Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
65 Cards in this Set
- Front
- Back
|
Natural Selection
|
A process in which organisms with certain inherited traits are more likely to survive and reproduce than are individuals with other traits.
|
|
|
Darwin's main points:
|
1. Life evolves
2. Change occurs as a results of "descent with modification" with natural selection as the mechanism |
|
|
Population
|
Natural Selection leads to the changing of: A group of individuals of the same species living in the same place at the same time
-Smallest biological unit that can evolve |
|
|
Evolutionary Adaption
|
Natural Selection leads to: a population's increase in the frequency of traits suited to the environment
|
|
|
Evolution
|
The genetic composition of a population changes over time
|
|
|
Darwins ideas contradicted:
|
1. The earth was relatively young
2. The earth was populated by unrelated species |
|
|
Aristotle & Evolution
|
He believed species are fixed & don't evolve --Christian culture reaffirmed this with a bible interpretation--believing earth may only be 6,000 years old
|
|
|
Fossils & Evolution
|
Fossils took a form of science
-Similarities between fossils & living things - Fossils may be ancient forms of living things -Lamarck believes organisms evolved by the process of adaption by inheriting acquired characteristics --INCORRECT Relative Age: Revealing sequence of species evolving Absolute Age: Radiometric Dating, Etc. |
|
|
Darwin & Lyell
|
Lyell influenced Darwin with principle of gradualism for evolution
-Lyell said the earth is very old |
|
|
Evolution EVIDENCE:
|
1. The fossil record
2. Biogeography 3. Comparative anatomy 4. Comparative embryology 5. Molecular biology |
|
|
THE FOSSIL RECORD
|
- Ordered sequence of fossils found in rock layers
- Reveals appearance in historical context - Fits molecular & cellular evidence that prokaryotes are the ancestors of all life |
|
|
BIOGEOGRAPHY
|
Study of geographic distribution of species that first suggested to Darwin that today's organisms evolved from ancestral forms
|
|
|
COMPARATIVE ANATOMY
|
Comparison of body structure between different species (Evolution is a remodeling process)
- HOMOLOGY- Similarities due to common ancestry - VESTIGIAL structures- Remnants of features that served an important purpose, now have little importance |
|
|
COMPARATIVE EMBRYOLOGY
|
Early stages of development in different animal species reveal homologous relationships
- Supports evolutionary theory |
|
|
Molecular Biology
|
Hereditary background: DNA & proteins encoded in DNA
Evolutionary relationships determined by: Genes & proteins of different organisms |
|
|
Natural Selection
|
- All species tend to produce an excessive amount of offspring
- Organisms vary, and much variation is inheritable (Ex. pesticide- resistant insects) |
|
|
Modern Synthesis
|
Fusion of genetics with evolutionary biology
|
|
|
Gene Pool
|
Total collection of alleles in a population at any one time - When alleles of genes of a population change microevolution occurs
-To determine if a population is evolving you must figure out current allele ratioes |
|
|
Genetic Variations
|
Mutations (Changes in the DNA)
or Sexual Recombination (shuffling alleles during meiosis) |
|
|
Alleles
|
P- ratio of dominant allele in the population
Q- ratio of recessive allele P + Q = 1 Diploid frequencies (1 allele from mother, 1 from father) P^2 + 2PQ + Q^2 = 1 Homo Hetero Homo P- .8 Q- .2 |
|
|
Hardy- Weinberg Formula
|
Calculates % of a human population that carries the allele for a particular inherited disease
-Hardy-Weinberg equilibrium- Non-evoling population |
|
|
PKU
|
Recessive allele that prevents the breakdown of the amino acid phenylalanine (bad in double recessive)
|
|
|
Allele Frequency Changes because:
|
- Mutation
- Random Chance - Immigration or Emigration - Non-random Mating - Natural Selection |
|
|
Causes of Evolutionary Change:
|
- Genetic Drift- A change in the gene pool of a small population by chance
