Unit 2 Flashcards
Morphological Species Concept
group of individuals that appear identical by appearance
Phylogenetic Species Concept
Smallest group of individuals descended from a common ancestor, possess a combination of shared derived traits
Biological Species Concept
1 or more populations of individuals
-Produce viable, fertile offspring
-Are reproductively isolated from other populations
Prezygotic reproductive barriers
Pre-mating: Habitat Isolation, Behavioral Isolation, & Temporal Isolation
Post-mating: Mechanical Isolation & Gametic Isolation
Habitat Isolation
species occupy different habitats within overlapping ranges & rarely encounter each other.
Behavioral Isolation
operates through courtship rituals & other behavioral patterns
Ex: Mate Selection
Temporal Isolation
species breed during different times/seasons
Mechanical Isolation
Morphological differences prevent mating
Gametic Isolation
Sperm Can’t fertilize egg
Postzygotic reproductive barriers
Reduced hybrid viability & reduced hybrid fertility
Reduced hybrid viability
hybrid zygotes fail to develop or reach sexual maturity
Reduced hybrid fertility
hybrid sterility – hybrids can’t produce normal gametes
Colony
collection of individual cells – connected but show little/no differentiation
Chlamydomonas cells
Due to tweaking of genes from gonium & Pandorina
2 Requirements of multicellularity
-Cell communication
-Cell Adherence (Cadherence)
Secondary Endosymbiosis
Eukaryote takes in another eukaryote
Primary endosymbiosis
Eukaryote takes in prokaryote
Four supergroups of Protists
Excavata, SAR, Archeaeplastida, Unikonta
Endosymbiont
cell that lives within another cell – engulfed cell forms mutualism, merged into single organism
Alpha proteobacterium >
Mitochondria
Cyanobacterium >
Chloroplasts
Evidence for Endosymbiont theory
-Inner membranes homologous to prokaryote membranes
-Mitochondria & Chloroplast have 2 membranes, circular DNa & ribosomes
-Grow independently & divide w/in cell
