Grade 6 Ancient River Civilizations

GRADE 7

Science

Mrs. Donna Turbaczewski

Chapter 2 (text pages 34-53)

Populations I Communities I and Ecosystems

Students are introduced to individual populations within an Ecosystem.

They will explore the various populations within a community and identify how they interact with one another.
They will discover how energy from the sun becomes the source of energy for all living things.
They will distinguish among producers, consumers, and decomposers and how they are a part of a food chain and food webs.
This will be accomplished by reading, answering questions, discussion, and cooperative group work.

Organization levels of life, in a graphic format. Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.It is thus possible to study biology at many levels, from collections of organisms (communities), to the inner workings of a cell ( organelle).

Ecology

Individual organisms are grouped into populations, which in turn form communities, which form ecosystems. Ecosystems make up the biosphere, which includes all life on Earth. If there is life on other planets, will we need another level of organization?

Biosphere: The sum of all living things taken in conjunction with their environment. In essence, where life occurs, from the upper reaches of the atmosphere to the top few meters of soil, to the bottoms of the oceans. We divide the earth into atmosphere (air), lithosphere (earth), hydrosphere (water), and biosphere (life).

Ecosystem: The relationships of a smaller groups of organisms with each other and their environment. Scientists often speak of the interrelatedness of living things. Since, according to Darwin's theory, organisms adapt to their environment, they must also adapt to other organisms in that environment. We can discuss the flow of energy through an ecosystem from photosynthetic autotrophs to herbivores to carnivores.

Community: The relationships between groups of different species. For example, the desert communities consist of rabbits, coyotes, snakes, birds, mice and such plants as sahuaro cactus (Carnegia gigantea), Ocotillo, creosote bush, etc. Community structure can be disturbed by such things as fire, human activity, and over-population.

Species: Groups of similar individuals who tend to mate and produce viable, fertile offspring. We often find species described not by their reproduction (a biological species) but rather by their form (anatomical or form species).

Populations: Groups of similar individuals who tend to mate with each other in a limited geographic area. This can be as simple as a field of flowers, which is separated from another field by a hill or other area where none of these flowers occur.Individuals: One or more cells characterized by a unique arrangement of DNA "information". These can be unicellular or multicellular. The multicellular individual exhibits specialization of cell types and division of labor into tissues, organs, and organ systems.

Organ System: (in multicellular organisms). A group of cells, tissues, and organs that perform a specific major function. For example: the cardiovascular system functions in circulation of blood.

Organ: (in multicellular organisms). A group of cells or tissues performing an overall function. For example: the heart is an organ that pumps blood within the cardiovascular system.

Tissue: (in multicellular organisms). A group of cells performing a specific function. For example heart muscle tissue is found in the heart and its unique contraction properties aid the heart's functioning as a pump. .

Cell: The fundamental unit of living things. Each cell has some sort of hereditary material (either DNA or more rarely RNA), energy acquiring chemicals, structures, etc. Living things, by definition, must have the metabolic chemicals plus a nucleic acid hereditary information molecule.

Organelle: A subunit of a cell, an organelle is involved in a specific subcellular function, for example the

ribosome (the site of protein synthesis) or mitochondrion (the site of ATP generation in eukaryotes).

Molecules, atoms, and subatomic particles: The fundamental functional levels of biochemistry.

The Threatened Biosphere

The students will also focus on the conditions leading to ecological succession and the characteristics of successive biotic communities are also identified. The role that environmental disturbances (one example being fire) lead to succession is also explained.

Terms to know:

Population- a group of organisms that are all the same species. That's it. You're done. A group of ducks would not be a population if there were mallard and wood ducks combined. Scientists would say that there are two populations existing in the same area.

A Community is the set of all populations that inhabit a certain area. Communities can have different sizes and boundaries. These are often identified with some difficulty.

Ecosystem- The word ecosystem is short for ecological systems. An ecosystem includes all of the living organisms in a specific area.

Ecology - a science all by itself but it is also a branch of the larger sciences of biology and geography.

Immigration - In sociology, and biology, a population is the collection of people—or organisms of a particular species—living in a given geographic area.

Emigration - Individuals move (migrate) out of a population.

