And Distribution
Survivorship curves can be type I, II or III
Type I -low level of infant mortality and an older population
Common to large mammals and humans
Type II -survivorship rate is equal at all stages of life
Common to birds and reptiles
Type III -very high birth rate, very high infant mortality.
Common to invertebrates and plants

43. Population Density And Distribution

44. Population and Growth Patterns
Populations grow in predictable patterns

45. Population and Growth Patterns
The size of a population is always changing.
Four factors affect the size of a population:
Immigration:
organisms coming into a ecosystem
Births
Emigration
Organisms leaving an ecosystem
Deaths

46. Population and Growth Patterns
Population growth is based on available resources.
There are two types of growth:
Exponential
Logistic

47. Population and Growth Patterns
Exponential growth is a rapid population increase due to an abundance of resources.

48. Population and Growth Patterns
Logistic growth is due to a population facing limited resources.
Population will level out around carrying capacity.

49. Population and Growth Patterns
Carrying capacity is the maximum number of individuals in a population that the environment can support.
A population crash is a dramatic decline in the size of a population over a short period of time.

50. Population and Growth Patterns
Ecological factors limit population growth.
A limiting factor is something that keeps the size of a population down.
There are two types of limiting factors:
Density dependent
Density Independent

51. Population and Growth Patterns
Density dependent limiting factors are affected by the number of individuals in a given area.
Examples:
Predation
Competition
Parasitism and disease

52. Population and Growth Patterns
Density independent limiting factors limit a population’s growth regardless of the density.
Examples:
Unusual weather
Natural disasters
human activities