Defining an Ecosystem

1. Defining an Ecosystem • Communities of organisms & their abiotic environment • Examples: • oak forest -intertidal zone • coral reef -a pond • Don’t have clear boundaries • Things move from one ecosystem to another. • Pollen can blow from a forest into a field, soil can wash from a mountain into a lake, & birds migrate from state to state.

2. The Components of an Ecosystem • Five basic components: • Energy • Minerals/Nutrients • Water • Oxygen • Living Organisms • Most energy comes from the sun • If one part of the ecosystem is destroyed or changes, the entire system will be affected.

3. Biotic and Abiotic Factors • Biotic factorsare environmental factors that are living organisms • plants, animals, dead organisms, & the waste products of organisms • Abiotic factorsare not associated with the activities of living organisms • air, water, rocks, temperature, salinity, pressure

4. Organisms • Organismsare living things that can carry out life processes independently. • Examples • You • Ants • Ivy • Bacteria • Species are groups of organisms that are closely related & can mate to produce fertile offspring. • Every organism is a member of a species.

5. Populations • Populations are groups of organisms of the same species that live in a specific geographical area & interbreed. • Example: • all the field mice in a corn field

6. Communities • Communitiesare groups of various species that live in the same habitat & interact with each other. • Every population is part of a community. • The most obvious difference between communities is the types of species they have.

7. Habitat • Place where an organism usually lives • Every habitat has specific characteristics that the organisms need to survive. If any of these factors change, the habitat changes. • Organisms are well suited to their natural habitats. • Animals & plants usually cannot survive for long periods of time away from their natural habitat.

8. Evolution by Natural Selection • Darwin observed that organisms in a population differ slightly in form, function, & behavior (some of these differences are hereditary). • Proposed that environment has a strong influence over which individuals survive to produce offspring • Darwin proposed that over many generations, natural selection causes the characteristics of populations to change. • Natural selectionis the process by which individuals that have favorable variations & are better adapted to their environment survive & reproduce more successfully than less well adapted individuals do. • Evolutionis a change in the characteristics of a population from one generation to the next. • Adaptation is the process of becoming adapted to an environment. It is an anatomical, physiological, or behavioral change that improves a population’s ability to survive.

11. Coevolution • The process of two species evolving in response to long-term interactions with each other is called coevolution. • Example: • Hawaiian honeycreeper, which has a long, curved beak to reach nectar at the base of a flower. The flower has structures that ensure that the bird gets some pollen on its head. • When the bird moves the next flower, some of the pollen will be transferred, helping it to reproduce. • The honeycreeper’s adaptation is along, curved beak. • The plant has two adaptations: • The first is the sweet nectar, which attracts the birds. • The second is the flower structure that forces pollen onto the bird’s head when the bird sips nectar.

12. Evolution by Artificial Selection • Artificial selectionis the selective breeding of organisms, by humans, for specific desirable characteristics. • Examples: • Dogs have been bred for certain characteristics. • Fruits, grains, & vegetables are also produced by artificial selection. Humans save seeds from the largest, & sweetest fruits. By selecting for these traits, farmers direct the evolution of crop plants to produce larger, sweeter fruit.

13. Evolution of Resistance • Resistanceis the ability of an organism to tolerate a chemical or disease-causing agent. • Examples: • An organism may be resistant to a chemical when it contains a gene that allows it to break down a chemical into harmless substances. • Humans promote the evolution of resistant populations by trying to control pests & bacteria with chemicals.

15. The Diversity of Living Things • 6 kingdoms based on different characteristics • Get food in different ways • made up of different types of cells • The cells of animals, plants, fungi, & protists all contain a nucleus (eukaryotes). Bacteria don’t (prokaryotes). • The cells of bacteria, fungi, & plants all have cell walls. Animals don’t.

