Ecology

1
Ecology
2
What is Ecology?

• Ecology is the study of interactions among
  organisms and between organisms and their
  environment.
• Biosphere contains the combined portions of the
  planet in which life exists, including land,
  water, and air or atmosphere.

3
Levels of Organization

• Species is a group of organisms so similar to one
  another that they can breed and produce fertile
  offspring.
• Population are groups of individuals that belong
  to the same species and live in the same area.
• Communities are assemblages of the different
  populations that live together in a defined area.
• Ecosystem is a collection of all the organisms
  that live together in a particular place as well
  as their nonliving or physical environment.
• Biome is a group of ecosystems that have the same
  climate and similar dominant communities.

4
Animals get their food
5
Plants make their food by photosynthesis
5
Energy Flow

• Sunlight is the main source of energy for life
  on Earth.
• Organisms are divided into two groups based on
  how they obtain their Energy
• 1. Autotrophs Make their own food by converting
  energy and chemicals into food
• 2. Heterotrophs Must eat other organisms for
  their food.

6
Energy FlowAutotrophs

• The best know autotrophs are those that harness
  the power of the sun through photosynthesis.
  They use this energy to convert carbon dioxide
  and water into oxygen and glucose.
• The second type of autotrophs use chemical energy
  to make carbohydrates. This is performed by
  several types of bacteria.

7
Energy FlowTypes of Heterotrophs

• Herbivores obtain energy by eating plants.
• Carnivores eat animals.
• Omnivores eat both plants and animals.
• Detritivores feed on the remains of plants,
  animals and other dead matter.
• Decomposers breaks down organic matter.

8
Feeding Relationships

• Energy flows through an ecosystem in one
  direction, from the sun or inorganic compounds to
  autotrophs (producers) and then to various
  heterotrophs (consumers).
• Food Chains are a series of steps in which
  organisms transfer energy by eating or being
  eaten.
• Food webs show the complex interactions within an
  ecosystem.
• Each step in a food chain or web is called a
  trophic level. Producers make up the first step,
  consumers make up the higher levels.

9
Food Chain
A Food Chain is a series of steps in a community
of organisms that is used to transfer ENERGY and
MATTER by eating or being eaten.
The Steps are Called TROPHIC LEVELS
10
Food Web
A Food Web is a series of interconnected food
chains
Can You Still Identify the Trophic Levels here?
11
Food Web
12
Ecological Pyramids

• An ecological pyramid is a diagram that shows the
  relarive amounts of energy or matter contained
  within each trophic level in a food web or food
  chain.
• Energy Pyramid only 10 of the energy available
  within one trophic level is transferred to
  organisms at the next trophic level.

13
Roughly 10 of the energy is transferred
14
Pyramids Continued

• Biomass pyramids show the total amount of living
  food available at each trophic level.
• Numbers pyramid shows the number of species at
  each trophic level.
• Because each trophic level harvests only about
  one tenth of the energy from the level below, it
  can support only about one 10th the amount of
  living tissue.

15
BIOMASSPyramid
16
2
How do plants get their food ?
The soil was watered but nothing else was added.
After 5 years, the tree had gained 74kg in
weight but the soil had lost only 57g. van
Helmont concluded that the tree had made 74kg of
new growth from water alone
17
3

• van Helmonts experiment was effective in showing
  that the plants food did not come from the soil.
• But he had overlooked the fact that air was
  available to the plant as well as water.
• Could it be that the plant made 174kg of material
  from just air and water?
• This might seem unlikely but we now know that
  plants do indeed make their food from carbon
  dioxide from the air and water from the soil.

