1. Ecology
Branch of biology that studies the interactions between organisms and their environment

2. All of the locations on Earth that can support life
Biosphere

3. Abiotic Vs. Biotic Non living factor in an environment Examples rocks
water
sunlight

4. Abiotic Vs. Biotic Living factors in an environment Examples plants
animals
bacteria

5. Levels of life Ecologists look at individual organisms (level 1)
organisms that have similar characteristics can mate and produce fertile offspring are a species

6. Population
Group of organisms of a single species that live in a given area

7. Community
A collection of interacting populations in a given area

8. Ecosystem
Collection of organisms that interact with each other and with abiotic factors in the environment

9. Landscape
a group of ecosystems which affect one another

10. Ecotone (edge effect)
a transition area between ecosystems, with blended characteristics

12. Ecotones are often caused by underlying environmental gradients

14. Energy in the Ecosystem

15. Organisms Autotrophs-make own food producers
Heterotroph-must get nutrients from outside sources consumers

16. Organisms
Carnivore
Herbivore
Omnivore

17. Organisms Decomposers: break down dead organisms into simple molecules
Scavengers: feed off dead animals

18. Trophic Level
Feeding level on food, energy, or biomass pyramid
Starts with primary producers
Ends with highest level consumer

19. Food Chain One set of organisms moving up through the trophic levels
Grass mouse fox hawk

20. Food Web
Interconnecting food chains in an ecological community
More than one food chain

25. Illustrates that energy decreases at each succeeding trophic level
Energy Pyramid
Illustrates that energy decreases at each succeeding trophic level
Usually square shaped
Only 10% energy moves up

28. Populations

29. populations
Group of organisms of the same species living in the same location
Change in population size is called growth rate (can be + or -)

30. Populations Can Grow, Shrink, or Remain Stable
Population size governed by
Births
Deaths
Immigration
Emigration
Population change =
(births + immigration) – (deaths + emigration)

31. Growing population Ideal conditions Healthy organisms reproduce faster
Birth rate is higher than death rate

32. Species Have Different Reproductive Patterns
r-Selected species
Short life
Rapid growth
Early maturity
Many small offspring
Low on trophic level

33. Characteristics of r-selected reproductive pattern species
Unpredictable environments
Small body size
Mature rapidly
Reproduce early
Short life span

35. Species Have Different Reproductive Patterns
K-selected species
Long life
Slow growth
Late maturity
Few, larger offspring
High on trophic level

36. Characteristics of K-selected reproductive species
Reproduce and mature slowly
Long-lived
Large body size

38. Carrying capacity (k)
Largest number of individuals that can survive over long periods of time in a given environment
Size of population is stabilized

39. Many species grow until capacity is reached and then level off BUT….

40. Boom and Bust
Some species -
exponential growth and then fast crash
can rise again or wait for some time before another boom

41. Exponential Growth, Overshoot, and Population Crash of a Reindeer

43. Density Dependent Limiting Factors
Operate more strongly on large populations
Usually works on stable populations

44. Density Dependant Factors
Disease
Parasites
Competition (food, space)
Stress

45. Density Independent Limiting Factors
Weather – storms, fires, droughts, heat, cold, floods, hurricanes
Human activities – toxic waste spill, pesticides, clear cutting

46. Coevolution
the evolution of complementary adaptations in two or more species of organisms because of a special relationship that exists between them

47. Examples Predator/ prey relationship
Cheetah can run very fast but lacks stamina
Gazelles have evolved stamina to escape cheetahs

48. Batesian Mimicry
A harmless species (non poisonous) resembles a poisonous species

49. Which butterfly has a bitter taste?

50. Mullerian Mimicry
Two poisonous species look alike

51. Queen Butterfly and Monarch are both poisonous

52. Population Interactions Influence Abundance
When populations of different species interact, the effects on one on the other may be positive (+), negative (-) or neutral (0).
By comparing populations living alone and together, several types of interactions can be identified.

53. FIVE IMPORTANT INTERACTIONS BETWEEN TWO SPECIES
COMMENSALISM (+/0)
MUTUALISM (+/+)
COMPETITION (-/-)
PARASITISM (+/-)
PREDATION (+/-)
The symbols +, - and 0 refer to the effect of one species on another when both are living together.

54. Competition LIVING ALONE LIVING TOGETHER COMPETITION 0 0 - -
[When both populations live together, abundance of each is lower.]

55. Law of Competitive Exclusion
No two species will occupy the same niche and compete for exactly the same resources for an extended period of time.
One will either migrate, become extinct, or partition the resource and utilize a sub-set of the same resource.
Given resource can only be partitioned a finite number of times.

