PRINCIPLES OF ECOLOGY

1
CHAPTER 2

• PRINCIPLES OF ECOLOGY

2
ORGANISMS AND THEIR RELATIONSHIPS

• Main Idea for Ch. 2.1
• Biotic and abiotic factors interact in complex
  ways in communities and ecosystems.
• Discussion
• Who or what do you depend
  on?

3

• ECOLOGY
• Ecology is the scientific area in which the
  relationships among living organisms and the
  interactions the organisms have with their
  environments are studied.
• Scientists who study ecology are called
  ecologists.
• Ecologists perform tests in the environment where
  organisms live to find out why they die or live,
  grow in number or decrease, live in water or near
  the water, etc.
• Ecologists use models so they can test in a lab
  things that are happening in the environment.
• Models help scientists control the variables and
  study them one at a time.
• EX more or less water, more or less light,
  temperature changes, etc.
• Helps scientists completely understand the
  effects taking place in the environment.

4

• Discussion
• Which task would be completed by an ecologist?
• Survey and classify mollusk fossils
• Inoculate cattle against infection
• Test the effect of cyanide on algae
• Explore the medicinal uses of nectar
• What are some locations where you might find
  ecologists collecting data, and what tools might
  they use in these locations?
• What types of organisms have you ever observed or
  collected that live near your home?
• What are some interesting characteristics of
  these organisms?

5

• THE BIOSPHERE
• Biosphere is the portion of Earth that supports
  life.
• The prefix bio means life.
• Includes surface of earth, atmosphere, oceans,
  lakes, and extends down several kilometers below
  the surface to any location that includes life.
• EX
• Rainforest Desert
  Marine Life
• Ecologists study these organisms, their
  adaptations, and the factors in their
  environments.
• These factors are divided into 2 large groups.
• Living factors biotic
• Nonliving factor - abiotic

6

• BIOTIC FACTORS
• Anything living in an organisms environment are
  called biotic factors.
• The interactions among organisms are necessary
  for the health of all species in the same
  geographic location.
• What are some of the biotic factors in this
  picture and how do they relate to one another.

7

• ABIOTIC FACTORS
• Nonliving factors in an organisms environment
  are called abiotic factors.
• Abiotic factors include
• Temperature
• Air
• Water
• Sunlight
• Soil types
• Rainfall
• Nutrients
• Organisms depend on abiotic factors to survive.
• Organisms have adaptations to live with certain
  abiotic factors. If the abiotic factors change
  organisms need to change or they will die.
• Argument Oxygen is the only abiotic factor that
  allows you to survive in this classroom. So, as
  long as there is enough oxygen, all of you will
  survive.

8

• LEVELS OF ORGANIZATION
• Levels of organization increase in complexity as
  the numbers and interactions between organisms
  increase.
• Levels of organization are
• Organism
• Population
• Biological community
• Ecosystem
• Biome
• Biosphere

9

• ORGANISMS, POPULATIONS, AND BIOLOGICAL
  COMMUNITIES
• Organism is one individual
• Population is a single species that share the
  same geographic location at the same time.
• Individual organisms in the population
  compete for the same resources. If the
  resources are high, the population
  will grow. If not, the population will decrease.
  Eventually the population s will match the
  resources for the area.
• Biological community is a group of interacting
  populations that occupy the same geographic area
  at the same time.
• Different populations may or may not compete
  for resources.

10

• ECOSYSTEMS, BIOMES AND THE BIOSPHERE
• Ecosystem is a biological community
  including the abiotic factors that affect it.
• Ecosystems can be large or small
• Biome is a large group of ecosystems that share
  the same climate and have similar types of
  communities.
• Biosphere contains all of the biomes on Earth and
  is the highest level of organization.

11

• ECOSYSTEM INTERACTIONS
• Survival of the different populations increases
  if they use the resources in different ways.
• EX birds use different areas of the tree to
  build nests.
• Habitat is an area where an organism lives.
• EX deer covering 5 sq. miles to find food.
• Niche is the role or position that an organism
  has in its environment (habitat).
• EX food, shelter, and reproduction
• Discussion
• What is an example of a habitat and an
  individuals niche in that habitat?

12

• COMMUNITY INTERACTIONS
• Interactions in the community include competition
  for basic needs like food, shelter, mates, and
  how organisms depend on each other for survival.

13

• COMPETITION
• Competition occurs when more than 1 organism uses
  the resource at the same time.
• The organism that out competes the other one is
  the one that survives.
• PREDATION
• Predation is when one organism pursues and eats
  another organism for food.
• Predator is the organism that is
  doing the pursuing.
• Prey is the organism that is caught and ate.
• EX mallard duck eating water bug.

14

• SYMBIOTIC RELATIONSHIPS
• Symbiosis is the close relationship that exists
  when 2 or more species live together.
• There are 3 different types of symbiosis
• Mutualism
• Both organisms receive a benefit
• EX flowers and bees
• Commensalism
• One organism receives a benefit the other one
  is not hurt or harmed
• EX clownfish and sea anemones
• Parasitism
• One organism receives the benefit the other one
  is hurt or dies.
• EX Fleas, ticks, tapeworms, etc.

15

• Section 2.2
• FLOW OF ENERGY IN AN ECOSYSTEM
• Autotrophs capture energy, making it available
  for all members of a food web.
• The sun is the original source of energy!

