Biology 101 Exam 3

Lesson 15

  • Explain how “emergent properties” arise from the structure and function of

individual components of a system

  •  Give examples of homeostasis in the body and the consequences of imbalance

    • Homeostasis: recreating equilibrium in the body by balancing out the effects of the outside system by having a well functioning internal system. Ex. Regulating body temperature.  

    • Consequences: bodily functions don’t perform accordingly, idk man insert something smart here

    • Negative feedback:  any control mechanism that reduces or reverses a change in internal environment. Ex. Regulation of glucose in bloodstream. 

    • Positive feedback: opposite, ex. Forming a blood clot to control bleeding.

  • Describe the basic components of the immune system

    • Pathogen: virus, bacteria or fungus; disease causing agent 

    • Innate Immunity: type of immunity present in animal before exposure to pathogens; effective from birth.  

      • External barriers of innate immune system: skin/exoskeleton, acidic environment, secretions, mucous membranes, cilia 

    • Inflammatory response:  Innate body defense in vertebrates which is caused by release of histamine and chemical alarm signals, trigger inc blood flow, inc wbc, fluid leakage from blood.

      •  Symptoms of redness, heat, and swelling in tissues.  

      • Histamine dilates blood vessels

      • Dilation inc amnt of wbc going to injured site

    • Adaptive immunity: acquired immunity, specific for each individual, comes through exposure to specific pathogens.  

    • Innate vs adaptive immunity: 

      •  Innate: rapid response, recognize broad ranges of pathogens, no memory. 

      • Adaptive: slower response, recognize specific pathogens, have memory.  

    • Antigen: Foreign molecule that elicits an adaptive immune response 

    • Antibody: immune protein found in blood plasma that attaches to a particular kind of antigen and helps counter its effects 

    • Lymphocytes: white blood cells responsible for adaptive immunity (part of active immunity)

      • B lymphocytes and T 

      • Each lymphocyte has a different antigen receptor

    • Active vs. passive immunity: 

      • Active: body receives antigens and makes its own antibodies

      • Passive: the body gets premade antibodies

    • Humoral immune response: produces antigen specific antibodies 

    • Cell-mediated immune response: doesn’t produce the antigen-specific antibodies 

      • Responds to threats inside host cell

    • Cytotoxic T-cell: binds to infected body cell, release perfonin which puts a hole in the infected cell, puts in enzymes to break down the infected cell’s proteins, and kills that cell. This prevents spread of infectious cells. 

      • Many cancers caused by viruses, this cell helps a lot

    • Antibodies are free floating B-cell antigen receptors

    • Antibodies bind to antigens


  • Memory B cells: recognize and kill the virus if it comes later

  • Effector cells: s recognize and kill the virus when it first comes in

  • Primary immune response: Initial adaptive immune response to antigen 

  • Secondary immune response:  Adaptive immune response when organism encounters a previously recognized antigen. 

  • Antibodies neutralize pathogens

    • Neutralization:  bind to surface proteins on virus/bacterium

    • Afterwards macrophages engulf pathogen

  • Herd immunity: when majority of population has antibodies for disease, those who don’t have antibodies will be protected

Lesson 16

  • Describe the structure and function of male and female anatomy.

    • Male Anatomy

      • Semen - 95% glandular secretions; 5% sperm

        • Has alkaline substances

          • Counteract acidity in urethra and vagina

        • Mucus necessary?

          • Helps sperm swim through vagina and cervix

        • (buy no, get 50% free)

        • Seminal vesicles - produce mucus and fructose

          • Fructose to give sperm ATP to support swimming 

        • Prostate - milky fluid with proteins

        • Bulbourethral - alkaline mucus

        • Frequent urination can occur due to prostate gland compressing bladder

        • Vasectomy performed by cutting vans deferens 

      • Path taken to exit: testis > epididymis > vans deferens > ejaculatory duct > urethra > out

    • Female anatomy 

      • Path taken to fertilize egg: cervix > uterus > oviduct 

        • (egg met at oviduct)

      • Eggs develop in follicles then go to oviduct

        • Egg grows in follicles in the ovary. Follicle ruptures and the egg goes to the fallopian tube.

      • Fertilized egg grows in uterus 

Lesson 17

  • Illustrate how the hormones and anatomy of the reproductive age female change over a month-- with and without pregnancy.