Birth rate - The ability of an organism's homeostatic mechanisms to allow it to survive the extremes of its environment determine its survival and reproduction. This is the basis of natural selection, and the success of individuals in an ecosystem determines the structure of the population in that ecosystem.

Limiting factors - In the natural world, limiting factors like the availability of food, water, shelter and space can change animal and plant populations. Other limiting factors like competition for resources, predation and disease can also impact populations.

Biotic potential - 1. "the inherent power of organisms to reproduce and survive" 2. " biotic potential of a species is a quantitative expression of the dynamic power of the species, which is pitted against the resistance of the environment in the struggle for existence" 3. Chapman (1931) "It is a sort of algebraic sum of the number of young produced at each reproduction, number of reproductions over a period of time, sex ratio of the species, and their general ability to survive under given physical conditions."

Predator - A predator is an animal or other organism (such as a carnivorous plant) that hunts and kills other organisms for food in an act called predation. Predators are either carnivores or omnivores

Parasitism - one organism (the parasite) benefits and the other (the host) is harmed. Parasitism can be considered a special case of predation since in both interactions one species acquires biomass directly from another. In cases where the parasite is specific to a single host, the interaction is symbiotic

Terms to know:

Niche - In ecology, a niche is a term describing the relational position of a species or population in an ecosystem. More formally, the niche includes how a population responds to the abundance of its resources and enemies (e. g., by growing when resources are abundant, and predators, parasites and pathogens are scarce) and how it affects those same factors (e. g., by reducing the abundance of resources through consumption and contributing to the population growth of enemies by falling prey to them). The abiotic or physical environment is also part of the niche because it influences how populations affect, and are affected by, resources and enemies.
Producers - Make their own food through photosynthesis or chemosynthesis and includes plants, algal protists, & some bacteria.
Consumers - heterotroph - Heterotrophs, like this eagle, feed off of other forms of life. This process of producing biological energy is different from that of autotrophs who produce their own food using energy from the sun. The term heterotroph can refer to single or multi-celled organisms. Many bacteria as well as all fungi and animals are heterotrophs.
Herbivores - A herbivore is an animal that gets its energy from eating plants, and only plants. Omnivores can also eat parts of plants, but generally only the fruits and vegetables produced by fruit-bearing plants. Many herbivores have special digestive systems that let them digest all kinds of plants, including grasses. Herbivores need a lot of energy to stay alive. Many of them, like cows and sheep, eat all day long. There should be a lot of plants in your ecosystem to support your herbivores.
Carnivores - Carnivora is the order of eutherian mammals that includes wolves, dogs, cats, raccoons, bears, weasels, hyaenas, seals, and walruses, to name just a few. Most carnivores are land animals, but an important and highly specialized group of carnivores, the pinnipeds or "fin-feet," have taken up life in the oceans; pinnipeds include seals, sea lions, and walruses. A few other carnivores, such as the sea otter, are also specialized for life in the oceans.
Omnivores - An omnivore is a kind of animal that eats either other animals or plants. Some omnivores will hunt and eat their food, like carnivores, eating herbivores and other omnivores. Some others are scavengers and will eat dead matter. Many will eat eggs from other animals.
Scavengers - Scavengers are animals that feed on dead or injured animals. Scavengers are not usually held in high esteem, but they have a job to do: they clean the earth of organic garbage.

Commensalisms - In ecology, commensalism is an interaction between two living organisms, where one creature benefits and the other is neither harmed nor helped. As with all ecological interactions, commensalisms vary in strength and duration from intimate, long-lived symbioses to brief, weak interactions through intermediaries.
Mutualism - Mutualism is any relationship between two species of organisms that benefits both species. This is the relationship most people think of when they use the word "symbiosis."
Habitats - Within each ecosystem, there are habitats which may also vary in size. A habitat is the place where a population lives. A population is a group of living organisms of the same kind living in the same place at the same time. All of the populations interact and form a community. The community of living things interacts with the non-living world around it to form the ecosystem. The habitat must supply the needs of organisms, such as food, water, temperature, oxygen, and minerals. If the population's needs are not met, it will move to a better habitat. Two different populations can not occupy the same niche at the same time, however. So the processes of competition, predation, cooperation, and symbiosis occur.