- Gene Flow (genetic exchange w. another population- reduces genetic differences) - Natural Selection (Only one that promotes adaption) |
|
|
Genetic Drift
|
BOTTLENECK EFFECT- Drastic reduction in population size
FOUNDER EFFECT- Few individuals colonize an isolated habitat & represent genetic drift in a new colony |
|
|
Darwinian FITNESS
|
Contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals
|
|
|
3 Outcomes of Natural Selection
|
1. Directional Selection: Shifts the phenotype "curve", selects an extreme phenotype
2. Disruptive Selection: Leads to a balance between 2+ contrasting phenotypic forms in a population 3. Stabilizing Selection: Favors intermediate phenotypes, Most common |
|
|
Sexual Selection
|
- Form of natural selection in which inherited characteristics determine mating preferences
- Sexual Dimorphism- A distinction in appearance between males and females |
|
|
Sickle-Cell Allele
|
- Genetic disorder (affects more blacks)
- Abnormally shaped red-blood cells cause bad complications -Heterozygous individuals for sickle-cell allele don't develop the disease, don't develop malaria |
|
|
Mass Extinction
|
- There have been 5 periods
- We may be living in/contributing to the 6th - Pave the way for new/diverse forms - Take millions of years to recover from |
|
|
MACROEVOLUTION
|
Encompasses the major biological changes evident in the fossil record & formation of new species
-Speciation is the main point |
|
|
Branching & Non-branching Evolution
|
Non-Branching: A population transforms but doesn't create a new species
Branching: (speciation) 1+ new species branch from a parent species - May exist in the same way or change considerably |
|
|
Biological Species Concept
|
"A group of populations whose species have the availability interbreed & produce fertile offspring"
NOT including: fossils & asexual organisms |
|
|
Reproductive Barriers
|
Prevention of sexual reproduction stops gene flow: Prezygotic and postzygotic barriers provide means of isolating gene pools
(Zygote is fertilized egg) |
|
|
PREZYGOTIC BARRIERS:
|
- Temporal Isolation: Timing of mating events is different between parent/daughter population
- Habitat Isolation: Separated by different habitat selection - Behavioral Isolation: Mating rituals differ widely enough - Mechanical Isolation: Sexual apparatus becomes incompatible - Gametic Isolation: Sperm is no longer capable of fertilizing the egg |
|
|
POSTZYGOTIC BARRIERS:
|
- Reduced Hybrid Viability: Hybrid offspring can't survive to reproductive age
- Reduced Hybrid Fertility: Hybrid offspring are often sterile - Hybrid Breakdown: Hybrid offspring aren't as hearty as non-hybrid |
|
|
SPECIATION
|
A population is severed from other populations of the parent species (Reproductive Isolation)
ALLOPATRIC speciation: geographic isolation SYMPATRIC speciation: w.out geographic isolation- genetic change |
|
|
Polyploids
|
Originate from accidents during cell division
Result from hybridization of 2 parent species |
|
|
Tempo of Speciation
|
1. GRADUAL MODEL- Big changes (speciation) occur by steady accumulation of small changes
2. PUNCTUATED EQUILIBRIA- Long periods of little change (equilibrium) punctuated by abrupt periods of speciation |
|
|
Exaption
|
Evolves in one context, but adapts for another function
- Accounts for gradual evolution of novel structures |
|
|
Evolutionary Development
|
Subtle change in development can cause change in: Rate, Timing, & Spatial Pattern of Devleopment
EVO DEVO: Evolutionary Development Biology, study of evolution in developmental processes in multicellular organisms |
|
|
Paedomorphosis
|
Retention into adulthood of features that were solely juvenile in ancestors (Salamanders & Humans)
|
|
|
Homeotic Genes
|
Determine: When, How, Where structures develop
Mutations significantly affect body form |
|
|
Geologic Time Scale
|
Sequence of geologic periods
|
|
|
Plate Tetonics
|
Pangaea (supercontinent 250 mil. years ago)- Shoreline reduced, sea levels dropped, many extinctions occurred
180 mil years ago Pangaea broke up, climates changed |
|
|
Meteor Cause Extinction?