    • Spermatogenesis 

      • Go through mitosis and meiosis a bunch of times

      • Starts at puberty

      • Goes on continuously (I think)

    • Oogenesis 

      • Primary oocyte 

        • Born with all they will have

        • Arrested at prophase 1

        • Remains in ovary

        • Splits into first polar body and secondary oocyte

      • Secondary oocyte

        • Arrested at metaphase II (meiosis I complete)

        • Ruptures follicle 

        • Start developing at puberty

        • Released during ovulation

      • Egg cell

        • When secondary oocyte is fertilized, it is split into polar body and egg cell

      • How do twins work?

        • Fraternal twins: separate eggs fertilized by separate sperm

        • Single fertilized by single sperm, then splits the 2

    • Hormones in Female

  • Explain how the pill prevents pregnancy.

    • Pregnancy test -> detect Human Chorionic gonadotropin (HCG) which is secreted by embryo

    • To stimulate egg production > FSH and LH

    • Pill

      • Contains progesterone (needed) and estrogen (optional)

      • Why??? (check graphs above) (progesterone limits hypothalamus from releasing FSH and LH, which are needed for follicle growth)

Lesson 18

  • Determine if two organisms are from the same species; be able to explain the benefits and draw-backs of different definitions of a species

    • Biodiversity measured by

      • Number of 

    • Biological species concept - individuals of the same species can in interbreed and produce fertile offspring

      • Used in the book

      • Problem: the labradoodle is healthy and fertile, but is the result of a labrador and poodle mating

        • Many designer dogs the result of 1+ purebreds

    • Morphological species concept - individuals of the same species have shared physical traits

      • Used with fossils 

    • Ecological species concept - individuals of the same species play their own unique role in the community

    • Phylogenetic species concept - individuals of the same species share a common ancestor 

  • Explain the uses for the biological species concept of species and its limitations.

    • Problem 1: the labradoodle is healthy and fertile, but is the result of a labrador and poodle mating

      • Many designer dogs the result of 1+ purebreds

    • Problem 2: Can’t check if fossils can interbreed 

  • Explain the factors that determine the timing of life cycle events for a species.

    • Phenology - studying the timing of periodic cycle events such as when species do through development, migrations, mating, producing fruit, etc…

    • Factors that affect timing of lifecycle events

      • Photoperiod - period of time each day during which an organisms receives illumination (aka, day length)

        • Can regulate spring phenology by delaying early leaf-out and advancing late leaf-out caused by temperature variations 

      • Temperature 

        • acute (chilling requirement)

        • Aggregate (heat accumulation) 

        • As temperatures rise, cherry blossom trees bloom earlier

      • Visual cues - learning from parents

      • Chemical changes - hormones 

  • Local extinctions

    • 27% of all species now locally extinct

    • 36% so sparse extinction is imminent 

  • Migration

    • Food 

    • Reproduction

    • Avoid stressful weather

    • Example: caterpillars 

Lesson 19

  • Explain how scientists estimate population size

    • Population: a group of individuals of a single species that occupy the same general area. The individuals rely on the same resources, influenced by the same environmental factors, and are likely to interact + breed w/ one another.

    • Population ecology: study of how members of a population interact with their environment, focusing on factors that influence population density and growth

    • Population density: number of individuals of a species per unit area or volume 

    • Population dispersion: the way individuals are spread within their area.  

    • Dispersion patterns

      • Clumped: individuals are grouped in patches, is the most common in nature. results from an unequal distribution of resources in the environment like food. Sea stars may clump.

      • Uniform dispersion pattern: even distribution of individuals over an area. Can be as a result of territorial behavior.

      • Random dispersion pattern: individuals are spaced in an unpredictable way. It’s rare bc varying habitat conditions and social interactions. 

  • Use the exponential growth model to calculate population growth.

    • Number of individuals in population = (1 + r)^(number to time intervals/years) * initial number of individuals in population 

  • Compare and contrast logistic and exponential models of growth.

    • Logistic 

      • Don’t grow as fast

      • ‘Flatten off’ after some time

      • Include some kind of limitation to population growth (have a ‘K’)

    • Exponential 

      • Grow fast

      • No limits

      • Models human population currently

  • Explain the difference between density dependent and independent population change

    • Density dependent inhibition

      • Number of individuals (more specifically, density of individuals) matters

        • Ex. increased competition, predation…

    • Density independent inhibition

      • Number of individuals doesn’t matter

        • Ex. forest fire