Microscope Parts and Functions

Microscope Parts & Functions

• Ocular Lens is the lens you look through
• Revolving Nosepiece holds two or more objective lenses and rotates to change power
• Mechanical Stage holds a slide in place and allows repositioning
• Stage securely holds and positions the sample being observed
• Substage Condenser focuses and concentrates light onto the specimen
• Diaphragm controls the amount and angle of light reaching the specimen
• Base provides foundational support
• X & Y Axis Knob allows for movement; the X-axis knob controls horizontal movement (left/right) of the specimen stage, the Y-axis knob controls vertical movement (up/down)
• Sliding Interpupillary Adjustment adjusts the distance between the two eyepieces
• Arm connects the base to the head (or body tube)
• Objective Lens gathers light from the specimen, magnifies the image, and projects it into the body tube for further magnification by the eyepiece lens
• Coarse focus knob makes large, quick adjustments to the focus
• Fine focus knob makes small, precise adjustments to the focus
• On+Off Switch controls power to the illuminator
• Light intensity control knob adjusts the brightness of the light illuminating the specimen

Animal Behavior

• Ethology is the study of animal behavior
• Action patterns are the smallest unit of behavior consisting of repeated, stereotyped, and clearly defined movements and postures
• Animal behavior is based on the ability to move, which relies on the muscular system
• Movements are responses to survival and reproduction needs
• Habitat refers to the location where an organism lives
• Niche is the functional role an organism plays in its environment, including its habitat, what it eats, how it interacts with other species, and nutrient cycling
• External stimulus refers to changes to conditions outside the body
• Phototaxis is a response to the stimulus of light
  • Positive phototaxis involves movement toward light
  • Negative phototaxis involves movement away from light
• Internal stimulus refers to changes to conditions inside the body

Photosynthesis & Respiration

• Nearly all organisms derive energy from sunlight either directly or indirectly
• The process traps solar energy and stores it as chemical energy in the bonds of a sugar molecule
• The formula is 6 carbon dioxide (6CO₂) + 6 water (6H₂O) + light energy → glucose (C₆H₁₂O₆) + 6 oxygen (6O₂)
• Photosynthesis occurs in chloroplasts, where pigments like chlorophyll capture sunlight
• The ultimate goal of photosynthesis is to produce glucose, storing energy, releases oxygen as a product
• Bacteria and protists, are large contributors to energy flow in ecosystems
• Carbs are used for energy
• All cells metabolize glucose for energy
• Usable energy is harvested (in the form of ATP) from sugar molecules, producing carbon dioxide and water
• This process takes place in the mitochondria and cytoplasm
• Glucose (C6H12O6) plus oxygen (6O2) yields carbon dioxide (6CO2) plus water (6H2O) plus energy (ATP)
• Aerobic respiration occurs in the presence of oxygen, producing about 38 ATP total
• Anaerobic respiration (fermentation) occurs without oxygen, producing about 2 ATP total so is usually a last resort

Ecology

• Ecology studies the interaction between living organisms and their physical environment
  • Abiotic factors are non-living factors, like climate, light, temperature, water availability, and nutrients
  • Biotic factors are living factors, like bacteria, fungi, protists, plants, and animals
• An ecosystem includes all organisms and their interactions with the nonliving environment within a defined area
• Habitat is the environment in which an organism or population lives
• Community includes all populations that interact with one another within a defined area
• Population is a group of organisms of the same species that occupy a particular area
• Nutrients are atoms and molecules that organisms obtain from their environment and are recycled by detritivores, saprophytes, and decomposers
  • Examples include oxygen, carbon, nitrogen, and hydrogen
• Energy is captured from producers (through photosynthesis or chemosynthesis) and then gained by consuming
• Nutrients are recycled but energy is not
• Decomposers break down dead or decaying bodies and waste
• Saprophytes secrete digestive enzymes outside their bodies to break down nearby organic material into simple compounds
  • Examples include fungi and bacteria
• Detritivores feed on detritus (debris)
  • Examples include nematodes, beetles, and millipedes
• Energy is passed through trophic levels (feeding levels)
• The 1st trophic level consists of producers/autotrophs that make their own food
• The 2nd trophic level consists of primary consumers/heterotrophs that acquire energy/nutrients from eating producers
• The 3rd trophic level and beyond consists of secondary (and tertiary) consumers that eat primary consumers
• Succession is a gradual change in a community and its nonliving environment where groups of species replace one another in a predictable sequence
• Succession starts with a disturbance
• Pioneers colonize an area until a climax community is reached
• Primary succession is the gradual formation of a community where no remnants of life exist, like after a volcanic eruption or nuclear explosion
• Secondary succession is when a new community develops after an existing ecosystem is damaged but remnants of life still exist, like after a forest fire or disease outbreak