18
9
19
Photosynthesis
6
Green plants take in carbon dioxide (CO2) from
the air
They take up water (H2O) from the soil
The plants combine the CO2 with the H2O to make
the sugar, glucose (C6H12O6)
6CO2 6H2O C6H12O6 6O2
Oxygen (O2) is a by-product of this reaction
20
Photosynthesis
21
Photosynthesis
22
Energy
9

• It takes energy to make CO2 combine with H2O
• This energy comes from sunlight
• The energy is absorbed and used by a substance
  called chlorophyll

23
Leaf Anatomy
24
Chlorophyll
10

• Chlorophyll is a green coloured chemical
• It is present in the leaves of green plants
• The chlorophyll in the cells is packaged into
  tiny structures called chloroplasts
• The next slide shows a diagram of leaf cells with
  their chloroplasts

25
Plant Cell
26
(No Transcript)
27
Anatomy of a Leaf
28
(No Transcript)
29
What happens to the glucose?
15

• The glucose made by the chloroplast is either
• (a) used to provide energy for the chemical
  processes in the cell ( by respiration)
• (b)turned into sucrose and transported to
  other parts of the plant
• or
• (c) turned into starch and stored in the cell
  as starch grains
• In darkness the starch is changed back into
  glucose and transported out of the cell

30
23
TO SUM UP

• Plants combine carbon dioxide from the air,
  and water from the soil to make glucose.
• The energy needed for this process comes from
  sunlight
• The sunlight is absorbed by chlorophyll
  contained in the chloroplasts of the leaf.
• The glucose can be used for energy or to make
  other substances.
• To make other substances, the glucose must be
  combined with other chemical elements such as
  nitrogen and potassium.
• These chemical elements are present in the
  soil and are taken up in solution by the roots.

31
Respiration use of oxygen to burn food for
energy
32
Respiration Chemical Formula
Its the Reverse of Photosynthesis
33
Feeding
4

• Animals get their food by eating plants, or other
  animals
• Carnivores eat animals
• Herbivores eat plants
• Plants make their own food
• They combine carbon dioxide from the air with
  water and dissolved salts from the soil
• Plants do NOT get their food from the soil
• The process by which plants make food is called
  PHOTOSYNTHESIS

34
Question 1
25

• For a plant to make glucose it needs
• (a) CO2 and H2O
• (b) CO2, H2O and sunlight
• (c) CO2, H2O, sunlight and chlorophyll
• (d) CO2, H2O, sunlight, chlorophyll
• and nitrates

35
Question 2
26

• A by-product of photosynthesis is
• (a) Water vapour
• (b) Oxygen
• (c) Carbon dioxide
• (d) Nitrogen

36
Question 3
29

• The food made by photosynthesis is stored as the
  plant in the form of
• (a) Glucose
• (b) Sucrose
• (c) Starch
• (e) Cytoplasm

37
Cycles of Matter

• Unlike the one-way flow of energy, matter is
  recycled within and between ecosystems.
• These cycles are the water cycle, Nutrient Cycle,
  Carbon Cycle, nitrogen cycle and phosphorus
  cycle.
• These cycles are important so that the matter can
  be re-used by living things.

38
Carbon Cycle
39
Oxygen/Carbon Cycle
40
Nitrogen Cycle
41
The Nitrogen Cycle
Nitrogen gas (N2)
Plants Make Proteins with Nitrates
Animals Make Proteins by consuming Plant or other
organisms
Waste
Soil Bacteria
Soil Bacteria
Nitrite (NO2)
Nitrate NO3
Nitrate (NO3)
42
Nitrogen Cycle
FOOD contains PROTEIN
Nitrogen is in the fish in the form of PROTEIN__
NO3 is absorbed by the plant roots and made
into __________________________ that can be
used in food
Nitrogen in the waste is in the form of
AMMONIA NH3
WASTE (NH3) (NH4)
Uneaten food is decomposed into Ammonia (NH3)
by BACTERIA
NO3 is eaten decomposed by a bac3erial
called __NITROBACTER__ into ____NITRATE, NO3 ___
Ammonia is eaten decomposed by a bacteria
called _NITROSOMONAS into NITRITE, NO2
(NO2) Nitrite
43
Nitrates
19

• Nitrates are present in the soil, dissolved in
  water
• The plants take up nitrates in the soil water
• The nitrates are conducted through the roots to
  the stem and then to the leaves
• In the leaves, the nitrates and glucose are
  combined to make proteins
• This process is called assimilation

44
(No Transcript)