+ Food Chains and Food Webs Ms. McCray 6 th Grade Science April
24 & 25
Slide 2
+ Standards We Will Address 6.L.2.1 Summarize how energy
derived from the sun is used by plants to produce sugars
(photosynthesis) and is transferred within a food chain or food web
(terrestrial and aquatic) from producers to consumers to
decomposers. 6.L.2.2 Explain how plants respond to external stimuli
(including dormancy and forms of tropism) to enhance survival in an
environment. 6.L.2.3 Summarize how the abiotic factors (such as
temperature, water, sunlight, and soil quality) of biomes
(freshwater, marine, forest, grasslands, desert, Tundra) affect the
ability of organisms to grow, survive and/or create their own food
through photosynthesis.
Slide 3
+ Transfer of Energy Energy is derived (taken) from the sun and
used by plants to produce sugars (photosynthesis) and is
transferred within a food chain or food web from producers to
consumers to decomposers.
Slide 4
+ Difference Between Food Chains and Food Webs Food webs: show
how plants and animals are interconnected by different paths.
Example: Trees produce acorns which provide food for mice and
insects. Food chains: follows a single path as animals eat each
other (or eat plants) Example: Cow eats grass Example: Shark eats
seal
Slide 5
+ Types of Food Webs/Chains There are two places we find food
webs/chains: on land and in water. On land they are called
terrestrial In water they are called aquatic
Slide 6
+ What Are Producers? A producer is something that PRODUCES its
own food! Plants food is glucose which is a type of sugar. They
make this sugar using sun light, water, and carbon dioxide. This
process is called photosynthesis.
Slide 7
+ What Are Consumers? Consumers must eat other things (plants
or animals) to survive. There are three types of consumers:
Herbivores: animals that eat only plants Example: cows, rabbits
Carnivores: animals that eat only meat Example: T-rex, Omnivores:
animals that eat both plants and animals
Slide 8
+ What Are Decomposers?
Slide 9
+ Bacteria and fungi are two types of decomposers. Decomposers
return nutrients to the soil and air. They extract carbon from
their food and it mixes with oxygen to create carbon dioxide.
Examples are rotting logs, animals decaying, and mold on
bread.
Slide 10
+ Bacteria in the Gut Gut flora or bacteria live in the
digestive tract of most animals. These bacteria provide many useful
functions for the host (the animal they live in) such as:
Preventing growth of harmful bacteria Producing vitamins for the
host Producing hormones that direct the host to store fat.
Slide 11
+ Bacteria in Plant Roots Bacteria live on plant roots and they
convert nitrogen in the air into organic compounds (a chemical that
contains carbon) that the plant can use. The plant then uses these
organic compounds to make proteins that the animals will eat and
use for energy.
Slide 12
+ Fun (and Important) Facts! In case you havent noticed, carbon
is very important to plants and animals. Without carbon, life would
not exist. Bacteria make up about 60% of the dry mass of feces
(poop)!!
Slide 13
+ Levels of Organization Species- a group of organisms that are
physically similar and can mate with each other and produce
offspring that can also mate and reproduce Population- all member
of one species in a particular area Community- all different
populations that live together in an area
Slide 14
+ Predation An interaction in which on organism kills another
for food Predator- the organism that does the killing Prey- the
organism that is killed
Slide 15
+ Standard 6.L.2.2 Changes in Environmental Conditions Changes
in environmental conditions can affect the survival of individual
organisms and entire species.
Slide 16
+ Dormancy Dormancy is a period of inactivity in a mature seed
prior to germination; seed remains dormant until conditions are
favorable for growth and development of the new plant
Slide 17
+ Plants Adapt Plants grow, reproduce, and shift the position
of their roots, stems and leaves in response to environmental
conditions such as gravity, sunlight, temperature and day
length.
Slide 18
+ Tropism Tropism is a plants turning or bending movement of an
organism toward or away from an external stimulus such as light,
heat or gravity. If the tropism is positive, the plant grows toward
the stimulus. If the tropism is negative, the plant grows away from
the stimulus
Slide 19
+ Biotic and Abiotic Factors Water, nitrogen, carbon dioxide,
and oxygen are substances cycled between the living and non-living
environments. Abiotic factors are any non-living things in an
environment. Examples: air, water, sunlight Biotic factors are any
living things in an environment. Examples: plants and animals Soil
(organic matter) has both biotic and abiotic components.
Slide 20
+ Standard 6.L.2.3 Abiotic/Biotic Factors Refresher: What is
the difference between abiotic and biotic factors? What are
examples of each?
Slide 21
+ Different Environments Biomes: the world's major communities,
classified according to the predominant vegetation and
characterized by adaptations of organisms to that particular
environment. Biomes we will focus on: Freshwater, marine, forest,
grassland, tundra, desert Others include: tropical rainforest,
mountain, savannah and tundra
Slide 22
+ Aquatic Biomes: Freshwater & Marine Freshwater: Includes
streams, rivers, ponds and lakes Marine: covers about of the Earths
surface and includes oceans, coral reefs and estuaries
Slide 23
+ Forest Biome: Large assortments of trees, plants and animals
which vary depending on the zones climate
Slide 24
+ Grassland Biome An area that is populated mostly by grasses
and other non-woody plants
Slide 25
+ Desert Biome An area that received less than 25 centimeters
of rain a year
Slide 26
+ Tundra Biome Extremely cold and dry
Slide 27
+ Limiting Factors For Any Biome Environmental factors that
affect an organisms ability to survive in its environment, such as
food availability, predators, and temperature, are limiting
factors. A limiting factor is any biotic or abiotic factor that
restricts the existence, number, reproduction, or distribution of
organisms.
Slide 28
+ Limiting Factors Continued Can you think of a limiting factor
that would affect the organisms around Overhills?
Slide 29
+ One Example of Limiting Factors At high elevations, the wind
is too strong, temperatures too cold, and soil to thin to support
the growth of large trees. All that grows in this environment is
grasses, mosses, and ferns.
Slide 30
+ Limiting Factors Can Impact Multiple Species Example: water
is limited in a grassland area, reducing the number of seeds
produced. The rabbits depend on the grass for food. If there are
fewer seeds, theres less grass. Less grass= fewer rabbits. Hawks,
which feed on rabbits, have less food in return.