16. 6 Kingdom Posters • Title-”Kingdom _____” • Number of Cells: unicellular, multicellular or both • Nutrition: autotrophic, heterotrophic or both • Cell Wall Present: yes or no • Habitat: describe where the organisms call live (terrestrial, aquatic, marine, etc.) • Examples: at least 3 examples

18. Bacteria • Extremely small, single-celled organisms that usually have a cell wall & reproduce by binary fission • Lack nuclei (prokaryotic) • 2 main kinds of bacteria: • archaebacteria (ancient bacteria) • Eubacteria (true bacteria) • Live in every habitat on Earth

19. Bacteria & the Environment • Some kinds of bacteria break down the remains & wastes of other organisms & return the nutrients to the soil. • Others recycle nutrients, like nitrogen & phosphorus. • Certain bacteria can convert nitrogen from the air into a form that plants can use. This conversion is important because nitrogen is the main component of proteins & genetic material. • Bacteria also allow many organisms, including humans, to extract certain nutrients from their food. • The bacterium, Escherichia coliorE. coli, is found in the intestines of humans & other animals & helps digest food & release vitamins that humans need.

20. Fungi • Cells have nuclei, rigid cell walls, & no chlorophyll • Mushroom=reproductive structure only • Most of fungus is underground network of fibers that absorb food from decaying organisms in the soil. • Fungi get food by releasing chemicals that help break down organic matter, & then absorbing the nutrients (heterotrophic). • Pros: decomposers, used to produce food products & some beverages • Cons: cause disease, rot buildings, cause food to spoil

21. Protists • Diverse organisms that belong to kingdom Protista. • “Junk-drawer” of classification • They are divided into three groups: • Plant like protists=ALGAE (autotrophs) • Animal like protists=PROTOZOANS (heterotrophs) • Fungus like protists=SLIME & WATER MOLDS (heterotrophs)

22. Plants • Plants are multicellular organisms that make their own food (autotrophs) & have cell walls. • Divided into 2 groups: • Nonvascular (no xylem or phloem) • Vascular (has xylem & phloem)

23. Nonvascular Plants • The first land plants had no vascular tissue, & swimming sperm. They therefore had to live in damp places & couldn’t grow very large. • Their descendents alive today are small plants such as mosses. • Ferns & club mosses were the first vascular plants, with some of the ferns being as large as small trees.

24. Vascular PlantsGymnosperms • Gymnospermsare woody vascular see plants whose seeds are not enclosed by an ovary or fruit. • Conifers (pine trees) are gymnosperms that bear cones. • Much of our lumber & paper comes from gymnosperms. • Adaptations allow them to live in drier conditions than lower plants • Produce pollen, which protects & moves sperm between plants • Produce seeds, which protect developing plants from drying out • Needle-like leaves also lose little water

25. Vascular PlantsAngiosperms • Angiospermsare flowering plants that produce seeds within fruit. Most land plants are angiosperms. • The flower is the reproductive structure of the plant. Some angiosperms, like grasses, have small flowers, that use wind to disperse their pollen. • Other angiosperms have large flowers to attract insects and birds. Many flowering plants depend on animals to disperse their seeds & carry their pollen. • Most land animals are dependent on flowering plants. • Most of the food we eat, such as wheat, rice, beans, oranges, & lettuce comes from flowering plants. • Building materials and fibers, such as oak & cotton, also come from flowering plants.

26. Animals • Can’t make their own food (heterotrophic) • Animal cells have no cell walls, making their bodies soft & flexible. Some animals have evolved hard exoskeletons. • Animals are more mobile than plants. All animals move around in their environment during at least one stage in their lives. • Divided into 2 groups: • Invertebrates (no backbone) • Vertebrates (have a backbone)

27. Invertebrates • No backbones • More insects exist on Earth than any other type of animal. • Insects are successful for many reasons: they have a waterproof skeleton, can move & reproduce quickly, most insects can fly, & their small size allows them to live on little food & to hide from enemies in small places.

28. Vertebrates • Have a backbone • mammals, birds, reptiles, amphibians, & fish • 1st were fish, but most live on land now • 1st LAND vertebrates were reptiles (ectotherms). • Birds are warm-blooded with feathers. • Mammals are warm-blooded vertebrates that have fur & feed their young milk. • Birds & mammals have the ability to maintain a high body temperature which allows them to live in cold areas (endotherms).

29. List the 6 kingdoms of living organisms. • The Chihuahua is a dog that exists because of _________ selection. • Fungi and bacteria are important to the environment because they _________. • Phytoplankton are important protists because they are a source of _________ & _________.