If two populations do not interbreed in nature (or fail to produce fertile offspring when they do) they belong to different species
Morphological species concept
All individuals of a species share measurable (quantitative) traits that distinguish them from individuals of other species
Limitations of morphological species concept
Not always accurate - some closely related species are nearly identical in their appearance
Some members of the same species show a great amount of variety
Does not reveal evolutionary relationships
Phylogenetic species concept
Species are defined as a cluster of populations that emerge from a shared recent evolutionary history (they share similar genetics)
Limitations of phylogenetic species concept
It is a new concept
Uses both morphological and genetic sequence data
Reproductive isolation
Prevents individuals of different species from mating and producing successful progeny
Prezygotic isolating mechanisms
Ecological isolation
Temporal isolation
Behavioral isolation
Gametic isolation
Mechanical isolation
Postzygotic isolating mechanisms
Hybrid inviability
Hybrid sterility
Hybrid breakdown
Allopatric speciation
Occurs when a species separates into two separate groups that are isolated from one another
Sympatric speciation
The process through which new species evolve from a single ancestral species while inhabiting the same geographic region; the species become isolated from each due to breeding preferences
Humans are not descended from monkeys or any other primate living today however humans share a common ancestor
Paraphyletic group
Includes the most recent common ancestor of the group
Monophyletic group
Includes the most recent common ancestor of the group and all of its descendants (clade)
Polyphyletic group
Does not include the most recent common ancestor of all members of the group
Plasmids
Circular DNA molecules that are found in the cytoplasm, giving the cells a particular advantage that they would otherwise not have
Different kinds of plasmids
Resistance plasmids
Degradative plasmids
Col plasmids
Virulence plasmids
Fertility plasmids
Gram positive bacteria
Cell wall consisting of a thick peptidoglycan layer
Gram negative bacteria
Cell wall consisting of a thin peptidoglycan layer
Cyanobacteria were the first organisms to use photosynthesis; critical to the abundant accumulation of oxygen in the atmosphere
Types of horizontal gene transfer
Conjugation
Transformation
Transduction
Three branches of archaea
Methanogens
Extreme halophytes
Extreme thermophiles
Six supergroups of protists
Excavata
Chromalveolata
Rhizara
Archaeplastida
Amoebozoa
Opisthokonta
Characteristics and diversity of protists
Habitat
Structure
Movement
Metabolism
Reproduction
Cytoplasmic streaming
The cytoplasm flows through the hyphae, allowing for the transport of food to all parts of the fungus
Types of asexual reproduction in fungi
Fragmentation of hyphae
Budding
Asexual Spores
Sexual reproduction in fungi
Takes place when genetically different mating types (+ and -) come together (fuse) resulting in the formation of a diploid (2n) zygote
It is believed that all land plants evolved from green algae, specifically Spirogyra
The dominant generation in bryophytes is the diploid sporophyte
Types of asexual reproduction in fungi
Fragmentation of hyphae
Budding
Asexual Spores
Fragmentation of hyphae
Hyphae breaks away from the mycelium and grow into separate individuals
Budding
As in yeast
Yeast
Single celled fungi
Asexual Spores
Sporangia or conidia (dust)
Sexual Reproduction in fungi
Genetically different mating types (+ and -) come together (fuse) resulting in the formation of a diploid (2n) zygote
All land plants evolved from green algae, specifically Spirogyra
Algae
An informal term for a large, diverse group of photosynthetic eukaryotic organisms