56. Resource Partitioning

57. Competition
Interspecific - Competition between members of different species.
Intraspecific - Competition among members of the same species.
Often intense due to same space and nutritional requirements.
Territoriality - Organisms defend specific area containing resources, primarily against members of own species.
Resource Allocation and Spacing

58. Intraspecific Competition
Resource depletion may result in too many individuals in the population. Thus, the population crashes.
Reindeer on Saint Matthews Island died off as the result of depletion of lichens (food).

59. Intraspecific Competition
A seed company tells gardeners that planting plants too far apart or too close together will only produce a few seeds. Why?

60. Intraspecific Competition
Territorial behavior has evolved in many species as a response to intraspecific competition.
Male red wing blackbirds stake out a territory in defense of nests and mates.

61. Interspecific Competition

62. Predation LIVING ALONE LIVING TOGETHER PREDATION + - - +
[Prey (A) are in greatest abundance when predators are absent. Predators (B) are in greatest abundance when prey are present.]

63. Predation Feeds directly upon another living organism
Prey most successfully on slowest, weakest, least fit members of target population.
Reduce competition, population overgrowth, and stimulate natural selection.

64. symbiosis Intimate living together of members of two or more species.
Commensalism - One member benefits while other is neither benefited nor harmed.
Cattle and Cattle Egrets
Mutualism - Both members benefit.
Bees and flowers
Parasitism - One member benefits at the expense of other.
Humans and Tapeworms

65. COMMENSALISM COMMENALISM 0 0 + 0
LIVING ALONE LIVING TOGETHER
A B A B
COMMENALISM
Species A is more abundant when there are more of species B present. Species B is not affected by the presence of A

66. COMMENSALISM
The cattle egret and cattle or other grazing African ungulate species.
The egret benefits from catching insects that cattle “scare-up” while grazing.
Cattle unaffected.

67. COMMENSALISM
Bromeliads are a group of flowering plants that attach to trees (epiphytes). They gain access to sunlight and catch water.
The trees are not harmed or benefited.

68. Mutualism LIVING ALONE LIVING TOGETHER MUTUALISM - - + +
A B A B
MUTUALISM
[Both populations are found in greatest abundance when together.]

69. MUTUALISM
pollination of flowering plants by an insect or humming bird.
The pollinator benefits from the interaction by receiving nectar.
The plant gets its pollen transferred from one plant to another.

70. MUTUALISM
The lichen is a mutualistic association between a species of algae and a species of fungus.
The fungus retains water and takes up minerals.
The algae provides carbohydrates and other organic nutrients as the result of photosynthesis.

71. Parasitism
LIVING ALONE LIVING TOGETHER
A B A B
Parasitism

72. Parasitism
Tick feeds off mammal benefitting the tick but harming the mammal.

73. How would this ecosystem be affected if the butterfly population decreased?
How would this ecosystem be affected if the coyote population decreased
How would this ecosystem be affected if the raven population increased?

74. Limitations of where a species can live
Physiological stress due to environmental conditions
Competition with other species
Predation
Parasitism and disease
luck

75. Critical Environmental Factors
Single factor in shortest supply relative to demand is the critical determinant in species distribution.
Example: a cactus species can not survive if temperature drops below 30º F for more than 12 hours.

76. Tolerance Limits
Each environmental factor has both minimum and maximum levels, tolerance limits, beyond which a particular species cannot survive
Combination of many factors: temperature range, food availability, competitors, predators

77. Tolerance Limits

78. Limits of Range Physical Barriers Oceans (humans, cattle, marsupials)
Mountains (house finch)
Ice (cactus, coral reefs)
Climatic
Altitude
Food
Water
Competitors

79. Indicators
If we know the tolerance range of species, we can deduce the conditions in the environment based on the presence of a particular species
Example: trout require cool, clean well oxygenated water; if you see an abundance of trout, what does that tell you about the environment?

80. Ecological Niche
Habitat - Place or set of environmental conditions where a particular organism lives.
Ecological Niche
Role a species plays in a biological community (e.g. large grassland herbivore)
Total set of environmental factors that determines a species’ distribution.
Generalists - Broad niche
Specialists - Narrow niche
When generalists and specialists collide, generalists usually win.

81. Generalists North and Central America
Omnivorous: berries, insects, eggs, small animals

82. Specialists
China
Eat Bamboo

83. Keystone Species
A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass
Large predators
Critical food organisms (bamboo and pandas)
Often, many species are intricately interconnected so that it is difficult to tell which is the essential component.

84. Starfish: Keystone Species
Feeds on muscles and sea urchins
Muscles will outcompete other species
Sea Urchins over populate: decrease in corals