2.7 Multicellularity Flashcards
Define Emergence
Properties that emerge only in parts but must interact with each other to have a function
Define Fitness
Measure of survival and reproduction of a trait or genotype
Define Phenotype
Observable trait
Fixation
Trait or gene or genotype is permanently established
Convergent evolution
Appearance of similar traits not by common ancestry
What are microbial mats? And where are there found?
- They are multilayered sheets of prokaryotes and nutrient rich
- combined with other prokaryotes through their biofilm
-found shallow seabeds
Microbial mats gave birth to what?
- they gave birth to eukaryotes/multicellularity
What is the early evidence of life?
Microbial mats
What are the 3 stages Microbial mats moved through time?
- Relied on hydrothermal vents to supply chemical energy
- Anoxygenic photosynthesis
3 oxygen is photosynthesis
Define anoxygenic photosynthesis
By product is not oxygen
2 Requirements for basic multicullularity
- Cell to cell adhesion (cells form as as unit)
- Intercellular communication ( cells need to talk to each other)
Cynokinesis
Duplication of cells, elongates, then splits
What are the 3 classes of multicullarity prokaryotes
- Filaments
- Aggregates
MMPs
What are Filaments and their characteristics
Formation of long chains of cells which elongate but do not divide
- linear or branches
- single or multiple layers
- origin of clones
- cell differentiation
MMPs
Multicullar Magneotactic prokaryotes
connected by tight intercellular junctions
- prokaryotes
-only obligate multicellular bacteria
-fission of “whole organism”
- out of the 3 classes of multicullaruty in bacteria this is the closest to Mc
Cell Differentation
Cells that become more specialized
- cells can be in different shapes and roles
MMPs how do they rotate?
They rotate through earths magnetic field
What are aggregates and characteristics
Cells are in bedded in a slimy self produced matrix
- biofilms and swarms
-cells with distinct morphologies
-extracellular matrix
-cell differentiation
Proximate causes
Asking ”how”
- molecular mechanisms
Ultimate causes
Asking “why”
- selective advantages
Why are bacteria important in the evolution of multicullularity in eukaryotes ?
we use bacteria to understand important transitions and how they occur
What 2 kind of traits are constrained by physics and natural selection
- Physical constraints - traits must be possible by physical laws
- Selections +. Environment traits constraints - traits must permit organisms to survive and reproduce
What new possiblities does MC enable?
- Differentiation of cells in the division of labor
- more efficient use of resources - Development of structures in different organisms
- Intelligence and thought
2 Disadvantages of MC
- The cost of energy
- costed energy To make new molecules and communicate
- wasn’t able to synthesize new molecules with oxygen tic photosynthesis bc it wouldn’t be able to sustain metabolic process with methane as energy
- costed energy To make new molecules and communicate
- Physical limitations
- less freedom of movement internally (pH inside your body cannot change or u die)
