The California Life Science Standards for elementary school children are organized in a very sequential way, with concepts at each grade level building upon concepts introduced at earlier levels and in an age-appropriate fashion. As you read through this introduction, you may find it useful to also have a copy of the standards to look at... pay attention to how the standards were selected and edited.
An example of the sequencing of life science standards can be illustrated in the context of the concepts that were introduced on the class field trip to the Fort Ord BLM lands where we studied vernal pools and maritime chaparral ecosystems.
| GRADE | ABREVIATED RELEVANT STANDARDS | Maritime Chaparral and the K-6 Life Science Standards | |||||||||||||||||||||||||||||||||
| K | 2.
Different types of plants inhabit the earth. (a) Students know how to observe and describe similarities and differences in the appearance of plants. |
By the end of Kindergarten we want children to be able to describe the differences between the leaves of coast live oak and chamise, and yet notice that the leaves of chaparral plants are small, and usually hard and scratchy, not soft like running through a field of grass or large like their house plants. We might also want them to notice that chaparral is hard for people to walk through, and that cowboys wore "chapas" on their legs when riding through chaparral. | |||||||||||||||||||||||||||||||||
| 1st | 2.
Plants meet their needs in different ways. (a) Students know different plants inhabit different kinds of environments and have external features that help them thrive in different kinds of places. (b) Students know plants need water and light. (c) Students know roots are associated with the intake of water and soil nutrients and green leaves are associated with making food from sunlight. |
Plants need water and light. Students learn that leaves are used to gather energy from the light. They also learn that plants use roots to get the water they need. Because they have to go so many months without rain, chaparral plants have strong roots that go deep into the soil to find the water that they need. | |||||||||||||||||||||||||||||||||
| 2nd | 2.
Plants and animals have predictable life cycles. (e) Students know light, gravity, touch, or environmental stress can affect the germination, growth, and development of plants. (f) Students know flowers and fruits are associated with reproduction in plants. (g) Students know that soil is made partly from weathered rock and partly from organic materials and that soils differ in their color, texture, capacity to retain water, and ability to support the growth of many kinds of plants. |
Plants that can't resprout after fire or whose seeds can't tolerate high temperature don't do well in chaparral ecosystems, although some plants whose seeds can blow in from great distances or are brought in by animals do manage to be part of the community. Only plants who have features that allow them to tolerate dry, nutrient poor soils, strong salty ocean winds, and fire, are members of the maritime chaparral plant community. | |||||||||||||||||||||||||||||||||
| 3rd | 2.
Adaptations in physical structure or behavior may improve an
organism's chance for survival. (a) Students know plants have structures that serve different functions in growth, survival, and reproduction. (b) Students know examples of diverse life forms in different environments, such as oceans, deserts, tundra, forests, grasslands, and wetlands. (c) Students know living things cause changes in the environment in which they live: some of these changes are detrimental to the organism or other organisms, and some are beneficial. (d) Students know when the environment changes, some plants survive and reproduce; others die. |
I think scientists chose a very confusing word to descibe properties of organisms that help them survive in a given environment. The white fur of a polar bear allows it to lie undetected on the ice at the edge of a breathing hole and catch seals. Polar Bears are a relatively new bear having appeared during the last set of ice ages, and are descended from an ancestor to Brown and Grizzly Bears. The hypothesis is that during the thousands of years the earth was gripped by a series of ice ages, those northern brown bears with lighter fur attempting to catch seals at the edge of the ice did better and produced more offspring than those with darker fur. Conversly, a white polar bear would not do well attempting to catch seals on the coast of California the way Grizzlies did until they were wiped out. In fact, scientists are predicting that Polar Bears may become extinct with global warming and their former range taken over by Grizzlies. The white fur is a property of Polar Bears that is advantageous in a white environment. Scientists call such a property an "adaptation." It is a heritable and variable character that is selected by increased survival rates over many generations in a population of organisms. I use the example of the white fur of Polar Bears because it is a quick and easy introduction to understanding adaptation. It can be harder for children to understand more subtle adaptations such as volatile flammable oils and root crown sprouting. These are two major adaptations common in chaparral plants. The first actually promotes fire and the second speeds recovery from fire disturbance. Look at standards 2(c) and 2(d) and think about how they relate to the dynamics of chaparral ecosystems. |
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| 4th | 2.
