Download encouraging diversity : mcroevolution via selection

Syllabus: Speciation
AP Biology
2015-16
Content
EK
standard
Macroevolution Speciation &
extinction
Reproductive
barriers, isolation
1.C.1
1.C.2
1.C.3
Understanding
Relationships
1.B.2
1.A.4
2.B.3
2.B.1
Phylogenetic
trees/cladograms
Domains of life
Text notes
17.1 – 17.3
questions
‘Reviewing this
Chapter’ # 1 – 6
‘Thinking
Scientifically’ # 1 –
2
1.2
19.1 – 19.3
‘Reviewing this
Chapter’# 1 - 3, 5,
7–9
Vocabulary
Speciation
Adaptative radiation
Biological species
concept
Morphological species
concept
Ecological species
concept
Allopatric speciation
Sympatric speciation
Hybrid
Geographic isolation
Temporal isolation
Mechanical isolation
Behavioral isolation
Viable
Fertile
Pre-zygotic isolating
mechanisms
Post-zygotic isolating
mechanisms
Punctuated equilibrium
Gradualism
Systematics
Taxonomy
Binomial nomenclature
Phylogeny
Cladogram
Outgroup
Bacteria
Archaebacteria
Eukarya
Protista
Plantae
Fungi
Animalia
Cell Wall
Chitin
Cellulose
Peptidoglycan
MACROEVOLUTION
ENDURING UNDERSTANDING 1.C:
LIFE CONTINUES TO EVOLVE WITHIN A CHANGING ENVIRONMENT.
Speciation and extinction have occurred throughout the Earth’s history, and life continues to evolve
within a changing environment. However, the rates of speciation and extinction vary. Speciation can
be slow and gradual or, as described by punctuated equilibrium, can occur in “bursts” followed by
relatively quiet periods. At times of ecological stress, extinction rates can be rapid, and mass
extinctions are often followed by adaptive radiation, the rapid evolution of species when new habitats
open. Scientific evidence, including emergent diseases, chemical resistance and genomic data,
supports the idea that evolution occurs for all organisms and that evolution explains the diversity of
life on the planet.
A species can be defined as a group of individuals capable of interbreeding and exchanging genetic
information to produce viable, fertile offspring. New species arise when two populations diverge
from a common ancestor and become reproductively isolated. Although speciation can occur by
different processes, reproductive isolation must be maintained for a species to remain distinct.
Evidence that speciation has occurred includes fossil records and genomic data.
ESSENTIAL KNOWLEDGE 1.C.1: Speciation and extinction have occurred throughout the
Earth’s history.
a.
b.
Speciation rates can vary, especially when adaptive radiation occurs when new habitats
become available.
Species extinction rates are rapid at times of ecological stress. [See also 4.C.3]
Illustrative examples:
•
Five major extinctions
•
Human impact on ecosystems and species extinction rates
✘ No names and dates of these extinctions
 ESSENTIAL KNOWLEDGE 1.C.2: Speciation may occur when two populations become
reproductively isolated from each other.
a.
Speciation results in diversity of life forms. Species can be physically separated by a
geographic barrier such as an ocean or a mountain range, or various pre-and post-zygotic
mechanisms can maintain reproductive isolation and prevent gene flow.
b.
New species arise from reproductive isolation over time, which can involve scales of
hundreds of thousands or even millions of years, or speciation can occur rapidly through
mechanisms such as polyploidy in plants.
ESSENTIAL KNOWLEDGE 1.C.3: Populations of organisms continue to evolve.
a.
Scientific evidence supports the idea that evolution has occurred in all species.
b.
Scientific evidence supports the idea that evolution continues to occur.
Illustrative examples:
• Chemical resistance (mutations for resistance to antibiotics, pesticides, herbicides
chemotherapy drugs occur in the absence of the chemical)
or
• Emergent diseases
• Observed directional phenotypic change in a population (Grants’ observations of
Darwin’s finches in the Galapagos)
• A eukaryotic example that describes evolution of a structure or process such as: heart
chambers, limbs, the brain and the immune system
UNDERSTANDING RELATIONSHIPS
ENDURING UNDERSTANDING 1.B: ORGANISMS ARE LINKED BY LINES OF
DESCENT FROM COMMON ANCESTRY.
Organisms share many conserved core processes and features that are widely distributed among
organisms today....The existence of these properties in organisms today implies that they were
present in a universal ancestor and that present life evolved from a universal ancestor.
Phylogenetic trees graphically model evolutionary history and can represent both acquired traits
and those lost during evolution.
ESSENTIAL KNOWLEDGE 1.B.2: Phylogenetic trees and cladograms are graphical
representations (models) of evolutionary history that can be tested.
a. Phylogenetic trees and cladograms can represent traits that are either derived or lost due to
evolution. To foster student understanding of this concept, instructors can choose an illustrative
example such as:
•Number of heart chambers in animals
• Opposable thumbs
• Absence of legs in some sea mammals
b.
Phylogenetic trees and cladograms illustrate speciation that has occurred, in that
relatedness of any two groups on the tree is shown by how recently two groups had a common
ancestor.
c.
Phylogenetic trees and cladograms can be constructed from morphological similarities of
living or fossil species, and from DNA and protein sequence similarities, by employing computer
programs that have sophisticated ways of measuring and representing relatedness among
organisms.
d.
Phylogenetic trees and cladograms are dynamic (i.e., phylogenetic trees and cladograms
are constantly being revised), based on the biological data used, new mathematical and
computational ideas, and current and emerging knowledge.
ESSENTIAL KNOWLEDGE 1.A.4: Biological evolution is supported by scientific evidence
from many disciplines, including mathematics.
b. Molecular, morphological and genetic information of existing and extinct organisms add to
our understanding of evolution. Evidence of student learning is a demonstrated understanding of
each of the following:
4.
Mathematical models and simulations can be used to illustrate and support
evolutionary concepts. To foster student understanding of this concept, instructors can
choose an illustrative example such as:
Graphical analyses of allele frequencies in a population
Analysis of sequence data sets
Analysis of phylogenetic trees
Construction of phylogenetic trees based on sequence data
ENDURING UNDERSTANDING 2.B: GROWTH, REPRODUCTION AND DYNAMIC
HOMEOSTASIS REQUIRE THAT CELLS CREATE AND MAINTAIN INTERNAL
ENVIRONMENTS THAT ARE DIFFERENT FROM THEIR EXTERNAL ENVIRONMENTS.
ESSENTIAL KNOWLEDGE 2.B.3: Eukaryotic cells maintain internal membranes that
partition the cell into specialized regions.
c.
Archaea and Bacteria generally lack internal membranes and organelles and have a cell wall.
ESSENTIAL KNOWLEDGE 2.B.1: Cell membranes are selectively permeable due to their
structure.
c. Cell walls provide a structural boundary, as well as a permeability barrier for some
substances to the internal environments. Evidence of student learning is a demonstrated
understanding of each of the following:
1.
Plant cell walls are made of cellulose and are external to the cell membrane.
1.
Other examples are cells walls of prokaryotes and fungi.