Chapters 1, 2 & 9 The quick & dirty version
What is Biology? • Biology – the study of life • Involves many aspects: ecology, cellular biology, biochemistry, molecular biology, genetics, evolution, zoology, botany, etc.
Characteristics of Living Things • Have an orderly structure • Produce offspring • Grow and develop • Adjust to changes in the environment
Organization • Cell or cells that function together • DNA or RNA that provides information to control life’s processes
Reproduction • The production of offspring is not essential to an individual organism, but for the continuation of a species • Can be sexual or asexual Picture Censored
Change • Living things change during their lives • Growth results in an increase in the amount of living material and the formation of new structures • Development is all of the changes that take place during the life of an organism
Adjust to Environment • Environment – an organism’s surroundings, including air, water, weather, temperature, and many other factors • Stimulus – anything in an organism’s external or internal environment that causes the organism to react • Response – reaction to a stimulus
Adjust to environment • Homeostasis – regulation of an organism’s internal environment to maintain conditions suitable for survival • Done by using energy
Adapt and Evolve • Adaptation – any structure, behavior, or internal process that enables an organism to respond to environmental factors and live to produce offspring • Inherited from previous generations • “Survival of the fittest” • Evolution – the gradual change in a species through adaptations over time
Review • What is biology? • What are the 4 characteristics of living things? • How are living things organized? • Which characteristic of living things is essential to a species, but not to an individual? • Give an example of a stimulus and response in nature? • What is homeostasis? • What is an adaptation?
What is Ecology? • Ecology – the scientific study of interactions among organisms and their environments. • Reveals relationships among living and nonliving parts of the world
Aspects of Ecological Study • Biosphere – the portion of Earth that supports life • Extends from bottom of ocean to high in the atmosphere • If the Earth were an apple, the biosphere would be thinner than the peel • Abiotic Factors – the nonliving parts of an organism’s environment • Light, minerals, temperature, air composition, soil, rocks, etc. • Biotic Factors – the living organisms that inhabit an environment • 6 Kingdoms: • Animalae, Plantae, Fungi, Protista, Eubacteria, Archaebacteria
Levels of Organization in Ecology • Organism - anything that possesses all the characteristics of life • Population – a group of organisms of one species that interbreed and live in the same place at the same time • Ex: All the bass in Utah Lake, the elk near Hardware Ranch • They may compete for resources, mates, etc. if there are limitations • Community – a collection of interacting populations • Ex: everything alive in Utah Lake or near Hardware Ranch • Communities may also compete for resources, or may even be dependent on each other for food, needed gasses, etc.
Levels of Organization in Ecology • Ecosystem – made up of the interactions among the populations in a community and the community’s physical surroundings, or abiotic factors • Three Kinds: terrestrial, freshwater aquatic, saltwater aquatic (marine) • There are all kinds of interactions in an ecosystem • Biome • Biosphere Coral Reefs are a rich, diverse and productive ecosystems A coastal wetland on Lake Superior, Wisconsin. Photo by K. Rodriquez
Organisms in Ecosystems • Habitat – the place where an organism lives out its life • Ex: prairie dog in a grassland, birds in a beech-maple forest • Habitats change and even disappear • Niche – the role and position a species has in its environment – how it meets its needs for food and shelter, how it survives, and how it reproduces • Ex: under a rotting log • A worm gets nutrients from organic material in soil • A centipede captures and eats beetles and other animals • Ants eat dead insects • A millipede eats decaying leaves near the log • No two species can occupy the same niche • If they try, competition results
Living Relationships • Predator – Prey relationships • Are inversely related • Symbiosis (means living together) – the relationship in which there is a close and permanent association among organisms of different species
Kinds of Symbioses • Commensalism – one species benefits and the other is neither harmed nor benefited • Ex: bacteria on your face, Spanish moss on branches of trees • Mutualism – both species benefit • Ex: flowers and bees, bacteria and plants • Parasitism – one organism derives benefit at the expense of the other • Ex: ticks and animals, tapeworms and animals
Review • What is ecology? • What is the biosphere? • Give 3 abiotic and 3 biotic factors in this room. • What is the difference between a population and a community? • What is the difference between a habitat and a niche? • What is a predator-prey relationship? Give an example. • Give one type of symbiosis and give an example.
