BIOL 1202 Final Exam Study Guide: Animal Reproduction, Behavior, Ecology, Conservation, Evolution, Osmoregulation

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Animal Reproduction (Chapter 46)

Sexual vs. Asexual Reproduction

Reproduction is the biological process by which new individuals are produced. It can occur via sexual or asexual mechanisms, each with distinct advantages and disadvantages.

Sexual reproduction: Involves the fusion of haploid gametes (egg and sperm) to form a diploid zygote. This process generates genetic variation through recombination.
Asexual reproduction: Offspring are produced without gamete fusion. Types include fission, budding, fragmentation/regeneration, and parthenogenesis. Offspring are genetically similar to the parent.
Advantages of sexual reproduction: Increased genetic variation, adaptability to changing environments, and improved resistance to disease.
Advantages of asexual reproduction: Rapid reproduction, no need for a mate, and every individual can reproduce.
Example: Parthenogenesis in lizards—offspring develop from unfertilized eggs and are genetically identical to the mother.

Reproductive Strategies and Variations

Hermaphroditism: Individuals possess both male and female reproductive organs (e.g., earthworms).
Fertilization: External (requires water, many gametes) vs. Internal (greater protection, higher energy cost).
Oviparity: Eggs laid outside the body.
Ovoviviparity: Eggs retained inside until hatching.
Viviparity: Embryo develops inside mother, receives direct nourishment.

Male Mammalian Reproduction

Testes: Contain seminiferous tubules for sperm production.
Leydig cells: Produce testosterone.
Sperm pathway: Seminiferous tubules → epididymis → vas deferens → ejaculatory duct → urethra.
Accessory glands: Prostate (enzymes/nutrients), bulbourethral glands (mucus, neutralizes acidity).
Spermatogenesis: Continuous and prolific.
Steroid abuse: Can reduce FSH/LH, lower testosterone, cause sterility.

Female Mammalian Reproduction

Oogenesis: Unequal cytokinesis produces one ovum and polar bodies; begins before birth and includes pauses.
Cycles: Uterine (menstrual) cycle tracks uterine changes; ovarian cycle tracks follicle development and ovulation.
Hormonal regulation: GnRH stimulates FSH/LH; FSH/LH stimulate follicle development; follicles produce estrogen.
Ovulation: High estrogen triggers LH surge (positive feedback).
Progesterone: From corpus luteum, maintains uterine lining, inhibits GnRH (negative feedback).
Cycle reset: If no pregnancy, corpus luteum degenerates, estrogen/progesterone drop.

Fertilization, Pregnancy, and Contraception

hCG: Maintains corpus luteum early in pregnancy.
Placental mammals: Embryo develops in uterus.
Hormonal contraception: Suppresses GnRH/FSH/LH to prevent ovulation.
Other methods: IUDs, condoms, diaphragms, abstinence.

Animal Behavior (Chapter 51)

Proximate vs. Ultimate Causes

Animal behavior is a coordinated response to environmental or internal stimuli. Understanding behavior involves distinguishing between proximate (how) and ultimate (why) causes.

Proximate causes: Mechanisms such as stimuli, hormones, nerves, muscles, and development.
Ultimate causes: Fitness advantage, survival, reproduction, and natural selection.
Tinbergen’s four questions: Mechanism, development, function, evolutionary history.
Example: Cicada singing—proximate: daylight/hormones; ultimate: mate attraction.

Innate Behavior

Innate behaviors: Genetically programmed, appear without learning.
Fixed action pattern (FAP): Unlearned sequence triggered by a sign stimulus, carried to completion (e.g., goose rolling egg).
Honeybee dance language: Round dance (nearby food), waggle dance (farther food, direction).
Stimulus-response chains: One behavior triggers the next (e.g., fruit fly courtship).

