1. Ecology
Pearland High School • 2008

2. What is Ecology
Ecology is the scientific study of interactions among organisms and between organisms and their environment.

3. Biotic & Abiotic Biotic – all living organisms (plants & animals).
Abiotic – all nonliving things (rocks, gases, minerals).
Biosphere – where all living and non living things are found (land, water, air).
Abiotic
Biotic

4. Biosphere Different populations make up the biosphere.
Population – groups of organisms of one species that live in the same place.
Populations use the same: food, water, mates, territory.
Different populations that interact make up Communities.
Examples: fish and alligators share the same territory (habitat) and interact with one another (predator/prey).
All the interactions make up the Ecosystem.
Biomass is the total amount of living tissue in a given area.

5. Levels of Organization
Biome

6. Levels of Organization
Biosphere
Biome
Ecosystem
Community
Population
Individual

7. Levels of Organization
Biosphere – part of Earth that contains life.
Biome – group of ecosystems that have similar climate and dominant communities.
Ecosystem – collection of all the organisms that live in a particular place along with all abiotic factors (nonliving).
Community – different populations that live together in the same area.
Population – groups of individuals that live in same area.
Individual – one member of a species living in the population.

8. Levels of Organization
Air, water, land
Rainforest, desert, tundra
Cactus, snakes, rocks, sand
Deer, rabbits, owls
Frogs in a lake
One frog

9. Niche
The status of an organism within its environment and community (affecting its survival as a species). What an organism does to stay alive. Ex. Bacteria decomposes dead organic material.

10. Autotrophs
Organisms that capture energy from sunlight or chemicals and use that energy to produce food are called autotrophs or producers.
They use light energy to convert carbon dioxide and water into oxygen and carbohydrates during a process called photosynthesis.
Several types of bacteria do this process.
Green Slime

11. Two Main Forms of Energy for Autotrophs
Sunlight
The main source of energy for life on earth: photosynthesis.
Chemical
Some organisms such as bacteria, rely on the energy stored in inorganic compounds: chemosynthesis.

12. Heterotrophs
Organisms that do not get energy directly from the physical environment, but from other organisms are called heterotrophs or consumers.
Heterotrophs are the consumers of the food chain.
They can't produce their own food using energy from the sun like an autotroph can.
Heterotrophs eat plants or other animals to get energy for life.

13. Types of Heterotrophs Herbivores - obtain energy by eating only plants
ex: cows, caterpillars, deer
Carnivores - obtain energy by eating animals
ex: snakes, dogs, owls
Omnivores - obtain energy by eating both plants and animals
ex: humans, bears, crows
Detritivore - obtain energy by feeding on plant and animal remains
ex: mites, earthworm, snails, crabs
Decomposers - breakdown organic matter
ex: bacteria, fungi

14. Energy Transfer
When an organism eats another organism, energy is transferred.
Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers).

15. How Does Energy Flow Through an Ecosystem?
Energy flows through an ecosystem in one direction,
Sun or chemicals
Autotrophs
Heterotrophs

16.     Trophic Levels Decomposers 5th  Quarternary 4th  Tertiary
Consume r s
5th  Quarternary
4th  Tertiary
3rd  Secondary
2nd  Primary
1st  Producers    

17. Trophic Levels 4th 3rd 2nd 1st Decomposers 4th  Secondary Carnivores
3rd  Primary Carnivores
2nd  Herbivores
1st  Producers
1st
2nd
3rd
4th
Decomposers

18. Energy Cycles
Energy flows through an ecosystem from producer to consumer and is eventually recycled by decomposers.
Each living thing is dependent on the other living things in the community.
Energy constantly cycles through the ecosystem.
Example: rabbit is born, rabbit lives a happy life, rabbit gets run over by car, vulture and coyotes eat remains and gain energy from food, bacteria decompose the rest of the living matter for energy.

19. Models of Energy Cycles
Food Chain – Most simple model which shows how energy flows from one organism to another. Only goes in one direction. Ex.: rabbit coyote bacteria
Food Web – network of interconnected food chains. Shows more than one path energy flows through environment.
Trophic Levels – each organism represents a step in which there is a 10% gain and the rest of the energy is lost to heat.
Ecological Pyramid – puts populations by numbers and energy level starting with producers at the bottom of the pyramid.

20. Food Chain
Energy is stored by producers can be passed through an ecosystem along a food chain.
A food chain is a series of steps which organisms transfer energy by eating and being eaten.
A food web links all the food chains in an ecosystem together.

21. Steps in a Food Chain
Each step in a food chain or web is called a trophic level.
Producers make up the first trophic level and consumers make up the higher levels.
An ecological pyramid shows the relative amounts of energy or matter contained within each trophic level in a food chain or web.

22. Food Chain

23. Food Web
A food web is used to represent the feeding relationships among the various organisms in an ecosystem that form a network of complex interactions.

24. Ecological Pyramids At each level energy is lost in the form of heat.
The greatest amount of available energy is found at the bottom level of the pyramid.
Producers are the living things that have the most energy available to them.

