Ninth Grade Biology
Study Guide for Final Exam
Chapter 11 (Sections 1, 2, 3, 5,6): The Evolution of Populations
Vocabulary: gene pool, allele frequency, microevolution, natural selection, gene flow,
genetic drift, sexual selection, speciation, reproductive isolation, geographic isolation,
convergent evolution, divergent evolution, extinction, coevolution.
Section 11.1: Genetic Variation Within Populations
Key concept: A population shares a common gene pool.
Main ideas: Genetic variation in a population increases the chance that some individuals
will survive.
Genetic variation comes from several sources (e.g. mutations, and recombination).
Section 11.2: Natural Selection in Populations
Key concept: Populations, not individuals, evolve.
Main ideas: Natural Selection acts on distribution of traits.
Natural selection can change the distribution of a trait in one of three ways.
Section 11.3: Other Mechanisms of Evolution
Key concept: Natural Selection is not the only mechanism through which populations
evolve.
Main ideas: Gene flow is the movement of alleles between populations.
Genetic drift is a change in allele frequencies due to chance.
Sexual selection occurs when certain traits increase mating success.
Section 11.5: Speciation Through Isolation
Key concept: New species can arise when populations are isolated.
Main ideas: The isolation of populations can lead to speciation.
Populations can become isolated in several ways.
Section 11.6 Patterns in Evolution
Key concept: Evolution occurs in patterns.
Main ideas: Evolution through natural selection is not random.
Species can shape each other over time. Species can become extinct.
Chapter 13 (Sections 1, 2, 3, 4, 5, 6): Principles of Ecology
Vocabulary: ecology, community, ecosystem, organism, population, biome, biotic,
abiotic, biodiversity, producer, consumer, food chain, herbivore, carnivore, omnivore,
decomposer, food web, trophic level, hydrologic cycle, nitrogen fixation, biogeochemical
cycle, energy pyramid.
Section 13.1: Ecologists Study Relationships
Key concept: ecology is the study of the relationships among organisms and their
environment.
Main ideas: Ecologists study environments at different levels of organization: organism,
population, community, ecosystem, biome.
Section 13.2: Biotic and Abiotic Factors
Key concept: Every ecosystem includes both living and nonliving factors.
Main ideas: An ecosystem includes both biotic (living) and abiotic (nonliving) factors.
Changing once factor in an ecosystem can affect many other factors.
Section 13.3: Energy in ecosystems
Key concept: Life in an ecosystem requires a source of energy.
Main ideas: Producers provide energy for other organisms in an ecosystem.
Almost all producers obtain energy from sunlight.
Section 13.4: Food chains and Food webs
Key concept: Food chains and food webs model the flow of energy in an ecosystem.
Main ideas: A food chain is a model that shows a sequence of feeding relationships.
A food web shows a complex network of feeding relationships.
Section 13.5: Cycling of Matter
Key concept: Matter cycles in and out of an ecosystem.
Main ideas: Water cycles through the environment.
Elements that are essential for life also cycle through ecosystems.
Section 13.6 Pyramid Models
Key concept: Pyramids model the distribution of energy and matter in an ecosystem.
Main ideas: An energy pyramid shows the distribution of energy among the trophic
levels.
Other pyramid models illustrate an ecosystem’s biomass and distribution of organisms.
Chapter 14 (Sections 1,2, 4,5): Interactions in Ecosystems
Vocabulary: habitat, ecological niche, competition, predation, symbiosis, mutualism,
commensalism, parasitism, immigration, emigration, carrying capacity, limiting factor,
exponential growth, logistic growth, succession, primary succession, secondary
succession.
Section 14.1: habitat and niche
Key concept: Every organism has a habitat and a niche.
Main ideas: A habitat differs from a niche.
Section 14.2: Community Interactions
Key concept: Organisms interact as individuals and as populations.
Main ideas: Competition and predation are two important ways in which organisms
interact.
Symbiosis is a close relationship between species.
Section 14.4: Population Growth Patterns
Key concept: Populations grow in predictable patterns.
Main ideas: Changes in a population’s size are determined by immigration, births,
emigration, and deaths.
Population growth is based on available resources.
