1. Ecology

2. Study of relationships between organisms and their environments.
WHAT IS ECOLOGY?
Study of relationships between organisms and their environments.
Biotic factors: all living parts of the environm.
Abiotic factors: nonliving parts of the environm.
(i.e. temperature, soil, light, moisture)
What do you think about when I say ecology? Recycling? Acid rain?

3. Biosphere Biome Ecosystem Community Population Organism
Levels of Ecological
Organization
largest
smallest
Just like with classification, ecology is hierarchal. Each level builds on itself and they fit together like nesting boxes.

4. 1. Biosphere: Earth (all ecosystems)
2. Biome: ecosystems with similar life and climate ex.: tropical rainforests, tundra
3. Ecosystem: Smallest group containing both biotic and abiotic factors
4. Community: Group of different populations in an area (No abiotic factors)
5. Population: a group of organisms of same species
6. Organism: an individual.
Lets review. Organisms make up populations, populations make up communities, communities and abiotic factors make up ecosystems, and all of the ecosystems make up the biosphere. From one to many and each depending on the other.

5. Habitat vs. Niche Niche - the role a species plays in a community
Habitat- the place where an organism lives
Limiting factor- biotic or abiotic factors that limits where an organism can survive
Ex.: amount of water available, food, space, shelter
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

6. Community Relationships
1. Competition for resources: food, shelter, water, etc. 2. Predation predator kill prey for food 3. Symbiosis different species living closely together
How do they trap the sun’s energy? Through what process? What is that process similar to in animal cells?

7. - + Types of Symbiosis: 1. Commensalism 2. Parasitism 3. Mutualism
Type of relationship
Species harmed
Species benefits
Species neutral
Commensalism +
Parasitism -
Mutualism
Cleaning shrimp

8. Commensalism- one species benefits, the other is neither harmed nor helped Ex. orchids on a tree
Epiphytes: A plant, such as a tropical orchid or a bromeliad, that grows on another plant upon which it depends for mechanical support but not for nutrients. Also called xerophyte, air plant.

9. one species benefits (parasite) and the other is harmed (host)
Parasitism-
one species benefits (parasite) and the other is harmed (host)
Ex.: fleas, mosquitos, etc..
Note: parasites want to keep host alive! (why?)

10. Mutualism- both species benefit each other Ex
Mutualism- both species benefit each other Ex. cleaning birds and alligators, lichen
The Egyptian plover takes insects from the backs of buffaloes, giraffes and rhinos. The plover has also been observed taking leeches from the open mouths of crocodiles! In this association the plover receives a supply of food and the other animal rids itself of unwelcome pests

11. The food web: trophic levels
Producer = autotrophs - Make own food -
Consumer = heterotrophs - Consume food
-Can be:
primary -> herbivores (eat plants)
secondary,tertiary -> carnivores (eat meat) or omnivores (eat meat and plants)
Always bottom of food chain
Trophic Level: Each link in a food chain;
A feeding step in transfer of energy in ecosystem.
How do they trap the sun’s energy? Through what process? What is that process similar to in animal cells?

12. Other feeding categories: Scavengers: eat decaying animals
Ex: vultures
Detritivores: eat pieces of organic matter in soil
Ex: worms, crabs
decomposers: absorb (do not “eat”) nutrients from decaying organic matter
Ex: fungi
Scavengers are a type of carnivore that eat dead animals, or carrion. Vultures, hyenas, crabs, deep sea fish-talk about distance from the sun and must eat the dead things that sink to the bottom, bottom feeders

13. Trophic Levels flow of energy
0.1% Tertiary consumers- top carnivores, omnivores
1% Secondary consumers-small carnivores
10% Primary consumers- Herbivores
100% Producers- Autotrophs

14. Only 10% of energy and biomass are transferred from bottom of food pyramid to the top!
*Biomass= amount of organic matter in a group of organisms in a habitat.
As you move up a food chain, both available energy and biomass decrease.
Energy is transferred upwards but is diminished with each transfer.

17. Trophic Levels
Food chain- linear model of energy flow **Arrow points from food to eater!

18. Food web- network of food chains

19. Food chain Food web
Linear group of food chains

22. -Cycles of Matter through biotic and abiotic factors:
Nutrient Cycles
-Cycles of Matter through biotic and abiotic factors:
1. Water cycle
2. Carbon cycle
3. Nitrogen cycle

23. Water cycle- Evaporation,transpiration, condensation,precipitation

24. Carbon cycle- Photosynthesis and respiration, combustion and decomposition cycle carbon and oxygen in environment.

25. Nitrogen cycle-
Atmospheric nitrogen (N2) makes up nearly 78%-80% of air.
Organisms can not use it in that form.
Lightning and bacteria convert nitrogen into usable forms.

26. Nitrogen cycle-
Only in certain bacteria and industrial technologies can fix nitrogen.
Nitrogen fixation-convert atmospheric nitrogen (N2) into ammonium (NH4+) which can be used to make organic compounds like amino acids.
N2 NH4+

27. Nitrogen-fixing bacteria: live in symbiotic relationship with plants of the legume family (e.g., soybeans, clover, peanuts).

28. Nitrogen cycle-
Some nitrogen-fixing bacteria live free in the soil.
Nitrogen-fixing cyanobacteria are essential to maintaining the fertility of semi-aquatic environments like rice paddies.