25. Types of Ecological Pyramids
Energy pyramid: only about 10% of the energy is transferred from on trophic level to the next, the rest is lost as heat.
Biomass pyramid: represents the amount of potential food available for each trophic level in an ecosystem.
Pyramid of numbers: shows the relative number of individual organisms at each trophic level.

26. Energy Pyramid
Energy flows through ecosystems from producers to the various levels of consumers.
Each time an organism eats another, not all the energy is transferred.

27. Energy of the Producers
Energy Pyramid
Only about 10% of the energy of a producer is transferred to the consumer that eats it.
Therefore, there is a progressive loss of energy at each level of a food chain.
We can represent the amount of energy at each level as a part of a pyramid.
Energy of the Producers
Primary Consumer
Other Consumers

28. Biomass Pyramid
It is possible to estimate the mass of all the organisms living in a given area or ecosystem.
This estimation is known as the biomass.
If the mass of the producers and each type of consumer is recorded, a pyramid can be constructed showing that the biomass of the producers is generally far greater than that of the consumers.
Biomass of Producers
Primary Consumers
Secondary Consumers
Tertiary Consumers

29. Pyramid of Numbers
A pyramid of numbers is a graphical representation of the numbers of individuals in each population in a food chain.
Often it is drawn from the autotrophic level up.
A pyramid of numbers can be used to examine how the population of a certain species affects another.
In a Lake Community 10
180
500
10000
In a Tree Community 3 20 76 1

30. Inter-Dependence Symbiosis – living together. Types of Symbiosis
One organism depending on another for its survival. This is a relationship all living things share.
Types of Symbiosis
Mutualism – both organisms benefit; ex. plants giving off O2 for animals and animals giving off CO2 for plants to use.
Parasitism – one organism benefits and the other is harmed; ex. tapeworm living in a person’s intestine.
Commensalism – one organism benefits and the other is not affected; ex. birds nesting in trees.

31. Environmental Homeostasis
Life is sustained by a balance of environmental factors and by maintaining a balance of nutrients that are necessary for living organisms.
These are water, carbon, and nitrogen.
Each of these cycles through the environment such that the balance can be maintained.

32. Water Cycle How the Environment Maintains Homeostasis

33. Carbon Cycle How the Environment Maintains Homeostasis

34. Nitrogen Cycle How the Environment Maintains Homeostasis

35. Population Dynamics Population growth is limited by certain factors:
Space available
Food
Competition for resources between different species
Number of mates
Natural disaster
Disease
Temperature
Each ecosystem has a carrying capacity.
This means the area can only support a certain number of each species due to the limiting factors for populations.

36. Human Populations Factors affecting Human Population growth:
Birth rate and Death rate
Birth rate – Death rate = population growth rate
Fertility
When fertility is high populations increase
Population Age
Very young / immature pre-reproductive
Reproductive mature ( only ones that can increase population )
Post-reproductive / very old
Mobility
Immigration – movement into a population
Emigration – movement out of a population

37. Ecological Homeostasis
Limiting factors are biotic and abiotic conditions that maintain balance in every community and keep populations from growing out of control.
Availability of food
Temperature
Shelter
Availability of mates
The ways communities grow into new niches is called Succession.
Primary Succession – colonization of new environments (ex. islands).
Secondary Succession – usually happens after natural disasters or other major changes to the environment.

38. Ecological Succession

39. The Major Biomes Tundra Taiga Temperate Deciduous Forest
Temperate Grassland
Desert
Savanna
Tropical Rain Forest
Freshwater and Saltwater Aquatic

40. Terrestrial Biomes
Biomes are very large terrestrial ecosystems that contain a number of smaller but related ecosystems within them.
A certain biome may exist in more than one location on Earth, but similar biomes have similar climates and tend to have inhabitants with similar adaptations.

41. Tundra
Biome: deciduous forest
A vast plain covered by low trees and shrubs growing in a thin layer of soil over permafrost.

42. A forest characterized by evergreen trees such as spruce and fir.
Taiga
Biome: deciduous forest
A forest characterized by evergreen trees such as spruce and fir.

43. Temperate Deciduous Forest
Biome: deciduous forest
A forest characterized by trees that shed their leaves in the fall.

44. Desert
Biome: grassland
An area that receives ten inches, or less, of precipitation per year.

45. Temperate Grasslands
Biome: grassland
Vast area covered with grasses of various heights depending on the amount of rainfall. The more the rainfall the tall the grasses.

46. Savanna
Biome: grassland
Subtropical or tropical grassland with tall grasses, scattered trees, and shrubs.

47. Tropical Rain Forest
Biome: grassland
Biome dominated by broad leafed evergreen trees, is near the equator, and has in excess of 300 inches of rain per year.

48. Just as populations contain interacting members of a single species, communities contain interacting populations of many species. Plants and animals as well as abiotic and biotic factors are all part of any ecosystem.
Carnivores…symbiotic relationships