The document provides information on the organization of life on the planet by defining key terms: - Organism, population, community, and ecosystem describe increasing levels of biological organization, from individual to multiple interacting species and environments. - Communities consist of interacting populations in the same area and involve predation, competition, and symbiosis between species. Predation regulates populations while competition and symbiosis shape species evolution. - Biomes are large ecosystems defined by climate and habitat, such as forests, grasslands, and deserts. Biomes contain many interconnected communities of species.

1. Topic: Organization of life in the planet

2. The organization of life in the planet

4. ORGANISM
• A form of life considered as an entity; an
animal, plant, fungi, protist, or moneran.
• Any organized body or system conceived as
a living being
• A form of life composed of mutually
interdependent parts that maintain various
vital processes.

5. POPULATION
• A population is a summation of all the
organisms of the same group or species,
which live in a particular geographical area,
and have the capability of interbreeding

6. COMMUNITY
• A community is an assemblage or association
of populations of two or more different
species occupying the same geographical area
and in a particular time.

7. ECOSYSTEM
• An ecosystem is a community of living
organisms in conjunction with the nonliving
components of their environment (things like
air, water and mineral soil), interacting as a
system

8. Topic: Community Interactions

10. If you saw the movie Finding Nemo, then you probably recognize
this fish. It’s known as a clownfish, and it’s swimming near the
tentacles of an animal called a sea anemone. The sea anemone
kills prey by injecting poison with its tentacles. For some reason,
the anemone doesn’t harm the clownfish, perhaps because the
fish has a coating of mucus that helps disguise it.
But why does the clownfish “hang out” with the sea anemone?
• One reason is for the food. The clownfish eats the remains of
the anemone’s prey after it finishes feeding.
• Another reason is safety. The clownfish is safe from predators
when it’s near the anemone. Predators are scared away by the
anemone’s poison tentacles. In return, the clownfish helps the
anemone catch food by attracting prey with its bright colors.
Its feces also provide nutrients to the anemone.
• The clownfish and anemone are just one example of the
diverse ways that living things may help each other in nature

11. Community Interactions
Biomes as different as deserts and wetlands
share something very important. All biomes
have populations of interacting species. Species
also interact in the same basic ways in all
biomes.
For example, all biomes have some species that
prey on others for food. The focus of study of
species interactions is the community.

12. What Is a Community?
A community is the biotic part of an ecosystem. It
consists of all the populations of all the species in
the same area.
It also includes their interactions. Species
interactions in communities are important factors in
natural selection.
They help shape the evolution of the interacting
species. There are three major types of community
interactions: predation, competition, and symbiosis.

13. Predation
• Predation is a relationship in which members of one
species (the predator) consume members of another
species (the prey). The lions and zebras are classic
examples of predators and prey.
• In addition to the lions, there is another predator in
this figure. Can you spot it? The other predator is the
zebra. Like the lions, it consumes prey species, in this
case species of grass. However, unlike the lions, the
zebra does not kill its prey. Predator-prey relationships
such as these account for most energy transfers in food
chains and food webs.

15. Predation and Population
• A predator-prey relationship tends to keep the
populations of both species in balance. As the prey
population increases, there is more food for predators.
So, after a slight lag, the predator population increases
as well. As the number of predators increases, more
prey are captured. As a result, the prey population
starts to decrease. What happens to the predator
population then?
• In the predator-prey example, one factor limits the
growth of the other factor. As the prey population
decreases, the predator population begins to decrease
as well. The prey population is a limiting factor. A
limiting factor limits the growth or development of an
organism, population, or process.

17. Keystone Species
• A keystone species is one that plays an
especially important role in its community.
• It has a disproportionate effect on the
structure of an ecological community.
• Major changes in the numbers of a keystone
species affect the populations of many other
species in the community.
• Some predator species are known as keystone
species.

18. • For example, some sea star species are keystone
species in coral reef communities. The sea stars
prey on mussels and sea urchins, which have no
other natural predators.
• If sea stars were removed from a coral reef
community, mussel and sea urchin populations
would have explosive growth.
• Star fish avoid species at lower trophic levels
from monopolizing critical resources, such as
competition for space or key producer food
sources

20. Adaptations to Predation
• Both predators and prey have adaptations to
predation that evolve through natural
selection. Predator adaptations help them
capture prey. Prey adaptations help them
avoid predators. A common adaptation in
both predator and prey is camouflage.
• Camouflage in prey helps them hide from
predators. Camouflage in predators helps
them sneak up on prey.

21. Can you see the crab in the photo on
the left? It is camouflaged with
the sand. The preying mantis in the
middle photo looks just like the dead
leaves in the background. Can you tell
where one zebra ends and another
one begins? This may confuse a
predator and give the zebras a chance
to run away.

22. Carrying Capacity (K)
• It is the maximum population size of a species that can
sustain infinitely in an environment, provided that
food, water, habitat, and other factors are maintained.
It is also known as the maximal load of the
environment.
• Every organism belongs to an ecological niche. A niche
can be described as a functional relationship an
organism has with its biotic and abiotic environment. It
may include various physical factors (like temperature,
humidity, soil), biotic components (like prey,
predators), and the behavioral aspect of the organism
as well as the organisms that surround it.