How Organisms Obtain Energy • All energy originates from the sun • Autotrophs – organisms that use the energy from the sun (photoautotrophs) • or energy stored in chemical compounds (chemoautotrophs) to manufacture their own nutrients
Heterotrophs • Organisms that cannot make their own food and must feed on other organisms • Herbivores – feed on autotrophs • Carnivores – eat other heterotrophs • Omnivores – feed on both autotrophs and other heterotrophs • Scavengers – eat animals that have already died • Decomposers – break down and absorb nutrients from dead organisms
Food Chains • Matter & energy flow through organisms in ecosystems (law of conservation of energy) • Food Chain – a simple model that shows how matter and energy move through an ecosystem (what eats what) • Give me an example • There is less energy at each successive step of the food chain
Food Web • Expresses all the possible feeding relationships at each trophic level in a community • More realistic than a food chain because organisms depend on more than one other species for food • As you draw a food web, the arrows represent the direction of energy flow Pg. 51 of book
Trophic Levels • Each organism in a food chain represents a feeding step, or a trophic level, in the passage of energy and materials • 1st trophic level – autotrophs • 2nd trophic level - 1° heterotrophs • Herbivores, omnivores, decomposers, scavengers • 3rd trophic level - 2° heterotrophs • Omnivores, carnivores, decomposers, scavengers • 4th trophic level - 3° heterotrophs • Omnivores, carnivores, decomposers, scavengers
Ecological Pyramid • Shows how energy flows through an ecosystem • 10% Rule: only about 10% of all energy can be passed from one trophic level to the next 3° Consumer (1 Joule) 2° Consumer (11 Joules) 1° Consumer (98 Joules) Producers (1025 Joules) Pyramid of Energy Pg. 52
Review • What is the difference between a photoautotroph and a chemoautotroph? • What are the 5 types of heterotrophs? • Give an example of a food chain with at least 4 organisms. • What is the difference between a food chain and a food web? • What is a trophic level? • What is the 10% rule? • What shape are ecological pyramids?
ATP - Life’s Energy • Adenosine triphosphate • ATP stores energy in the bonds between adenosine and three phosphates (which are charged). • When a bond between phosphates is broken, energy is released • Stored by creating bond
Photosynthesis • The process that uses the sun’s energy to make simple sugars • These sugars are then converted into complex carbohydrates • There are two phases to photosynthesis: • The light-dependent reactions (convert light energy into chemical energy, ATP) • The light-independent reactions (produce simple sugars) • 6CO2 + 6H20 C6H12O6 + 6O2
The Chloroplast & Pigments • Membranes in chloroplast contain pigments – molecules that absorb specific wavelengths of sunlight • Chlorophyll is the most common pigment • Absorbs most wavelengths of light except green
Light-Dependent Reactions • Light excites (energizes) electrons in the membranes • This energy is used to form ATP from ADP (adenosine diphosphate), which will be used in the light independent reactions • Electrons then combine with some “stuff” to make something called NADPH, which will also be used in the light independent reactions
Why is Water Needed? • Chloroplasts constantly need new electrons • Plants split water to get molecules in a process known as photolysis (2 electrons per water molecule) • Oxygen is released into the air through little holes in leaves called stomata (who uses it?)
Light-Independent Reactions • The Calvin cycle (Melvin Calvin) is a series of reactions that use carbon dioxide to form sugars • Uses what was produced in light rxns & CO2 from atmosphere (comes in through stomata)
Section Review • Why do you see green when you look at a leaf? • Why do you see other colors in the fall? • How do the light-dependent reactions of photosynthesis relate to the Calvin Cycle? • What is the function of water in photosynthesis? • Is chlorophyll a reactant, product, or neither in photosynthesis?
Cellular Respiration • The process by which mitochondria break down food molecules to produce ATP. • Three stages: • Glycolysis • Citric acid cycle (Krebs cycle) • Electron transport chain • Glycolysis is anaerobic (no oxygen required) • The other two stages are aerobic
Glycolysis • Glycolysis is a series of chemical reactions in the cytoplasm of a cell that break down glucose in two • 2 ATP are required • 4 ATP are made • 2 NADH are made
Citric Acid Cycle • Also called the Krebs cycle • A series of chemical reactions similar to the Calvin cycle • Products per turn of cycle (2 turns per glucose) • 3 NADH • 2 CO2 - then breathed out • 1 FADH2 • 1 ATP - Usable energy
ATP Totals from Aerobic Respiration • 10 NADH molecules = 30 ATP • Each NADH leads to 3 ATP • 2 FADH2 molecules = 4 ATP • Each FADH2 leads to 2 ATP • 2 ATP during glycolysis • 4 ATP are made, but 2 are used • 2 ATP during citric acid cycle • 1 per pyruvic acid • GRAND TOTAL = 38 ATP per glucose Ms. Lowe’s Video
Fermentation • Anaerobic process • Follows glycolysis and provides a means to continue producing ATP until oxygen is available again • 2 major types: • Lactic acid fermentation (lactic acid produced - in animals, for instance) • Alcoholic fermentation (ethanol & carbon dioxide produced - yeast)
Photosynthesis Cellular Respiration Food synthesized Food broken down Energy from sun stored in glucose Energy of glucose released O2 given off O2 taken in Produces sugars from PGAL Produces CO2 and H2O Requires light Doesn’t require light Occurs only in the presence of chlorophyll Occurs in ALL living cells Comparing Photosynthesis and Cellular Respiration
Section Review • How much ATP is made in glycolysis? In aerobic respiration? In anaerobic? • How do alcoholic fermentation and lactic acid fermentation differ? • How is most of the ATP from aerobic respiration produced? • Why is lactic acid fermentation important to the cell when oxygen is scarce? • Who will build up more lactic acid, a jogger or a sprinter?