Evolution Flashcards
Descent with Modification
Charles Darwin, species are descendants of ancestral species that were different from present day species
Evolution
change in genetic composition of a population
What does Evolution measure?
Change in allele frequency
What ship did Charles Darwin travel on?
The beagle
What did Aristotle classify organisms into?
Scale of Nature
Carolus Linneaeus
develop binomial naming system and Hierarchy
Hierarchy
Species – genus – family – order – class – phylum - kingdom
What was also part of Darwins ideas
fossils in different layers of rock
Lamarck’s Evolution
compared fossils to present day species and discovered line between them
Lamarck’s Principle
use and disuse, inheritance
Use and disuse
parts of an organism used a lot get bigger and stronger
Inheritance
inheritance of these special characteristics
What was flawed about Lamarck’s Principle
acquired traits can not be passed down to the next generation
Natural Selection
individuals with certain traits leave more off spring than other individuals with out that trait
Adaptations
Characteristics of organisms that enhance their survival and reproduction in specific environments
4 Observations that led to natural selection
- members in the population vary in traits
- traits are inherited by off spring
- Species are able to produce more off spring than the environment can support
- many of these offsprings do not survive
Artificial Selection
Human modification of species over many generations by selecting and breeding individuals that possess desired traits
Two summary of Natural Selection
- Over time natural selection can lead to increase matching of organisms and environment
- Changes in environment could lead to new species via natural selection
Evidence of Evoulation
- Direct Observation of Evolutionary Change
- Fossils can show evolutionary change over time
- Homology
- Biogeography
Law of Succession
Living relatives of fossil species
Fossil Evidence
Law of Succession, Transitional Forms
Homology
Characteristics present in ancestral organism are altered in its descendants
Homologous Structures
Variations of structural theme present in a common ancestor
Vestigial structures
Lost most or all of past function
Convergent evolution
independent evolution of similar features in different lineages
Evolutionary tree
diagram that reflects evolutionary relationships among groups of organisms
Cell Division
All cells must have come from another cell
Why do cells split
Reproduction, growth and development, tissue renewal
Cell Cycle
Life of a cell from when formed to when it divides into two cells
How does most cell division result from
Indentical sister cells, split DNA equally among two resulting cells
Two types of Reproduction
Asexual Reproduction, Sexual reproduction
Asexual Reproduction
creation of genetically identical offspring from one parent
Sexual Reproduction
creation of offspring by fusion of sperm and egg
Binary Fission
Replication of DNA split into two daughter cells
Prokaryotes
Single long DNA molecule
Eukaryotes
DNA packaged into chromosomes(made from chromatin DNA and proteins)
How are Chromosomes distrupted during cell division
long thin fiber when cell is not dividing, Chromosomes begin to condense after DNA replication
What are sister Chromatids
Pairs of indentical chromosomes
Where are the sister Chromatids joined together at
Centromere
Centromere
Specialized region where two sister chromosomes are attached
Phases of Cell Cycle
Interphase, Mitosis, Cytokinesis
Interphase
Cell growth and duplication of DNA
Mitosis
Division of the nucleus, DNA
Cytokinesis
Division of the Cytoplasm
in animals pinching of plasma membrane, in plants form of cell plate during telophase
What is 90% of the cell cycle
Interphase
what are the three Subphases of Interphase
G1 Phase, S phase, G2 Phase
G1 Phase
first gap, cell growth
S phase
Synthesis, Chromosomes duplicated
G2 Phase
Second Gap, cell growth
Miotic Spindle
FIbers of microtubles and proteins, moves DNA by shortening and lengthening the mircotubles
Centrosome
containing material to organize cells microtubles, in cell division it splits into two centrosomes
What are the Stages of Mitosis
Prophase, Prometaphase, Metaphase, Anaphase, Telophase
Cell Size
Cell divide when they roughly double in size
Restriction Point
check points in the cell cycle where the cell decides whether or not to proceed
Heredity
transmission of traits from one generation to the next
Variation
difference among members of the same species
Genetics
scientific study of heredity and hereditary variation
Genes
hereditary units coded information, program the specific traits organisms develop
Chromosomes
unit of heredity, where genes are located
Somatic Cells
those not associated with gamete formation
Homologous Chromosomes
pair of chromosomes with same length, centromere position
Diploid Cells
cell with two sets of chromosomes
what does “n” stand for when referring to chromosomes
it equals number of chromosomes in a single set
Haploid Cells
Cell with one set of chromosomes
what is the life cycle
generation to generation sequence of stages in the reproductive history of an organsim
Meiosis
Modified type of cell division it results in haploid cells
Cross Over
homologous chromosomes exchange sections of chromosomes
Independent Assortment of Chromosomes
Random orientation of homologous pairs during metaphase of meiosis
Chiasma
Region where nonsister chromatids exchange genetic material
Random Fertilization
sexual reproduction can lead to a large number of possible genetic combos
Three parts of Sexual Reproduction
Random fertilization, independent assortment of chromosomes, cross over
Pleiotropy
Gene codes has more than one Phenotypic effect
Epistasis
gene at one locus alters phenotypic expression at second locus
Polygenic Inheritance
additive affect of one or more genes on a phenotype
Recessively inherited disorders
sickle cell, albinism
Dominantly inherited disorders
huntingtons diease and achondroplasia
what is the chromosome theory of inheritance
genes have location along chromosomes, undergo segregation and independent assortment
Nondisjunction
pair of homologous chromosomes do not move apart in meiosis I or sister chromatids fail to separate in meiosis II
Monosomic
missing one copy of a chromosome
Trisomic
an extra third copy of chromosome
polyploidy
more than two sets of chromosome
Triploidy
three sets of a chromosome
tetraploidy
four sets of a chromosome
alterations to chromosome structure
caused by errors in meiosis or damaging agents cause breaking of a chromosome
Four types of changes in chromosome structure
deletion, duplication, Inversion, translocation
XXY
male sex organs are small and some female body characteristics
XYY
some what taller than average
XXX
indistinguishable from XX
Microevolution
evolution below a species level, change in allele frequency in a population
Macroevolution
evolution above species level, includes origins of new species level