Big Idea 4 Ap Biology Essays

Transcript of AP Biology Big Idea #4

4A: Interactions within biological systems lead to complex properties.

4B: Competition and cooperation are important aspects of biological systems.

4C: Naturally occurring diversity among and between components within biological systems affects interactions with the environment. Interactions within biological
systems lead to complex properties. Naturally occurring diversity among and between components within biological systems affects interactions with the environment Competition and cooperation are important aspects of biological systems.
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for the Bio AP! Big Idea 4: SYSTEMS AND INTERACTIONS Biological systems interact,
and these systems and their interactions
possess complex properties. The structure and function of subcellular components,
and their interactions, provide essential cellular processes. Interactions between external stimuli and
regulated gene expression result in
specialization of cells, tissues Differentiation in development is due to external and internal cues that trigger gene regulation by proteins that bind to DNA.
Structural and functional divergence of cells in development is due to expression of genes specific to a particular tissue or organ type.
Environmental stimuli can affect gene expression in a mature cell. Organisms exhibit complex properties due to
interactions between their constituent parts. Interactions and coordination between organs provide essential biological activities.
ex. stomach and small intestines (digestion then absorption)
Interactions and coordination between systems provide essential biological activities
ex. nervous and muscular systems
Communities are composed of populations of
organisms that interact in complex ways. structure of a community is described in terms of species composition and species diversity
computer modeling used to study population relations and environmental impacts on communities
ex. global climate change computer modeling, also predicted predator-prey relations
mathematical modeling used for describing growth of populations
Reproduction without constraints results in the exponential growth of a population.
A population can produce a density of individuals that exceeds the system’s resource availability
As limits to growth due to density-dependent and density-independent factors are imposed, a logistic growth model generally ensues.
Demographics data with respect to age distributions and fecundity can be used to study human populations. Interactions among living
systems and with their environment
result in the movement of matter and energy. Energy flows, but matter is recycled
Primary productivity affected by global and regional climate as well as atmospheric conditions
interactions between organisms within a food web/chain
food webs/chains dependent on primary productivity
modeling allows researchers to predict changes
Logistic model :Competition for resources and other factors limiting growth
Density dependent regulation: Competition for resources, territoriality, health, predation, accumulation of wastes and other factors
Human activities impact ecosystems on local, regional and global scales.
more humans= larger impact on environment (environmental degradation)
destruction of habitat, decrease in population size, extinction all results
Organisms have specific adaptations for obtaining and utilizing energy in specific environments The subcomponents of biological molecules and their sequence determine the properties of that molecule. Structure and function of polymers is based on assembly of monomers
Nucleic Acids: each made of 5 C sugar, phosphate group, and nitrogenous base- structural differences between DNA and RNA account for their different functions
Proteins: primary structure-a.a. chain interacts with the environment to determine the overall shape of the protein- chemical properties of R group help determine tertiary structure
Lipids: usually non-polar molecules except for phospholipids which are amphipathic
Carbohydrates: sugar monomers whose structures and bonding with each other by dehydration synthesis determine the properties and functions of the molecules

Directionality influences structure and function of the polymer.
Nucleic acids: 3' and 5' carbons of the sugar in the nucleotide- synthesis of polymer ALWAYS occurs by adding to the 3' end of the molecule
Proteins have an amino (NH2) end and a carboxyl (COOH) end, and consist of a linear sequence of amino acids connected by the formation of peptide bonds by dehydration synthesis
carbohydrates: orientation of subunits determines their relative orientation in the carbohydrate, which then determines the secondary structure of the carbohydrate Ribosomes: site of protein synthesis composed of rRNA and proteins
Endoplasmic Reticulum: smooth=synthesis of lipids, rough=role in protein synthesis and packaging
The Golgi complex: series o flattened membrane sacs (cisternae), packages molecules in vesicles and creates lysosomes
Mitochondria: energy capture and transformation occur b/c of double membrane structure (cristae)
Lysosomes: intracellular digestion, important for apoptosis- vesicle containing hydrolytic enzymes
Vacuole: intracellular storage, in plants central vacuole holds water- membrane bound
Chloroplasts: capture light energy because they contain the green pigment chlorophyll and fix carbon into glucose- double membrane structure involves thylakoids (where light reactions happen) and stroma (where carbon fixation occurs)
Cooperative interactions within organisms promote efficiency in the use of energy and matter. Organisms have areas or compartments that perform a subset of functions related to energy and matter, and these parts contribute to the whole
At the cellular level, the plasma membrane, cytoplasm and, for eukaryotes, the organelles contribute to the overall specialization and functioning of the cell.
Within multicellular organisms, specialization of organs contributes to the overall functioning of the organism
Interactions among cells of a population of unicellular organisms can be similar to those of multicellular organisms, and these interactions lead to increased efficiency and utilization of energy and matter
Bacterial community in the rumen of animals Interactions between and within populations influence patterns of species distribution and abundance interactions between populations impact distribution and abundance
Competition, parasitism, predation, mutualism and commensalism can affect population dynamics.
Relationships among interacting populations can be characterized by positive and negative effects, and can be modeled mathematically (predator/prey, epidemiological models, invasive species).
Many complex symbiotic relationships exist in an ecosystem, and feedback control systems play a role in the functioning of these ecosystems
The cooperation and competition between individuals gives a population unique properties
Species-specific and environmental catastrophes, geological events, the sudden influx/depletion of abiotic resources or increased human activities affect species distribution and abundance.
ex. keystone species removal: Sea Otters off the California coast (linked to formation of urchin barrens)
Distribution of local and global ecosystems
changes over time Human impacts accelerate change at both local and global levels
human caused global climate change threaten ecosystems and life on Earth.
An introduced species can exploit a new niche free of predators or competitors
Introduction of new diseases can devastate native species like small pox with unexposed pop.
Geological and meteorological events impact ecosystem distribution
Meteor impact on dinosaur extinction
El Nino
Interactions between molecules affect their
structure and function Change in structure of molecule could change function
Shape of enzymes and active sites essential for proper enzyme function
Substrate(s) must fit into active site
Cofactors and coenzymes affect enzyme function; this interaction relates to a structural change that alters the activity rate of the enzyme. The enzyme may only become active when all the appropriate cofactors or coenzymes are present and bind to the appropriate sites on the enzyme.
Other factors affect enzyme activity either enhancing or inhibiting: Molecules can bind reversibly or irreversibly to the active or allosteric sites
The change in function of an enzyme can be interpreted from data regarding the concentrations of product or substrate as a function of time. These representations demonstrate the relationship between an enzyme’s activity, the disappearance of substrate, and/or presence of a competitive inhibitor.
Environmental factors influence the expression of the genotype in an organism Environmental factors influence traits directly and indirectly
Effect of increased UV on melanin production in animals (tanning)
An organism’s adaptation to the local environment reflects a flexible response of its genome
Alterations in timing of flowering due to climate change
The level of variation in a population affects population dynamics Population ability to respond to changes in the environment is affected by genetic diversity. Species and populations with little genetic diversity are at risk for extinction.
Prairie Chickens ex.
Genetic diversity allows individuals in a population to respond differently to the same changes in environmental conditions
ex. Not all individuals in a population in a disease outbreak are equally affected; some may not show symptoms, some may have mild symptoms, or some may be naturally immune and resistant to the disease
Allelic variation within a population can be modeled by the Hardy-Weinberg equation The diversity of species within an ecosystem may influence the stability of the ecosystem Natural and artificial ecosystems with fewer component parts and with little diversity among the parts are often less resilient to changes in the environment.