30. Nitrogen Cycle Atmospheric nitrogen Lightning
Denitrification by bacteria
Animals
Nitrogen fixing bacteria
Plants
Decomposers
Nitrification by bacteria
Nitrites
Nitrates
Ammonium

31. Pollution in food chains-
While energy decreases as it moves up the food chain, toxins increase in potency!!
This is called biological magnification
Ex: DDT & Bald Eagles

32. Succession Succession - a series of predictable changes that occurs
in a community over time
Two types:
1. primary succession
2. secondary succession
Terms:
pioneer species – the first organisms that live in a previously
uninhabited area
climax community – a stable, mature community that undergoes
little or no change
limiting factors – environmental factors that affect an organism’s
ability to survive (food, predators, space)
Each biome on Earth has a different type of climax community
- grasslands - rainforest

33. Primary Succession Secondary Succession occurs when a disturbance
of some kind changes an
existing community without
removing the soil
occurs on surfaces where
no soil exists
the colonization of new sites
by communities of organisms
called pioneer species
takes less time than primary
succession because soil is
already present
disturbances include wildfires,
storms, deforestation, farming
rocks
 lichens
 mosses 
 grasses, shrubs
 trees
soil
 grasses, shrubs
 trees

34. Population growth = an increase in the size of a population over time
 birthrate greater than death rate  population grows
 birthrate equals death rate  population stays the same
 death rate greater than birthrate  population shrinks
Under ideal conditions with unlimited resources, a
population will grow exponentially
exponential growth = as a population
gets larger, it also grows faster
Increase
Population decrease population

35. Two types of Limiting Factors:
Limiting factor = Any biotic or abiotic factor that restricts the numbers of organisms
Examples: food, water, shelter, etc
Two types of Limiting Factors:
density-dependent
density-independent

36. Density-dependent limiting factors
- CAUSED BY BIOTIC FACTORS.
Ex.: number of individuals in a given area
competition and availability of food, water and space
predation
parasitism and disease
DEPENDS on the # of individuals

37. Density-independent limiting factors
-Caused by abiotic factors
Ex.: limit a population’s growth regardless of the density
of the population
unusual weather
natural disasters
human activities (pollution or dam building)

38. CARRYING CAPACITY
The maximum number of individuals that can be supported by the ecosystem.
The limit is determined by the availability of resources and by their interactions with other organisms.

39. LOGISTIC GROWTH CURVE “S” CURVE
Occurs when population growth is limited by factors in the environment
Reaches carrying capacity
“S” curve
carrying
capacity
As resources become less
available, the growth of the
population slows or stops.
All organism eventually reach this

40. EXPONENTIAL GROWTH CURVE “J” CURVE
Population growth is NOT limited
Takes on an J-shape
Ideal and doesn’t normally occur in most populations
What kinds of organisms might have exponential growth and why?
R-Strategist

41. REPRODUCTIVE PATTERNS
Species of organisms vary in the number of births per reproductive cycle, in the age that reproduction begins, and in the life span of the organism.
R-strategist
K-strategist

42. R-strategist Small organism (fruit fly or a mouse) Short life span
Produce many offspring
Strategy is to produce as many offspring as possible in a short time in order to take advantage of some environmental factors
Populations are controlled by density- independent factors (changes in abiotic factors)

43. K-strategist (also called Carrying Capacity Strategy)
Large organism (elephant)
Long life span
Produce fewer offspring but invest a lot of care
Strategy is to produce only a few offspring who have a better chance of living due the care they get from parents
Populations are controlled by density-dependent (biotic factors)

44. Which are you?
R-strategist
K-strategist

45. Human Impact on the Environment
1. Effects of Human Overpopulation:
loss of land/habitat
water and food shortage
poor sanitation
species extinction
poverty
emerging disease
2. deforestation
- cause soil erosion, loss of habitat, and species extinction
3. threaten biodiversity
4. pesticide use – using chemicals to kill and control pests
- will sometimes kill non-target species
- pollutes water sources
- causes health problems
5. bioaccumulation/biological magnification
– concentrations of a harmful substance increase
in organisms at higher trophic levels in a food web

46. Human Impact on the Environment
Global Warming
Acid Rain
Pollution from fossil fuels
makes rain acidic
pollution in our atmosphere
causes too much heat to
stay on earth
changes overall temperature/
climate
raises sea level
affects health of ecosystems
causes health problems
damages forests and lakes
damages buildings

47. Effects on Water Quality
The runoff of silt, soil, pesticides, and fertilizers from agricultural
land is the largest single source of water pollution.
Eutrophication:
- excess fertilizers can run off into lakes and ponds
- this stimulates plant and algae overgrowth
- a buildup of algae can lower the levels of dissolved oxygen in
the water
- this leads to the dying off of the fish population
- over time, lakes and ponds slowly begin to fill in
Why can’t you just clean up
polluted water?
- it is expensive
- who pays for it?
- technology not available for all types

48. Effects on Natural Resources
Renewable resources
- can regenerate if they are living or can be replenished
by biochemical cycles if they are nonliving
- ex. trees, fresh water
Nonrenewable resources
- cannot be replenished by natural processes
- ex. fossil fuels
Sustainability = a way of using natural resources without
depleting them for future generations
use renewable resources that can be “restocked”
recycle and reuse products
plant tree farms
only cut down selected trees instead of clear-cutting
follow emission standards 48

49. The Story of Easter Island
Humans first landed on Easter Island between 400 and 700 A.D.
Island had thick forests, rich soil, many bird and animal species
Human population grew quickly over next 1000 years
They cut down forests for lumber and boats faster than the trees
could grow back
Eventually, there were no trees left….no wood for shelter or boats,
rich soil washed away, habitat lost for animal species, no fishing
without boats
With no food, and island resources nearly gone, the Easter Island
human population crashed and the Easter Islanders disappeared.