Transcript Week 3
Turbo TAKS Week 3 Lesson 1: Plants Lesson 2: Energy Flow in Ecosystems Lesson 3: Evolution and Adaptations Lesson 4: Viruses and Bacteria Lesson 1: Plants Photosynthesis Review 6CO2 + 6H2O C6H12O6 + 6O2 Plants convert solar energy into useable chemical energy (sugar) Since plants make their own food, they are AUTOTROPHIC! Occurs in the chloroplasts Leaf Structures Leaves absorb energy from the sun (Broader/ bigger leaves absorb more sunlight!) Epidermis- covers the upper and lower surfaces and secretes a waxy coating called a cuticle Veins- vascular tissues (like the circulatory system) of the plant and run from the leaves through the stems and the roots to supply leaf cells with water and nutrients Phloem: takes sugars down, remember “Phlo low” Xylem: brings water up, remember “Xy high” Stomata/ stoma- allow gases (CO2 and O2) in and out of the cell Transpiration Transpiration – loss of water vapor from a plant If a plant has adequate water, water exerts turgor pressure against cell walls If a plant loses too much water, cells lose water and become flaccid, and the plant wilts Stomata let CO2 in and control water loss Each stomata is surrounded by guard cells When plants have plenty of water, stomata open and CO2 can diffuse into the leaf When plants lose too much water, guard cells become flaccid and stomata close – this prevents more water loss Stems and Roots Stems for conduction Phloem- transports sap containing sugars and amino acids through the cytoplasm in the tube Xylem- transports water from the roots to the leaves Roots for water absorption Fibrous root system: has many branching roots and are usually close to the surface which helps prevent erosion, like corn and beans Taproot system: roots penetrate into deep soil and are usually long and slender with short side branches, like oak and carrots Lesson 2: Energy Flow Through Ecosystems Physical Aspects in an Ecosystem BIOTIC FACTORS Bio means “life” Living organisms Ex: plants, animals ABIOTIC FACTORS “a” means “not” Non-living things Ex: rocks, wind, sun, water, dirt Symbiotic Relationships Mutualism: both partners benefit Commensalism: one partner benefits and the other partner is not affected Parasitism: one partner benefits and the other is harmed Predatory: predator/prey - one organism eats the other Wheat Mouse Snake A food chain shows one path energy can take A food web is a collection of several food chains, linked together Owl Trophic Levels = feeding level Producers are at the bottom, they make their own food Primary consumers eat producers (herbivores) Secondary consumers eat primary consumers (carnivores) 10 % Rule Only 10 % of the energy at one trophic level is passed on to the next 90% is lost as heat The greatest amount of energy in the ecosystem is stored in the producers. There is more grass than grasshoppers, and there are more grasshoppers than frogs. There are very few tertiary consumers in an ecosystem because it takes a lot of energy to feed one. BIOMAGNIFICATION Toxins (poisons) can build up in the food chain. The toxin becomes more and more concentrated as you go up the trophic levels. Lesson 3: Evolution and Adaptations All organisms have adaptations that help them survive in their environment Examples of Plant Adaptations: Support/food storage: Stiff cell walls in stems and trunks, vascular tissue that carries water and food, Starch storage in roots. Prevention of water loss: Waxy cuticle, stomata on leaves, reduced leaf surface area (cactus), seed coats Reproduction: Seed dispersal by wind and animals, colors to attract pollinators, pollen, co-evolution with insects Defense: Toxins, thorns, bark Examples of Animal Adaptations: Protection and prevention of dehydration: exoskeletons, armor, scales, skin, kidneys Defense/Predation: Claws, teeth, well developed eye lens, sense of smell, speed, camouflage, armor, mimicry Reproduction: Eggs, internal fertilization, placentas, care of young, nesting Which one is venomous? Looks like owl eyes! This butterfly scares away potential predators Life is very Diverse Diversity is a measure of how many different types of organisms live in an area A rainforest is a very diverse habitat (many different species of plants, animals, fungi, etc.) A desert is not very diverse (Cacti and a few species of animals) A species is a group of animals that can breed and produce fertile offspring. (Cocker spaniel and poodle produce a cockapoo. Lion and tiger producing a liger. Elephant and a rabbit can not produced a rabbant!- not same species) Five basic components of 1. All species have genetic variation. Variation can be caused by mutations. Every species is different, even within itself. Look around you…are you all the same? 2. Organisms produce more offspring than can survive. The female green sea turtle lays a clutch of about 110 eggs. She may lay several clutches. It is likely that less than 1% of the hatchlings will ever reach sexual maturity. 3. Since more organisms are produced than can survive, there is competition (struggle for existence). Within and Among Species for food water shelter space And Within a Species for mates 4. The constant struggle for survival is affected by changes in the environment (hurricanes, earthquakes, floods, etc.) 5. SURVIVAL OF THE FITTEST Individuals that are best adapted to their environment survive and leave more offspring Over time, genes for favorable characteristics will be more common Example: giraffes and their increasingly longer necks Speciation If two populations of the same species become separated by a barrier, each group may change in different ways. Eventually they may become different enough that they are no longer the same species (can’t produce offspring together). Phylogenetic Trees are diagrams that show relationships C Present D E F G B 100mya A A is the common ancestor. B is extinct. E and F are the most closely related. Lesson 4: Viruses and Bacteria Viruses ARE NOT LIVING! Can only reproduce inside host cell Cell Specific- will only bind to certain cells Polio virus only attaches to human nerve cells Viruses destroy host cell! Viruses Viral infection must run their course- NO ANTIBIOTICS! There are vaccines that prevent some viral infections, like polio, influenza and chicken pox. An organism’s immune system fights viruses with fever & antibodies. Viral diseases HIV Destroys Helper T cells of the immune system Causes AIDS Influenza and common cold spread by contact Bacteria shapes A. B. C. Coccus: round or spherical Spirillum: spiral-shaped Bacillus: rod-shaped Coccus Bacillus Spirillum Bacteria Good Types Nitrogen-fixing bacteria (Nitrogen cycle) Bad Types Cause disease In food (Lactobacillus in yogurt) In digestive system (E. coli) Decomposers Strep throat Diphtheria Staph infection Food poisoning Bacterial infections can be treated with antibiotics