16

• ENERGY IN AN ECOSYSTEM
• Organisms differ in how they obtain energy. They
  are either autotrophs or heterotrophs.
• AUTOTROPHS
• Autotrophs are organisms that collect energy from
  sunlight or inorganic substances to produce food.
• EX plants, bacteria
• Autotrophs are the foundation for all organisms
  in an ecosystem
• Autotrophs are also called producers
• Discussion What is the process by which
  autotrophs convert light energy into chemical
  energy?

17

• HETEROTROPHS
• Heterotroph is an organism that gets energy by
  consuming other organisms.
• Heterotrophs are also called consumers.
• Different types of consumers
• Herbivore only eats plants, EX rabbit, cow
• Carnivores only eat meat, EX wolves, lions
• Omnivores eat both meat plants, EX humans,
  bears
• Detritivores - eat fragments of dead matter in
  an ecosystem and return nutrients back to the
  soil, air, and water where the nutrient can be
  recycled by other organisms. EX worms
• Decomposers (similar to detritivores) break
  down dead organisms by releasing digestive
  enzymes. EX fungi (mushrooms), bacteria

18

• MODELS OF ENERGY FLOW
• Ecologists use food chains food webs to model
  the energy flow through an ecosystem.
• A trophic level is a step in a food chain or web.
• Autotrophs make up the first trophic level in all
  ecosystems.
• Heterotrophs make up the remaining levels.

19

• FOOD CHAINS
• Food chain is a simple model that show how energy
  flows through an ecosystem.
• In a food chain the energy ONLY
  flows in one direction, up the
  tropic levels.
• The arrows show what direction
  the energy flows, which usually
  starts with the autotrophs
  and moves to the
  heterotrophs.
• Some of the energy is not
  transferred from one trophic level
  to the next because it is used
  by the organism for new cells tissues.

20

• FOOD WEBS
• A food web is a model representing the many
  interconnected food chains and pathways in which
  energy flows through a group of organisms.

http//www.goldridge08.com/foodchain.htm
21

• ECOLOGICAL PYRAMIDS
• An ecological pyramid is a diagram that shows the
  relative amounts of energy biomass or numbers or
  organisms at each trophic level in an ecosystem.
• Energy pyramid only 10 of the energy is
  transferred to the next level.
• The organism uses 90 of the energy for
  bodily processes or released
  as heat.
• Biomass pyramid shows the amount of total mass of
  living matter at each trophic level
• Pyramid of numbers shows the number
  of organisms at each trophic level

22

• SECTION 2.3
• CYCLING OF MATTER
• Essential nutrients are cycled through
  biogeochemical processes.
• Discussion
• What would happen if matter was bound in living
  matter and never recycled?

23

• CYCLES IN THE BIOSPHERE
• Energy is transformed into usable forms to
  support life of an ecosystem.
• Constant supply needed so matter needs to be
  recycled.
• Matter is anything that takes up space and has
  mass.
• Nutrient is a chemical substance that an organism
  must obtain from its environment to sustain life
  and to undergo life processes.
• Biogeochemical cycle is the exchange of matter
  through the biosphere.
• Bio means life, geo means earth, chemical
• Producers (plants) use air, soil and water to
  convert them into usable nutrients. Consumers
  eat the plants the nutrients are passed to
  them. Decomposers will return the nutrients to
  be recycled.

24

• WATER CYCLE
• Water is constantly evaporating off of bodies of
  water go up into the atmosphere in the form of
  water vapor.
• 90 of all evaporation occurs over the ocean,
  lakes and rivers.
• 10 evaporates from plants through a process
  called transpiration.
• Water vapor creates clouds then precipitation.
• Ends up on the surface is soaked up by plants
  or remains underground. Can fall in lakes or
  streams return to ocean

25

• THE WATER CYCLE - CONTINUED
• Organisms cannot live without water.
• 3 of all water on Earth is fresh. 69 of all
  fresh water is either frozen in glaciers or
  underground.

26

• THE CARBON AND OXYGEN CYCLES
• All living things are composed of molecules that
  contain carbon, such as protein, carbohydrates
  and fats.
• Carbon and oxygen make up molecules essential for
  life, including carbon dioxide and simple sugars.
• In photosynthesis, plants and algae, will convert
  carbon dioxide water into carbohydrates
  oxygen for the atmosphere.
• These carbohydrates are used as a source of
  energy for all organisms in the food web.
• Carbon dioxide is recycled back into the
  atmosphere through cellular respiration. (You do
  cellular respiration)
• Carbon can be stored for long periods of time as
  fossil fuels released when burned, adding
  carbon dioxide to the atmosphere.

27

• Discussion
• Based on your understanding of the carbon cycle,
  predict what might happen if large areas of
  tropical rain forest continue to be cleared.
• How do you interact in the carbon cycle?

28

• THE NITROGEN CYCLE
• Nitrogen is an element.
• Largest amount found in atmosphere.
• Cant be used by plants and animals in this form
• Nitrogen fixation occurs when bacteria convert
  the nitrogen gas to nitrates.
• Enters food web when plants absorb nitrogen
  compounds from the soil convert them into
  protein.
• Nitrogen is often a limiting nutrient for the
  growth of producers.
• Decomposers will return nitrogen in protein back
  into ammonia.
• Denitrification occurs when bacteria convert the
  nitrogen compounds back into nitrogen gas
  returning it to the atmosphere.

29

• NITROGREN CYCLE

30

• THE PHOSPHORUS CYCLE
• Phosphorus essential for growth development of
  organisms.
• Short term cycle
• Soil ?producers ?consumers
• Decomposers return phosphorus to soil
• Long term cycle
• Stored in sedimentary rocks
• Released through weathering
  or erosion
• Phosphorus is a limiting nutrient.