Terms to know:

Food chain - An ecosystem is a living community which depends on each member and its surrounding environment. The living part of an ecosystem is sometimes called a food chain.
Food web - Enough food webs have now been cataloged and described in detail for them to be studied as a general class of system using the techniques applied to the study of other networks. There are only a few descriptions of these studies outside the scientific literature. The California Academy of Sciences quarterly magazine - California Wild had this article called Untangled Food Webs and the BBC ran this story Life's not so complicated Web but beyond that there does not appear to be much out there.
Energy pyramid - On Photosynthesis; Food Chains starting with Photosynthesis; Energy in plants and animals; Our Friends the Plankton that do photosynthesis and the animals that eat them; how baleen whales skip a few steps to get closer to the phytoplankton level; how we humans manage to put ourselves into both marine and land food chains, and other extraordinary truths revealed.
On Photosynthesis; Food Chains starting with Photosynthesis; Energy in plants and animals; Our Friends the Plankton that do photosynthesis and the animals that eat them; how baleen whales skip a few steps to get closer to the phytoplankton level; how we humans manage to put ourselves into both marine and land food chains, and other extraordinary truths revealed.
Succession - is the observed process of change in the species structure of an ecological community over time. Within any community some species may become less abundant over some time interval, or they may even vanish from the ecosystem altogether. Similarly, over some time interval, other species within the community may become more abundant, or new species may even invade into the community from adjacent ecosystems. This observed change over time in what is living in a particular ecosystem is "ecological succession".
Primary succession - Ecological succession is the gradual process by which ecosystems change and develop over time. For example, a bare patch of ground will not stay bare. It will rapidly be colonized by a variety of plants
Climax communities - is an outdated ecological term for a community of plants and animals which is the result of succession, where a biological system, a community, or a soil has reached a steady state. The idea of a single climatic climax originates with Frederic Clements' idea of the ecological community as an organic superorganism in which the various stages of successional development could be seen as analogous with the ontological development of an organism. Clement's "monoclimax" theory was contrasted with Arthur Tansley's idea of the "polyclimax" which allowed for multiple steady-state end-points in a given climatic zone. Henry Gleason's opposition to climax theory saw him forced to the sidelines of the field of ecology. Terms such as pre-climax, post-climax, plagioclimax and disclimax were coined to account for the fact that many communities existed in states that diverged from what was expected to occur on the basis of climate.
Secondary succession - a fundamental concept in ecology, is the process by which a natural community moves from a simpler level of organisation to a more complex community. Succession is a natural process that occurs after some form or disturbance which simplifies the system. Ecological succession is usually differentiated into primary succession, which proceeds on a site in which no living material has survived the disturbance (e.g., on a lava flow or after a severe landslide), and secondary succession(Ecosystems undergo secondary succession following some artificial or natural disturbance such as a forest fire or farming. In 1850, Connecticut was almost entirely open land cleared for farming or timber. Today, Connecticut has been mostly reforested through the process of secondary succession as farming has left the state since the 1800's.) which occurs after some disturbance has disrupted the community, but has not eliminated all living components (e.g., after a fire or logging).
Trophic level refers to the organisms position in the food chain. Autotrophs are at the base. Organisms that eat autotrophs are called herbivores or primary consumers. An organism that eats herbivores is a carnivore and a secondary consumer. A carnivore which eats a carnivore which eats a herbivore is a tertiary consumer, and so on. It is important to note that many animals do not specialize in their diets. Omnivores (such as humans) eat both animals and plants. Further, except for some specialists, most carnivores don't limit their diet to organisms of only one trophic level. Frogs, for instance, don't discriminate between herbivorous and carnivorous bugs in their diet. If it's the right size, and moving at the right distance, chances are the frog will eat it. It's not as if the frog has brain cells to waste wondering if it's going to mess up the food chain by being a secondary consumer one minute and a quaternary consumer the next

Scientists discuss some general ecosystems. They call them biomes. A biome is a large area on the Earth's surface that is defined by the types of animals and plants living there. A biome can also be partially defined by the local climate patterns. You still might have more than one type of biome within a larger climate zone. Here is a short list of possible biomes.

Tropical Rainforest

Tropical Savanna

Desert

Coniferous Forest

Mediterranean Woodland

Mid-latitude Grassland

Mid-latitude Deciduous Forest

Tundra

Ice Caps

Click on the Picture Below -