23. • Individuals that inhabit the same ecological
niche require almost the same resources for
their survival. As these resources may be
limited, it gives rise to a continuous struggle
between its inhabitants. This struggle is aptly
called competition (as individuals compete
with one another)

24. Competition
Competition is a relationship between
organisms that struggle for the same resources
in the same place. The resources might be food,
water, or space.
There are two different types of competition:
• Intraspecific competition
• Interspecific competition

25. Intraspecific competition occurs between members of the same
species. This type of competition is a basic factor in natural selection.
It leads to the evolution of better adaptations within a species.

26. Interspecific competition occurs between members of different
species.

27. Interspecific Competition and
Extinction
• Interspecific competition often leads to
extinction. The species that is less well
adapted may get fewer of the resources that
both species need. As a result, members of
that species are less likely to survive, and the
species may go extinct.

28. Interspecific Competition and
Specialization
• Instead of extinction, interspecific competition
may lead to greater specialization.
Specialization occurs when competing species
evolve different adaptations.
• For example, they may evolve adaptations
that allow them to use different food sources.

29. Specialization in Anole Lizards: Specialization lets different species of anole
lizards live in the same area without competing.

30. Symbiosis
• Symbiosis is a close relationship between two
species in which at least one species benefits.
For the other species, the relationship may be
positive, negative, or neutral.
There are three basic types of symbiosis:
• Mutualism
• Commensalism
• Parasitism

31. Mutualism
• Mutualism is a symbiotic relationship in which both
species benefit.
• An example of mutualism involves goby fish and
shrimp. The nearly blind shrimp and the fish spend
most of their time together. The shrimp maintains a
burrow in the sand in which both the fish and shrimp
live. When a predator comes near, the fish touches the
shrimp with its tail as a warning. Then, both fish and
shrimp retreat to the burrow until the predator is gone.
From their relationship, the shrimp gets a warning of
approaching danger. The fish gets a safe retreat and a
place to lay its eggs.

32. The
multicolored
shrimp in the
front and
the green goby
fish behind it
have a
mutualistic
relationship.

33. Commensalism
• Commensalism is a symbiotic relationship in
which one species benefits while the other
species is not affected. One species typically
uses the other for a purpose other than food.
For example, mites attach themselves to
larger flying insects to get a “free ride.” Hermit
crabs use the shells of dead snails for homes.

35. Parasitism
• Parasitism is a symbiotic relationship in which one species
(the parasite) benefits while the other species (the host) is
harmed. Many species of animals are parasites, at least
during some stage of their life. Most species are also hosts
to one or more parasites.
• Some parasites live on the surface of their host. Others live
inside their host. They may enter the host through a break
in the skin or in food or water. For example, roundworms
are parasites of mammals, including humans, cats and
dogs.
• The worms produce huge numbers of eggs, which are
passed in the host’s feces to theenvironment. Other
individuals may be infected by swallowing the eggs in
contaminated food or water.

36. Roundworm. A roundworm like this
one might eventually fill a dog’s
intestine unless it gets medical
treatment.
Some parasites kill their host, but
most do not. It’s easy to see why. If
a parasite kills its host, the parasite
is also likely to die. Instead,
parasites usually cause relatively
minor damage to their host

37. Ecological Succession
Communities are not usually static. The numbers and types of
species that live in them generally change through time. This is
called ecological succession. Important cases of succession are
primary and secondary succession.
Primary Succession
Primary succession occurs in an area that has never before been
colonized. Generally, the area is nothing but bare rock. This type
of environment may come about when
• A lava flows from a volcano and hardens into rock.
• A glacier retreats and leaves behind bare rock.
• A landslide uncovers an area of bare rock.

38. • The first species to colonize a disturbed area such
as this are called pioneer species
• They change the environment and pave the way for
other species to come into the area. Pioneer
species are likely to include bacteria and lichens
that can live on bare rock. Along with wind and
water, they help weather the rock and form soil.
• Once soil begins to form, plants can move in. At
first, the plants include grasses and other species
that can grow in thin, poor soil. As more plants
grow and die, organic matter is added to the soil.
This improves the soil and helps it hold water. The
improved soil allows shrubs and trees to move into
the area.

40. Secondary Succession
• Secondary succession occurs in a formerly
inhabited area that was disturbed. The
disturbance could be a fire, flood or human
action such as farming. This type of succession is
faster because the soil is already in place. In this
case, the pioneer species are plants such as
grasses, birch trees, and fireweed.
• Organic matter from the pioneer species
improves the soil. This lets other plants move into
the area.

42. CLASSWORK
Work in pairs and solve the following questionaire in your notebooks:
Write true if the statement is true and false if the statement is false.
1. Species interact in the same basic ways in all biomes.
2. Types of community interactions include symbiosis.
3. Predation always involves one animal consuming another animal.
4. If the population of a prey species increases, the population of its predator is
likely to decrease.
5. Some prey species have adaptations that make them more visible to
predators.
6. Interspecific competition always leads to the extinction of one of the
species.
7. Predation is an example of a symbiotic relationship.
8. A mosquito and the animal from which it takes blood have a mutualistic
Relationship.
9. Many plants and fungi are parasitic during some stages of their life cycle.
10. The species that is harmed in a parasitic relationship is called the host.
11. Most ecosystems are stable and unchanging.
12. Primary succession usually occurs faster than secondary succession.

43. ECOSYSTEM
• Each individual plant and animal could not exist by
itself on planet Earth. All living organisms need millions
of other living organisms to survive. How these
organisms interact with the sun, soil, water, air and
each other in a specific area is called an ecosystem.
• An ecosystem describes a specific area where the
organisms work together as a unit. It could be any size
from a tiny pool of water to hundreds of square miles
of desert. Each ecosystem is different and each has
established a balance over time that is important to
every form of life within the ecosystem.

44. The Balance of the Ecosystem
Ecosystems maintain important
balances in order that all the
organisms within the ecosystem
can survive. These balances
involve food, water, oxygen,
nitrogen, and carbon.
The sun provides the energy
needed by ecosystems. Plants
take this energy and use
photosynthesis to create sugar
which they can use for energy.
Nutrients in the soil, the air, and
water also play a part in keeping
an ecosystem thriving and in
balance.
Some important cycles that
occur in ecosystems to help
maintain proper balance include:
• Food Chain and Food Web
(Energy Cycle)
• Carbon Cycle
• Oxygen Cycle
• Water Cycle
• Nitrogen Cycle

45. BIOME
• A biome is way to describe a large group of similar
ecosystems. Biomes have similar weather, rainfall,
animals, and plants. There are a number of biomes
on planet Earth.
• The map of the world biomes is shown below.

46. BIOMES
LAND BIOMES
• Desert
• Grasslands
• Savanna
• Tundra
• Tropical Rainforest
• Temperate Forest
• Taiga Forest
AQUATIC BIOMES
• Marine
• Freshwater
• Coral Reef

47. Topic: Biomes and biosphere

48. ATMOSPHERE
• The atmosphere contains all the air in Earth's system. It
extends from less than 1 m below the planet's surface
to more than 10,000 km above the planet's surface.
• The upper portion of the atmosphere protects the
organisms of the biosphere from the sun's ultraviolet
radiation. It also absorbs and emits heat. When air
temperature in the lower portion of this sphere
changes, weather occurs.
• As air in the lower atmosphere is heated or cooled, it
moves around the planet. The result can be as simple
as a breeze or as complex as a tornado.

49. HYDOSPHERE
• The hydrosphere contains all the solid, liquid, and gaseous
water of the planet. It ranges from 10 to 20 kilometers in
thickness. The hydrosphere extends from Earth's surface
downward several kilometers into the lithosphere and
upward about 12 kilometers into the atmosphere.
• A small portion of the water in the hydrosphere is fresh
(non-salty). This water flows as precipitation from the
atmosphere down to Earth's surface, as rivers and streams
along Earth's surface, and as groundwater beneath Earth's
surface. Most of Earth's fresh water, however, is frozen.

50. • Ninety-seven percent of Earth's water is salty. The salty
water collects in deep valleys along Earth's surface. These
large collections of salty water are referred to as oceans. The
image above depicts the different temperatures one would
find on oceans' surfaces. Water near the poles is very cold,
while water near the equator is very warm.
• The differences in temperature cause water to change
physical states. Extremely low temperatures like those found
at the poles cause water to freeze into a solid such as a polar
icecap, a glacier, or an iceberg. Extremely high temperatures
like those found at the equator cause water to evaporate
into a gas.

51. LITOSPHERE
• The lithosphere contains all of the cold, hard solid land of the
planet's crust (surface), the semi-solid land underneath the crust,
and the liquid land near the center of the planet. The surface of the
lithosphere is very uneven There are high mountain ranges like the
Rockies and Andes huge plains or flat areas like those in Texas, Iowa,
and Brazil and deep valleys along the ocean floor
• The solid, semi-solid, and liquid land of the lithosphere form layers
that are physically and chemically different. If someone were to cut
through Earth to its center, these layers would be revealed like the
layers of an onion. The outermost layer of the lithosphere consists of
loose soil rich in nutrients, oxygen, and silicon. Beneath that layer
lies a very thin, solid crust of oxygen and silicon. Next is a thick, semi-
solid mantle of oxygen, silicon, iron, and magnesium. Below that is a
liquid outer core of nickel and iron. At the center of Earth is a solid
inner core of nickel and iron.

52. BIOSPHERE
• The biosphere contains all the planet's living things. This sphere
includes all of the microorganisms, plants, and animals of Earth.
Within the biosphere, living things form ecological communities
based on the physical surroundings of an area. These communities
are referred to as biomes. Deserts, grasslands, and tropical
rainforests are three of the many types of biomes that exist within
the biosphere.
It is impossible to detect from space each individual organism
within the biosphere. However, biomes can be seen from space. For
example, the image above distinguishes between lands covered
with plants and those that are not