Keystone species, producers, and essential abiotic and biotic factors contribute to maintaining the diversity of an ecosystem. The effects of keystone species on the ecosystem are disproportionate relative to their abundance in the ecosystem, and when they are removed from the ecosystem, the ecosystem often collapses. Variation in molecular units
provides cells with a wider range of functions Variations within molecular classes provide cells and organisms with a wider range of functions.
Diversity of antibodies that can respond to specific antigens

Multiple copies of alleles or genes (gene duplication) may provide new phenotypes
A heterozygote may be a more advantageous genotype than a homozygote under particular conditions, since with two different alleles, the organism has two forms of proteins that may provide functional resilience in response to environmental stresses
Gene duplication creates a situation in which one copy of the gene maintains its original function, while the duplicate may evolve a new function.

Full transcript

Big Idea 2: Energy

Biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis

Enduring Understanding 2.A. Growth, reproduction and maintenance of the organization of living systems require free energy and matter

2.A.1: All living systems require constant input of free energy
2.A.2: Organisms capture and store free energy for use in biological processes
2.A.3: Organisms must exchange matter with the environment to grow, reproduce and maintain organization

Enduring understanding 2.B: Growth, reproduction and dynamic homeostasis require that cell create and maintain internal environments that are different from their external environments

2.B.1: Cell membranes are selectively permeable due to their structure
2.B.2: Growth and dynamic homeostasis are maintained by the constant movement of molecules across membranes.
2.B.3: Eukaryotic cells maintain internal membranes that partition the cell into specialized regions

Enduring understanding 2.C: Organisms use feedback mechanisms to regulate growth and reproduction, and to maintain dynamic homeostasis.

2.C.1: Organisms use feedback mechanisms to maintain their internal environments and respond to external environmental changes.
2.C.2: Organisms respond to changes in their external environments.

Enduring understanding 2.D: Growth and dynamic homeostasis of a biological system are influenced by changes in the system’s environment

2.D.1: All biological systems from cells and organisms to populations, communities and ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy
2.D.2: Homeostatic mechanisms reflect both common ancestry and divergence due to adaptation in different environments
2.D.3: Biological systems are affected by disruptions to their dynamic homeostasis.
2.D.4: Plants and animals have a variety of chemical defenses against infections that affect dynamic homeostasis.

Enduring understanding 2.E: Many biological processes involved in growth, reproduction and dynamic homeostasis include temporal regulation and coordination.

2.E.1: Timing and coordination of specific events are necessary for the normal development of an organism, and these events are regulated by a variety of mechanisms
2.E.2: Timing and coordination of physiological events are regulated by multiple mechanisms.
2.E.3: Timing and coordination of behavior are regulated by various mechanisms and are important in natural selection.


Sample Learning Objectives

explain how biological systems use free energy based on empirical data that all organisms require constant energy input to maintain organization, to grow and to reproduce

predict how changes in free energyavailability affect organisms, populations and ecosystems

construct explanations of the mechanisms and structural features of cells that allow organisms to capture, store or use free energy

use calculated surface area-to-volume ratios to predict which cell(s) might eliminate wastes or procure nutrients faster by diffusion

construct models that connect the movement of molecules across membranes with membrane structure and function

explain how internal membranes and organelles contribute to cell functions.

analyze data to identify possible patterns and relationships between a biotic or abiotic factor and a biological system

The student can create representations and models to describe immune responses


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