Learning

Imprinting: Long-lasting behavior learned during a sensitive period.
Spatial learning: Remembering locations or spatial relationships.
Classical conditioning: Linking one stimulus with another (e.g., Pavlov’s dogs).
Operant conditioning: Behavior associated with reward or punishment.
Cognition/problem solving: Mental processing to overcome obstacles.
Social learning: Learning by observing others.
Note: Most behaviors include both innate and learned components.

Adaptive Value of Behavior

Optimal foraging: Maximizes energy gained relative to time/risk spent.
Inclusive fitness/Hamilton’s rule: Helping relatives can spread genes.
Reciprocal altruism: Helping with expectation of return help.
Game theory: Behavior depends on what others do.

Population Ecology (Chapter 53)

Population Structure and Growth

Population ecology studies the size, density, dispersion, and dynamics of populations.

Population: Individuals of the same species in the same area.
Density: Number per area.
Dispersion: Clumped, uniform, random patterns.
Demographics: Birth/death rates, age structure.
Example: Clumped dispersion—individuals in groups; random—no grouping.

Estimating Population Size

Methods: Sample plots/quadrats, indirect indicators, capture-mark-recapture (CMR).
CMR assumptions: Equal catch probability, remixing, no population change during study.

Demography and Growth Models

Life tables: Age-specific survival and reproduction.
Survivorship curves: Type I (high survival until late), Type II (constant death rate), Type III (many die young).
Exponential growth: Unlimited resources, J-shaped curve.
Logistic growth: Includes carrying capacity (K), S-shaped curve.

Exponential growth equation:

Logistic growth equation:

Density Effects and Life History

Density-dependent factors: Disease, competition, territoriality.
Density-independent factors: Hurricanes, freezes, droughts.
Semelparity: One big reproductive event.
Iteroparity: Repeated reproductive events.
Metapopulation: Population of populations connected by dispersal.

Community Ecology (Chapter 54)

Community Interactions

Community ecology examines interactions among species and their effects on diversity and structure.

Community: Populations of different species living together.
Interspecific interactions: Competition (-/-), predation (+/-), herbivory (+/-), parasitism (+/-), mutualism (+/+), commensalism (+/0).

Competition and Niches

Competitive exclusion principle: Two species using the same limiting resource cannot coexist indefinitely.
Niche: Abiotic and biotic resources used by a species; its role in the community.
Fundamental niche: Where a species could live without competition.
Realized niche: Where it actually lives with competition.
Resource partitioning: Coexistence by specializing in time, space, or resource type.
Character displacement: Trait differences become more pronounced where competing species coexist.

Predation, Warning Signals, and Mimicry

Crypsis: Camouflage to avoid detection.
Aposematic coloration: Warning coloration indicating danger or bad taste.
Batesian mimicry: Harmless species mimics harmful one.
Müllerian mimicry: Two harmful species resemble each other.

Diversity, Food Webs, and Species Effects

Species diversity: Richness and relative abundance.
Food webs: Show trophic structure; food chain length limited by energy transfer.
Dominant species: Most abundant/high biomass.
Keystone species: Disproportionately large effect relative to abundance.
Ecosystem engineers: Physically modify habitats (e.g., beavers).

Disturbance and Biogeography

Intermediate disturbance hypothesis: Moderate disturbance maintains higher diversity.
Island biogeography: More species on larger/closer islands.
Tropical diversity: Lower latitudes support greater diversity.

Conservation Biology (Chapter 56)

Biodiversity and Its Importance

Conservation biology aims to prevent biodiversity loss and maintain ecosystem services.

Biodiversity levels: Genetic, species, ecosystem/community diversity.
Current crisis: Sixth mass extinction.
Natural resources: Food, medicine, timber, fisheries.
Ecosystem services: Pollination, nutrient cycling, water purification, climate regulation.
Ethics/aesthetics: Species have intrinsic value.

Main Threats and Conservation Strategies

Major threats: Habitat loss, invasive species, overexploitation, climate change, pollution.
Extinction vortex: Small populations decline due to genetic problems/random events.
Critical habitat: Essential for species survival/recovery.
Conservation biology: Documents biodiversity, investigates human impacts, develops solutions.

