bio Flashcards
(40 cards)
Theory of inheritance of acquired characteristics
Interactions between individuals and their environment are important in the evolutionary process
However, it also proposed incorrectly that evolutionary change occurs during the lifetime of single individuals
Giraffe
Homology
Similarities are shared between organisms because they were inherited from the same structures in a common ancestor.
Testing Homology in the similarity of morphology and development
We use homologous traits to reconstruct evolutionary relationships
Ancestral Homology
characteristics that are shared through very remote or distant common ancestry
Derived homology
a feature that is diagnostic for a specific taxon, meaning that feature was acquired by the last common ancestor of that taxon and is shared by all members of the group
Principles of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Analogy
Structures that are similar among organisms in appearance or properties (function) but are inherited from different precursors
Two major categories of classification
Analogy and homology
Adaptive Radiation
When a single kind of organism diversifies to fill different ecological niches
Original species with evolutionary novelty quickly yield descendent species with that novelty
think advantageous trait!
Each descendent represents some new variation on that novelty
Exploit the environment in different ways
Major Modes of Speciation: Cladogenesis
Splitting of one lineage into two or more distinct lineages
Major Modes of Speciation: Anagenesis:
One species evolves over time
Reproductive Isolating Mechanisms: Seasonal isolation
breeding seasons do not correspond
Reproductive Isolating Mechanisms: Sexual isolation
courtship behaviors
Reproductive Isolating Mechanisms: Mechanical isolation
incompatibility in the structure of male and female sexual organs
Reproductive Isolating Mechanisms: Various post-mating mechanisms
Sterility
Biological Species Concept:
Groups of inter-breeding natural populations are reproductively isolated from other such groups.
Reproductive isolation
Physical barriers
Intrinsic barriers
Recognition Species Concept
Emphasizes unique traits or behaviors that allow individual members of the same species to recognize each other for the purposes of mating
Potential mates from different populations may not recognize each other * Coloration, calls, etc.
Ecological Species Concept
A group of organisms exploiting a single ecological niche and natural selection reinforcing species boundaries.
Evolutionary Species Concept
Used to study the fossil record
Defines species as evolutionary lineages (ancestral-descendant sequences of populations) with their own unique identity
Sex cells
Ova, egg cells produced in female ovaries
Sperm, sex cells produced in Male testes
Pass genetic information from one generation to the next
Haploid (N) only contains half the number of chromosomes
zygote - the union between a sperm and an ovum
- meiosis
Somatic Cells
Components of body issues
Duplicate to replace dying cells and repair dying tissues
Diploid (2N) - contains a full complement of 46 chromosomes
- Mitosis
Autosomes:
Responsible for determining traits, and an abnormal number is often fatal.
Sex Chromosomes:
Responsible for the determination of male characteristics in mammals; an abnormal number is not fatal.
Mutation
Only mutations occurring during Meiosis are heritable.
= A problem with DNA replication
copying errors
= the only source of new variation
== Natural selection increases the frequency of positive mutations
== Natural selection decreases the frequency of negative mutations
- mutation is random
Genetic Recombination: Random Assortment
Reshuffling of genetic material from the parents via the random arrangement of chromosomes on the equator of the cell during the first division of Meiosis.
Thus, while each cell ends up with a complete set of chromosomes, unequal amounts have been inherited from father and mother