43 Cards in this Set
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7 Characteristics of Living Things
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1. Cellular organization
2. Ordered complexity
3. Sensitivity
4. Growth, development, and reproduction
5. Energy utilization
6. Homeostasis
7. Evolutionary adaptation
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Levels of Biological Organization
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1. Atoms
2. Molecules
3. Cells
4. Tissues
5. Organs
6. Organism
7. Population
8. Community
9. Ecosystem
10.Biosphere
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The Nature of Science
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science aims to understand the natural world through observation and reasoning. science begins with OBSERVATIONS.
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Hypothesis
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a possible explanation for an observation.
must be tested to determine its validity
is often tested in many different ways
allows for predictions to be made
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Scientific theory
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is a body of interconnected concepts
is supported by much experimental evidence and scientific reasoning
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Darwin
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His contribution for not evolution but a MECHANISM. He noticed that characteristics of similar species varied from place to place.
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Evidence Supporting Darwin's Theory
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Fossil Record
Earth's age: 4.5 billion yrs old
Mechanism for heredity
Comparative anatomy
Molecular Evidence
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Homologous v. Analogous
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homologous: same evolutionary origin but now differ in structure and function.
analogous: structures or different origin used for the same purpose (butterfly and bird wings)
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Molecular basis of inheritance
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DNA
Sequence of 4 nucleotides encode cell's info.
gene- discrete unit of information
genome- entire set of DNA instructions.
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Structure & Function
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Study Structure to learn function
Know a function - look for that structure in other organisms.
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Evolutionary Change
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3 domains
bacteria- single celled prokaryote
archaea - single celled
eukarya- single celled multicellular eukaryote
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Unifying Themes in Biology
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Cell theory
Molecular basis for heredity
Structure and function
Evolution
Diversity
Cells are information processors
Cells use environmental information
Living systems are in noneq…
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Prokaryotic Cells
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simplest organisms
don't have a membrane-bound nucleus
DNA is present in the nucleoid
archaea & bacteria
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Eukaryotic Cells
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have a membrane-bound nucleus
more complex than prokaryotic
compartmentalization
membrane bound organelles and endomembrane system
cytoskeleton for support and to maintain cell structure.
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Genetic Variation
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differences in alleles of genes found within individuals in a population
raw material for natural selection
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Natural Selection
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organisms that better adapted to their environment tend to survive and produce more offspring. Charles Darwin. Main process that brings about evolution.
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Lamarck
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believed in evolution by inheritance of acquired characteristics.
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Chromosomal Basis of Inheritance
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...
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Hardy-Weinberg Principle
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changes in allele frequency
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Hardy-Weinberg Equilibrium
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Original proportions of genotypes do not change in a population if:
no mutation takes places
no genes are transferred
random mating is occurring
the population size is very large
no selection occurs
LOOK FOR CHANGES IN FREQUENCY
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5 Agents of Evolutionary Change
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Mutation
Gene flow
Non-random mating
Genetic drift
Selection
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Bottleneck Effect (part of genetic drift)
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Drastic reduction in population.
even if organisms do not move from place to place, occasionally their populations may be drastically reduced.
survivors may constitute a random genetic sample of the original population.
results in loss of genetic variability.
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Fitness
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A phenotype with greater fitness usually increases frequency.
survival
mating success
# of offspring per mating
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Heterozygote Advantage
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heterozygotes are favored over homozygotes.
works to maintain both alleles in the population.
Ex: SICKLE CELL ANEMIA
hereditary affecting hemoglobin
homozygotes for sick cell allele usually die before reproducing.
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Horizontal Gene Transfer
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genetic exchange between different species.
genes that confer antibiotic resistance are sometimes transferred between different bacteria species.
was an important part of the process that gave rise to modern species.
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Vertical gene transfer
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progression of changes in a lineage
new species evolve from pre-existing species by the accumulation of mutations
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Darwin's Finches
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finches eat different foods
beaks were shaped differently depending on what kinds of food they are.
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3 conditions of Natural Selection
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variation must exist among individuals in a population
variation among individuals must result in differences in the # of offspring surviving the next generation
variation must be genetically inherited
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Research of Peter and Rosemary Grant
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Studied medium ground finch on Daphne Major
Found beak depth variation among members of the population.
avg. beak depth changed from one year to the next in a predictable fashion.
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Industrial Melanism
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Pollution control resulted in bark color being lighter again
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Fossil Evidence & Types of Dating
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Relative dating (by position) & Isotopic dating (absolute dating)
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Various Intermediate Fossils
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gaps in the fossil record
oldest known bird fossil: archaeopteryx.
four legged aquatic mammal
fossil snake with legs
horse evolution
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Homology
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species that differ as adults often bear striking similarities during embryonic stages. ex: fish, salamander, human.
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imperfections
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some organisms do not appear perfectly adapted. ex:most animals with long necks have many vertebrae for flexibility.
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biogeography
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study of the geographic distribution of species.
Islands: unique species;isolation
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convergent evolution
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similar forms having evolved in different, isolated areas because of similar selective pressures in similar environments.
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Microevolution
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change within a species
natural selection
genetic drift
continuous
leads to adaptations
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Macroevolution
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evolution of new species
extension of microevolution (numerous small changes lead to large changes over time)
other processes
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species
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a group of interbreeding populations that no not normally interbreed with other such groups.
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various species concepts
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genetics
ecological
morphological
evolutionary
biological
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biological species concept
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sexually reproducing populations
exclusively asexually reproducing organisms
works poorly
dandelion
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adaptive radiation
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population in a new environment
several new species arise to exploit available riches
hawaiian silverswords
galapagos finches
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postzygotic idolating mechanism
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ex: hybrid sterility
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BIO 181: EXAM 3