This document discusses various topics related to environmental science and ecology including food chains, food webs, and forest ecosystems. It defines food chains as a series of steps where organisms transfer energy by eating and being eaten. Food webs show how different organisms are interconnected in an ecosystem. Ecological pyramids graphically represent trophic levels and show decreasing biomass at higher levels. Forest ecosystems support a variety of plant and animal life through processes like photosynthesis and decomposition. They help regulate climate and rainfall while providing habitat. The document provides details on different types of forests and their characteristic features.

1. ENVIRONMENTAL SCIENCE &
ENGINEERING

2. TOPICS
• FOOD CHAIN
• FOOD WEB
• ECOLOGICAL PRYMIDS
• FOREST ECO SYSTEM
• PREPARED BY,
VARUN
KARTHIKEYAN

3. FOOD CHAIN
Food Chain—series of steps in which organisms
transfer energy by eating and being eaten
Arrows go in the direction of how energy is
transferred
Start with producer and end with top consumer
or carnivore
Ex: grass cricket frog raccoon

4. TYPES OF FOOD CHAIN
• Grazing Food Chain
It Starts With Green Plants And Goes To The
Decomposer Food Chain
It Is Found In Grassland & Pond Ecosystem
Detritus Food Chain
It Starts With Dead Organic Matter
It Is Found In Grassland & Forest Ecosystem

5. IMPORTANT FACTS ABOUT FOOD
CHAINS
• In a food chain each organism obtains energy
from the one at the level below.
• Plants are called producers because they
create their own food through
photosynthesis3
• Animals are consumers because they cannot
create their own food, they must eat plants or
other animals to get the energy that they
need.

6. Trophic Levels—each step in a food chain
• 1. Level 1—Producers (autotrophs)
• 2. Level 2—Primary Consumers (herbivores)
• 3. Level 3—Secondary Consumers
(carnivores or omnivores)
• 4. Level 4—Tertiary Consumers
(carnivore—usually top carnivore)

7. FOOD WEB
• A food web is “an interlocking pattern of food
chains
• it show how plants and animals are connected
in many ways to help them all survive.
Hawks
Weasels Raccoons
Mice
Grass

8. FOOD WEB

9. ECOLOGICAL PYRAMIDS
• It’s A Graphical Representation Of The
Structure And Function Of Tropic Levels Of An
Ecosystem Is Called Ecological Pyramids
• Types Of Ecological Pyramids
• Pyramid By Numbers
• Pyramid Of Energy
• Pyramid Of Bio Mass

10. PYRAMID OF NUMBERS

11. PYRAMID OF ENERGY
Energy Pyramid shows relative amount of
energy available at each trophic level
• Organisms in a trophic level use the available
energy for life processes (such as growth,
photosynthesis, cellular respiration,
metabolism,etc.)and release some energy as
heat

12. PYRAMID BY ENERGY

13. PYRAMIDS OF BIOMASS
• IT represents the amount of living organic
matter at each trophic level
10%
100%
1%
0.1

14. Represents amount of energy
available at each level as well
as amount of living tissue—
both decrease with each
increasing trophic level
ENERGY AND BIOMASS PYRAMID
(TOGETHER)

15. FOREST ECOSYSTEM
• The forest is one of the main resource in
our world.
• Nearly it occupies 40% of the world’s
land area
• In india 19% of the land is occupied by
the forest

16. FORESTS
Deciduousforests Tropicalrainforests Coastalforests Coniferousforests
Aforestisanareainwhichthemainplantsthatgrowtherearetrees.

17. Deciduous Forest
• Large, flat leaves that
drop off in the Fall,
new leaves grow in
Spring.
• Leaves change color
with the seasons.
• These trees grow in
places that have warm,
wet summers and cold
winters. Winter

18. TROPICAL RAIN FOREST
• These trees grow in
places that are hot
and wet all year.
• Trees are very tall and
the leaves are always
green.
• The forest has three
layers.
Forest floor
Understory
Canopy

20. COASTAL FOREST
• Grows in places
where there is lots of
rain.
• Temperature is not
too hot or too cold,
just cool.
• Has three layers just
like the rain forest:
canopy, understory,
forest floor.

21. CONIFEROUS FOREST
• Grows in places with
very cold winters and
cool summers.
• The leaves look like
needles so they don’t
need very much water.
• Seeds grow in cones.
• Get less rain than all the
other forests.
Seed cone

22. CHARACTERISTICS OF FOREST
ECOSYSTEM
• It is characterised by the warm temperature
and adequate rainfall it make generation of no
of ponds ,lakes..
• It maintain climate and rainfall
• It gives shelter to wild animals
• Soil is rich in organic matter
• Lack of sunlight into forest so the conversation
of the organic matter into nutrients is very fast

23. ABIOTIC COMPONENTS OF FOREST
ECOSYSTEM
• It Is A Physical Components About The
Climate, Temperature, Light, Rainfall And
Minerals

24. THE BIOTIC COMPONENTS OF FOREST
ECOSYSTEMS
 Producers
(autotrophs)
- Photosynthesis
 Consumers
(heterotrophs)
- Aerobic
respiration
 Decomposers

27. THANK YOU
BY
– K.V.VARUN KARTHIKEYAN