Theory Flashcards
What did Earth’s Atmosphere consist of:
- Water Vapor
- Hydrogen Gas
- Ammonia
- C02
- Methane
- limited free Oxygen
What was mixed in the Milley-Urey Experiment
Water, hydrogen, methane, and ammonia.
Result: 15% of the C mixture was converted into organic compounds such as: amino acids, urea, and fatty acids
Why couldn’t life start on earth again?
Because present atmosphere is strongly oxidizing. Molecules necessary for life can’t be synthesized outside of the cell: unstable in the presence of O2.
5 theories of Darwin
1) