Download Skill Builder _5 Introduction to Ecology 25 Feb 2014

Biology I
Mr. Salvitti
Name:
Per/Date:
Skill Builder #5: Introduction to Ecology
I. Background:
The Sixth Mass Extinction: As the human population has increased, many other species have declined in
number or became extinct. For example, on the Hawaiian Islands, where isolation fostered the evolution of a
diverse and unique set of species, 60 of the 100 species of native birds have disappeared since the first
human colonists arrived. They were eliminated by habitat destruction, overhunting, and introduced diseases
and predators. Worldwide, about 20 percent of the species of birds have become extinct in the last 2,000
years. Today extinction is occurring most rapidly in the tropics. Paleontologists have found evidence in the
fossil record of five major mass extinctions, episodes in which a large percentage of Earth’s species
became extinct in a relatively short time. The five extinctions of the past, where a result of natural biologic
and climatic causes. The sixth mass extinction which is happening now is a result of human activities on the
planet. Currently, species are disappearing faster than at any time since the last mass extinction—the
disappearance of the dinosaurs 65 million years ago. Scientists estimate that about one-fifth of the species in
the world may disappear in just this next century.
Ecology is the study of the interactions between organisms and the living (biotic) and nonliving (abiotic)
components of their environment. The Earth includes a tremendous variety of living things. Each organism
depends in some way on other living and nonliving things in its environment. Ecology involves collecting
information about organisms and their environments, looking for patterns, and seeking to explain these
patterns.
Today’s Environment: Although the field of ecology was not named until 1866, ecological information
and understanding have always been crucial to humans and our survival. Before the development of
agriculture about 10,000-12,000 years ago, our ancestors obtained all of their food by hunting and gathering
grains, seeds, berries, nuts, roots, and plants. For them survival depended on practical knowledge about the
environment. While our understanding of the environment has grown much more sophisticated, our need for
information has grown more urgent. Over the past few decades, humans have changed the environment on a
greater scale than ever before in history. Learning how to improve our effect on the environment is critical
to the survival of our species and the planet.
The biosphere is the portion of Earth that supports life. It includes our atmosphere (air), lithosphere
(landmasses), hydrosphere (bodies of freshwater and saltwater), and locations below the Earth’s surface
that supports life. Biotic Factors are all of the living things in an organism’s environment. Abiotic Factors
include all of the nonliving things in an organism’s environment. Examples are temperature, air currents,
sunlight, rainfall, soil type and available nutrients. No single organism is isolated!! The interconnectedness
or interdependence of all organisms is central to the study of ecology. The survival of organisms depends
on their interactions with their surrounding environment Example: Humans cannot live without the plants
that produce food and oxygen. Biosphere: is the broadest and most inclusive level of organization. The
Earth and its atmosphere make up our biosphere. It extends from 8 to 10 km (5-6 miles) above the
Earth’s surface, to the deepest parts of the ocean. The biosphere is comprised of smaller units called
ecosystems. Ecosystems: include all of the organisms, and the abiotic environment found in a specific
place. Example: pond ecosystem-- Abiotic components: water temperature (Temp.), amount of dissolved
oxygen (D.O.) and carbon dioxide (CO2), the pH level (acid or basic, 0-14). Biotic components: insects,
fish, algae, aquatic plants, turtles. Some ecosystems can also be considered a habitat of an organism. A
niche, is the role an organism plays in its environment. It includes: Range of conditions the organism can
tolerate; Methods by which it obtains resources; and interactions with its environment such as reproduction.
1
Biology I
Mr. Salvitti
Name:
Per/Date:
A community is all of the interacting organisms living in an area. Examples: All of the fish, turtles, insects,
plants and algae make up the community of a pond.
Competition occurs when more than one organism uses a resource at the same time. Ex: Lions and
hyenas compete for the same food sources. Predation is the act of one organism consuming another for
food. Most species survive because of relationships called symbiosis—a close and often long-term
interaction between two or more different biological species. Examples: Mutualism: is when both
organisms benefit. Ex: The Egyptian plover takes insects from the backs of buffaloes, giraffes and rhinos.
Commensalism: One benefits; the other is not affected. Ex: Sea anemone and the clown fish. Parasitism:
One benefits at the expense of the other. Ex: Deer tick and mammal.
Energy in an Ecosystem: Ecosystems are most often thought of or measured in terms of energy
production and energy flow. In an ecosystem the ultimate source of energy is the sun. Autotrophs: Are
primary producers that make their own food. They use energy from sunlight or inorganic substances. They
are the foundation of all ecosystems, and they make energy available for all of the other organisms to use.
Ex: Plants. Heterotrophs: on the other hand, get their energy by consuming other organisms. They are
referred to as “consumers.” Herbivores eat only plants or herbaceous food. Example: Deer. Carnivores eat
other animals or meat. Example: Lions. Omnivores eat both plants and animals, and most anything they
can find. Examples: bears and raccoons. Detrivores eat dead/decaying material. Example: Earth worms.
Decomposers are similar to detrivores break down dead organisms by releasing digestive enzymes. Ex:
fungi such as mushrooms. Decomposers are important because they make nutrients available for all other
organisms.
Trophic levels: Each step in a food chain or food web is referred to as a trophic level (food or feeding
level). Autotrophs are the first trophic level in ALL food chains and food webs and are considered primary
producers. Primary producers: make their own food. Plants are considered primary producers. Primary
consumers: eat the primary producers. Secondary consumers: eat the primary consumers. Third-level
consumers: eat the secondary consumers. Energy flows upward from the primary consumer to the third
level consumer. Since primary consumers are considered the foundation of food webs and chains there are
more of them than any other trophic level above. As the levels go up each level have less numbers of
individuals and less energy to pass on. Food chains: are a simple model that shows how energy flows
through an ecosystem. Arrows show one-way energy flow in the chain or system. Each organism uses
some of the energy from the organism it eats. The remaining energy is lost to the surrounding
environment. Food webs: are models that represent the interconnected food chains in which energy
flows through a group of organisms. An ecological pyramid: is diagrams that show the relative amounts
of energy, biomass or numbers of organisms at each trophic level. Biomass is the total mass of living
matter at each trophic level. This includes all the plants and animals that live there. Approximately 90% of
all energy at a tropic level is NOT transferred to the level above it.
II. Identification:
1. Levels of Organization
2. An Ecosystem
2
Biology I
Mr. Salvitti
3. A community
Name:
Per/Date:
4. Mutualism
Birds
5. Food Chains
6. Food Web
7. Energy Pyramid
3
Biology I
Mr. Salvitti
Name:
Per/Date:
III. Assessment:
1. The first mass extinction occurred during the Ordovician Period around 490 millian years ago, followed
by the Devonian Pd 417 mya, then the Permian Pd 290 mya, followed by the Triassic Pd 245 mya, and then
the Cretaceous Pd 144 mya. When did the last mass extinction occur? Why? _________________________
_______________________________________________________________________________________
2. What is the science of ecology? ___________________________________________________________
_______________________________________________________________________________________
3. The Biosphere includes: _________________________________________________________________
_______________________________________________________________________________________
4. What is the diffedence between biotic and abiotic? ____________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
5. When a farmer measures the pH of the soil before planting a crop of soy beans which type of factor is he
analyzing boitic or abiotic? ________________________________________________________________
6. When more than one organism uses a resource at the same time such as lions and hyenas competing for
the same food biologist refer to this as: _______________________________________________________
7. Decomposers are important because: _______________________________________________________
_______________________________________________________________________________________
8. The ultimate energy source in an ecosystem is: _______________________________________________
_______________________________________________________________________________________
9. What biotic factor is considered to be the foundation of an ecosystem in terms of energy flow? Explain. _
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
10. CRITICAL THINKING: Based on your limited understanding of ecology and the biosphere, why is it
important for high school students in Pennsylvania to study the effects that global warming has on the loss
of Polar Bears in the Arctic, or the disappearance of amphibians in South America? ___________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
4