All organisms need energy and matter to live and grow. (a) Students know plants are the primary source of matter and energy entering most food chains. (b) Students know producers and consumers (herbivores, carnivores, omnivores, and decomposers) are related in food chains and food webs and may compete with each other for resources in an ecosystem. (c) Students know decomposers, including many fungi, insects, and microorganisms, recycle matter from dead plants and animals. 3. Living organisms depend on one another and on their environment for survival. (a) Students know ecosystems can be characterized by their living and nonliving components. (b) Students know that in any particular environment, some kinds of plants survive well, some survive less well, and some cannot survive at all. (c) Students know many plants depend on animals for pollination and seed dispersal. |
The set of standards for Fourth Grade Life Science are not as difficult conceptually as adaptation but they are daunting because of the amount of material that has to be taught. Fifth grade is when the students get their first statewide science assessment, so fourth grade science is very important. Fifth Grade Life Science is also highly focused on human biology, so they will have to remember ecology for almost a year before being tested on it The overarching key ideas in Fourth Grade are competition for limited resources, the interdependence of organisms, energy dependence and flow in ecosystems, and nutrient cycling. Water is the main limiting factor in Maritime Chaparral and lack of nutrients is a close second. All the plants are competing with each other for water, and have adaptations that help them survive the long yearly drought. There are also many interdependencies... we saw the example of Sticky Monkey Flower being dependent on humming birds for pollination, but there are many others we haven't covered yet. Below I will cover the basic flow of energy in the chaparral ecosystems, and we already know that fire is the main way nutrients are recycled in chaparral ecosystems. |
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| 5th | Fifth grade is devoted to plant and animal anatomy and physiology. | There is one standard and subtopic that could be related to our field trip, but I did not cover it, nor would it have been well illustrated on that fieldtrip. | |||||||||||||||||||||||||||||||||
| 6th | 5.
Organisms in ecosystems exchange energy and nutrients among themselves
and
with the environment. (a) Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs. (b) Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment. (c) Students know populations of organisms can be categorized by the functions they serve in an ecosystem. (e) Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition. |
It takes a tremendous amount of energy to strip the hydrogens off of water molecules and add them to carbon dioxide molecules to make carbohydrates. In almost every ecosystem known, primary producers perform this reaction using sunlight. Producers (autotrophs) form a starting point for the food web which passes the captured solar energy back and forth between trophic levels in the form of "food." Each trophic level has a name, for example, producer, primary consumer, secondary consumer, or decomposer. But often, things are more complicated than indicated in this scheme. Plants are the producers in the maritime chaparral ecosystem. A typical food chain within the food web might be:
"Food web" is the more appropriate term, because many animals die of starvation or disease without being eaten by a predator, and of course most biomass leaves plants as leaf litter or dead wood in the form of roots and dry stems. Many animals are generalists, like humans and crows, and feed at more than one trophic level. And most interesting of all, some animals switch places on the food chain as they mature from juvenile to adult. So Herons that might be preyed upon by snakes as hatchlings, later become a predator of snakes as adults. Finally, don't forget that decomposers are eaten by other organisms as well... are those organisms primary or secondary consumers??? Ceanothus is dominant member of the Maritime Chaparral ecosystem (it was at the first stop but I forgot to mention it). If I had remembered to show them to you, you would have seen two species Ceanothus papillosus and Ceanothus thyrsiflorus. As a producer, Ceanothus is very important to the chaparral ecosystem because of its ability to form a symbiotic relationship to a soil fungus called Frankia. When the roots of Ceanothus and the fungus combine, the roots supply the fungus with sugar. This extra energy source stimulates the fungus to fix nitrogen from the atmosphere to make ammonia and amino acids, a process even more energy intensive than making carbohydrates. Usable nitrogen is in extremely short supply in maritime chaparral soils, so the fact that Ceanothis has its own source of fertilizer makes it very competitve, especially in the first years after a fire. Later, as primary consumers eat the leaves, or the leaf litter is decomposed by decomposers, nitrogen becomes available in the soil to other plants and Ceanothus starts to lose its competitive edge. |
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 Spined Soldier Bug (Hemiptera) |
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