Ecological factors limit population growth.
Section 14.5: Ecological Succession
Key concept: Ecological Succession is a process of change in the species that make up a
community.
Main ideas: Succession occurs following a disturbance in an ecosystem.
Chapter 16 (Sections 1,2): Human Impact on Ecosystems
Vocabulary: renewable resource, nonrenewable resource, pollution, smog, greenhouse
effect, global warming.
Section 16.1: Human population growth and natural resources.
Key concept: As the human population grows, the demand for Earth’s resources
increases.
Main ideas: Earth’s human population continues to grow.
The growing human population exerts pressure on Earth’s natural resources.
Section 16.2: Air Quality
Key concept: Fossil fuel emissions affect the biosphere.
Main ideas: Pollutants accumulate in the air.
Air pollution is changing Earth’s biosphere.
Chapter 29(Sections 1,2, 6): How Organ Systems Communicate
Vocabulary: nervous system, endocrine system, central nervous system, peripheral
nervous system, neuron, dendrite, axon, synapse, action potential, neurotransmitter,
hormone, gland.
Section 29.1: How Organ Systems Communicate
Key concept: The nervous system and the endocrine system provide the means by which
organ systems communicate.
Main ideas: The body’s communication systems help maintain homeostasis.
The nervous and endocrine systems have different methods and rates of communication.
Section 29.2: Neurons
Key concept: The nervous system is composed of highly specialized cells.
Main ideas: Neurons are highly specialized cells.
Neurons receive and transmit signals.
Section 29.6 The Endocrine System and Hormones
Key concept: The Endocrine System produces hormones that affect growth,
development, and homeostasis.
Main ideas: Hormones influence a cell’s activities by entering the cell or binding to its
membrane.
Endocrine glands secrete hormones that act throughout the body.
Chapter 30 (Sections 1, 2,3,4)
Vocabulary: circulatory system, respiratory system, lung, alveoli, heart, artery, vein,
capillary, red blood cell, atrium, ventricle, blood pressure.
Section 30.1: Respiratory and Circulatory Functions
Key concept: The respiratory and circulatory systems bring oxygen and nutrients to the
cells.
Main ideas: The respiratory and circulatory systems work together to maintain
homeostasis.
The respiratory system moves gases into and out of the blood.
The circulatory system moves blood to all parts of the body.
Section 30.2: respiration and gas exchange
Key concept: The respiratory system exchanges oxygen and carbon dioxide.
Main ideas: Gas exchange occurs in the alveoli of the lungs.
Section 30.3: The heart and circulation
Key concept: The heart is a muscular pump that moves the blood through two pathways.
Main ideas: The tissues and structures of the heart make it an efficient pump.
The heart pumps blood through two main pathways.
Section 30.4: Blood Vessels and Transport
Key concept: The circulatory system transports materials throughout the body.
Main ideas: Arteries, veins, and capillaries transport blood to all parts of the body.
Lifestyle plays a key role in circulatory diseases.
Chapter 31 ( 1,2,3,6): Immune System and Disease
Vocabulary: pathogen, immune system, T cell, B cell, antibody, cellular immunity,
humoral immunity, antigen, memory cell, leukemia, human immunodeficiency virus
(HIV), acquired immunodeficiency syndrome (AIDS).
Section 31.1: pathogens and human illness
Key concept: Germs cause many diseases in humans.
Main ideas: There are different types of pathogens.
Pathogens can enter the body in different ways.
Section 31.2: Immune System
Key concept: The immune system consists of organs, cells, and molecules that fight
infections.
Main ideas: Many body systems protect you from pathogens.
Cells and proteins fight the body’s infections.
Immunity prevents a person from getting sick from a pathogen.
Section 31.3: Immune Responses
Key concept: The immune system has many responses to pathogens and foreign cells.
Main ideas: Many body systems work to produce nonspecific responses.
Cells of the immune system produce specific responses.
The immune system rejects foreign tissues.
Section 31.6: Diseases That Weaken the Immune System
Key concept: When the immune system is weakened, the body cannot fight off diseases.
Main ideas: Leukemia is characterized by abnormal white blood cells.
HIV targets the immune system.