|
Yes
|
|
|
Classifying Diversity of Life
|
SYSTEMATICS: Classify organisms & determine evolutionary relationships
TAXONOMY: Identify, Name, and Classify species |
|
|
Naming Species
|
Each species has a BINOMIAL, 2 part, name consisting of: Genus & Unique Name
(Homo sapiens-italicized) |
|
|
Phylogenetic Trees
|
Depict hypothesis about the evolutionary history of species & reflect hierarchal classification of groups within more inclusive groups
Homologous structures are most helpful |
|
|
Convergent Evolution
|
- Involves superficial similarities in unrelated organisms
- Based on natural selection ANALOGY |
|
|
Molecular Systematics
|
Compares DNA & amino acid sequences between organisms
- Can reveal evolutionary relationships - Sometimes fossils can be compared to living organisms |
|
|
Cladistic Revolution
|
Scientific search for clades
-A CLADE: An ancestral species & all descendants, forms a distinct branch in the tree of life Has changed traditional classifications |
|
|
Classification: Kingdoms
|
Linnaeus- Divided plant & animal kingdoms
Replaced by 5 Kingdoms Replaced by a 3-Domain System: 2 prokaryotes & 1 Eukaryote ...Always changing |
|
|
Eukaryotes & Prokaryotes
|
PROKARYOTES: Began 3.5 Bil years ago & live in great abundance today
EUKARYOTES: 2.1 Bil years ago Multicellular eukaryotes- 1.2 billions years ago |
|
|
BIOGENESIS
|
- All life today arises by the production of preexisting life
SPONTANEOUS GENERATION: Was believed that life arises from nonliving matter TODAY it is believe life was produced by chemical & physical processes |
|
|
4 Stage Hypothesis of Life
(1st organisms were products of chemical evolution in 4 stages) |
1. Abiotic Synthesis of Organic Monomers- Organic molecules for life were created from an apparatus(all amino acids)- can create spontaneously during early earth
2. Abiotic synthesis of Polymers- Drip solutions of organic monomers onto hot sand, clay or rock form polymers 3. Formation of Pre-cells- Isolate abiotically created molecules within a membrane & pre-cells could form w. lifelike properties 4. Origin of self-replicating molecules- process of inheritance |
|
|
Prokaryotes
|
Are ecologically beneficial- recycling carbon & other chemical elements
*Cause 1/2 of all disease- but most are benign or beneficial Have no real nuclei & have exterior cell walls- Most are smaller & unicellular Mobile using flagella - 2 Branches: Bacteria & Archaea |
|
|
Prokaryotes Reproduction
|
Reproduce by BINARY FISSION & at high rates
Some form ENDOSPHERES: thick coated protective walls to prevent unfavorable conditions |
|
|
PROKARYOTIC NUTRITION
|
1. Phototrophs obtain energy from light
2. Chemotrophs obtain energy from environmental chemicals 3. Species that obtain carbon from carbon dioxide are autotrophs 4. Species that obtain carbon from at least one organic nutrient- ex. sugar glucose- are called heterotrophs COMBINE ENERGY SOURCE & CARBON SOURCE |
|
|
Bacteria & Disease
|
PATHOGENS
- Exotoxins: Poisonous proteins secreted by bacterial cells - Endotoxins: are not cell secretions but instead chemical components of the outer membrane of certain bacteria |
|
|
Prokaryotes & Bioremediation
|
Use of organisms to remove pollutants from water, air, or soil --used in sewage treatment
|
|
|
Protists
|
- Eukaryotic (evolved from prokaryotic)
- ancestral to plants, animals, & fungi |
|
|
Origin of Eukaryotic Cells
|
Infolding of a plasma membrane of a prokaryotic cell to form endomembrane system
- Endosymbiosis: 1 species living inside a host species |
|
|
4 Major Categories of Protists
|
1. Protozoans- Live primarily by ingesting food
|
|
|
Algae
|
Photosynthetic protists
- Found in plankton (Unicellular include diatoms & dinoflagellates) - Green Algae is unicellular - Seaweed only similar because convergent evolution |
