Chapter 13 & 26 Flashcards
What are the two types of chromosomes
- Sex chromosomes (X, Y)
- Autosomes (the other 22 pairs)
what is a karyotpe
An ordered display of all pairs of chromosomes
How is Meiosis different than Mitosis
Reduces number of chromosomes from diploid to haploid
- Takes place over two cell divisions, resulting in 4 daughter cells
What is the protein that holds sister chromatids together during Prophase I
Cohesins
Steps of Meiosis I in order
- Prophase I
- Metaphase I
- Anaphase I
- Telophase I & Cytokinesis
Steps of Meiosis II in order
- Prophase II
- Metaphase II
- Anaphase II
- Telophase II & Cytokinesis
What is the difference between Meiosis I & II
Metaphase I separates homologous chromosomes, while Meiosis II separates sister chromatids
How many sets of chromosomes do Gametes contain
1 set
Horizontal Gene Transfer (HGT)
When another set of DNA is taken up during asexual reproduction
What is the role of Meiosis in the Ovaries/Testes
Produces gametes for sexual reproduction
Zygote
A fertilized egg
Are zygotes diploid or haploid
Diploid, as they are a fusion of two haploid cells.
What are Sorophytes
They are cells that produce haploid spores through meiosis
What are gameophytes
Spores of sorophytes that grew into a haploid organism through mitosis
What is the sexual life cycle of Fungi like
- Only diploid stage is the single-celled zygote
- Haploid cells grow by mitosis into haploid multicellular organisms
- haploid adults produce gametes by mitosis
What are the two ways by which biologists group organisms
Systematics and Phylogenies
What is Phylogeny, and a Phylogenetic tree
Evolutionary history of a taxonomic group, a graphical summary of it
What are sister taxa
organisms on a phylogenetic tree that share a common ancestor
What are clade
A set of species that descended from a particular common ancestor
What is polytomy on a phylogenetic tree
When more than two species fork from a single ancestor
What is a basal taxon
a species that diverges early in the history of a group and originates near the common ancestor of the group
Phenetics
Classifies organisms based on observable shared morphological characteristics
Cladistics
Provides an objective way of assessing evolutionary relationship
monophyletic
a group of organisms with an ancestor and all of its descendants (a clade)
Polyphyletic
a group of organisms that does not include the most recent common ancestor of the group.
- used when species are grouped together based on similar traits
Paraphyletic
A group of organisms that includes an ancestor but not all of its descendants
Apomorphy
Derived trait that is unique, not present in ancestor
Synapomorphy
Apomorphy (unique derived trait) that a common ancestor and all descendants possess
Plesiomorphy
Ancestral trait shared among a group, including their common ancestor
Autapomorphy
Derived trait unique to a single species, distinguishable from closest relative
Homoplasy
Similar derived traits in distantly related lineage; due to convergent evolution
Maximum Parsimony
A tree that requires the fewest evolutionary events
