Natural Selection

Driving Question: "Should the North Carolina Biology curriculum include evolution?"

Objectives: Explain how fossil, biochemical, and anatomical evidence support the theory of evolution; Explain how natural selection influences the changes in species over time; Explain how various disease agents (bacteria, viruses, chemicals) can influence natural selection; Explain the historical development and changing nature of classification systems; Analyze the classification systems of organisms according to their evolutionary relationships (dichotomous keys, phylogenetic trees)

1.2.3

Explain how specific cell adaptations help cells survive in particular environments (focus on unicellular organisms).

Unpacked:

• Explain how various structures of unicellular organisms help that organism survive. Emphasis is on contractile vacuoles, cilia, flagella, pseudopods, and eyespots.

• Summarize adaptive behaviors – examples include chemotaxis and phototaxis.

2.1.2

Analyze the survival and reproductive success of organisms in terms of behavioral, structural, and reproductive adaptations.

Unpacking:

Analyze how various organisms accomplish the following life functions through adaptations within particular environments (example: water or land) and that these adaptations have evolved to ensure survival and reproductive success.

o Transport and Excretion – how different organisms get what they need to cells; how they move waste from cells to organs of excretion. Focus is on maintaining balance in pH, salt, and water. Include plants - vascular and nonvascular.

o Respiration – how different organisms take in and release gases (carbon dioxide or oxygen, water vapor); cellular respiration

o Nutrition – feeding adaptations and how organisms get nutrition (autotrophic and heterotrophic) and how they break down and absorb foods.

o Reproduction, Growth and Development – sexual versus asexual, eggs, seeds, spores, placental, types of fertilization.

• Analyze behavioral adaptations that help accomplish basic life functions such as suckling, taxes/taxis, migration, estivation, and hibernation, habituation, imprinting, classical conditioning (e.g. Pavlov’s dog–stimulus association), and trial and error learning.

3.4.1

Explain how fossil, biochemical, and anatomical evidence support the theory of evolution.

Unpacking:

• Summarize the hypothesized early atmosphere and experiments that suggest how the first “cells” may have evolved and how early conditions affected the type of organism that developed (first anaerobic and prokaryotic, then photosynthetic, then eukaryotic, then multicellular).

• Summarize how fossil evidence informs our understanding of the evolution of species and what can be inferred from this evidence.

• Generalize what biochemical (molecular) similarities tell us about evolution.

• Generalize what shared anatomical structures (homologies) tell us about evolution.

3.4.2

Explain how natural selection influences the changes in species over time

Unpacking:

• Develop a cause and effect model for the process of natural selection:

o Species have the potential to increase in numbers exponentially.

o Populations are genetically variable due to mutations and genetic recombination.

o There is a finite supply of resources required for life.

o Changing environments select for specific genetic phenotypes.

o Those organisms with favorable adaptations survive, reproduce and pass on their alleles.

o The accumulation and change in favored alleles leads to changes in species over time.

• Illustrate the role of geographic isolation in speciation.

3.4.3

Explain how various disease agents (bacteria, viruses, chemicals) can influence natural selection.

Unpacking:

Develop a cause and effect model for the role of disease agents in natural selection including evolutionary selection of resistance to antibiotics and pesticides in various species, passive/active immunity, antivirals and vaccines.

3.5.1

Explain the historical development and changing nature of classification systems

Unpacking:

• Generalize the changing nature of classification based on new knowledge generated by research on evolutionary relationships and the history of classification system.

3.5.2

Analyze the classification of organisms according to their evolutionary relationships (including dichotomous keys and phylogenetic trees).

Unpacking:

• Classify organisms using a dichotomous key.

• Compare organisms on a phylogenetic tree in terms of relatedness and time of appearance in geologic history