Evolution

Mechanisms and Evidence

Evolution is the change in allele frequencies in a population over time, driven by mechanisms such as natural selection and genetic drift.

Darwin’s contribution: Natural selection as the mechanism for adaptive evolution.
Genetic drift: Random change in allele frequencies, strongest in small populations.
Evidence: Fossils, homology, direct observation, biogeography, genetics.
Homology: Similarity due to shared ancestry.
Analogy: Similarity due to convergent evolution/shared function.
Phylogenies: Hypothesized evolutionary relationships based on common ancestry.

Types of Natural Selection and Speciation

Types of selection: Directional, stabilizing, disruptive.
Speciation: Allopatric (geographic isolation) or sympatric (same area); reproductive isolation can be prezygotic or postzygotic.

Hardy-Weinberg Equilibrium

Null model: Allele frequencies do not change in the absence of evolutionary forces.

Hardy-Weinberg equation:

Osmoregulation and Excretion (Chapter 44)

Homeostasis and Osmoregulation

Osmoregulation maintains water and ion balance, pH, oxygen, energy, temperature, and nitrogen waste control.

Hyperosmotic: Water moves out.
Hypoosmotic: Water moves in.
Isosmotic: Equal solute concentration.
Osmoconformers: Match external osmolarity, save energy.
Osmoregulators: Actively control internal osmolarity.

Nitrogenous Waste and Excretory Systems

Ammonia: Cheap, toxic, water-demanding.
Urea: Intermediate toxicity and water use.
Uric acid: Saves water, high energy cost.
Excretory functions: Filtration, reabsorption, secretion, excretion.
Systems: Flatworms (protonephridia), earthworms (metanephridia), insects (Malpighian tubules), mammals (kidneys).

Nephron Structure and Function

Parts: Renal corpuscle, proximal tubule, loop of Henle, distal tubule, collecting duct.
Juxtamedullary nephrons: Long loops, conserve water.
Descending limb: Loses water.
Ascending limb: Moves salt out, creates medullary osmotic gradient.
ADH: Increases water reabsorption.
Aldosterone: Increases NaCl reabsorption.

Ecology & Biosphere (Chapter 52)

Ecology and Climate

Ecology studies the distribution, abundance, and interactions of organisms. Climate is the long-term prevailing weather conditions, shaped by temperature, precipitation, sunlight, and wind.

Main drivers: Solar radiation, atmospheric circulation, ocean currents, seasonality, rain-shadow effects.
Biomes: Broad ecological patterns predicted by temperature and precipitation.
Aquatic systems: Influenced by light and nutrient availability.

Absolute Must-Know List

Parthenogenesis: Development of offspring from an unfertilized egg.
Proximate vs. ultimate: Proximate = how; ultimate = why.
FAP: Unlearned sequence triggered by a simple cue, carried to completion.
Exponential vs. logistic growth: Exponential = unlimited resources; logistic = carrying capacity limits growth.
Dispersion: Clumped, random, uniform.
Interaction types: Competition = -/- ; mutualism = +/+ ; commensalism = +/0 ; predation/parasitism/herbivory = +/-
Niche: Fundamental vs. realized.
Keystone species: Large effect, not necessarily most abundant.
Biodiversity: Genetic + species + ecosystem/community diversity.
Main conservation threats: Habitat loss, invasive species, overexploitation, climate change, pollution.
Osmoregulation: Hyper = water out; hypo = water in.
Hormones: ADH = keep water; aldosterone = keep sodium.
Homology vs. analogy: Homology = shared ancestry; analogy = shared function.

Interaction Type	Effect on Species 1	Effect on Species 2
Competition	-	-
Mutualism	+	+
Commensalism	+	0
Predation/Parasitism/Herbivory	+	-

Growth Model	Equation	Curve Shape
Exponential		J-shaped
Logistic		S-shaped

Dispersion Pattern	Description
Clumped	Individuals grouped together
Uniform	Even spacing
Random	No predictable pattern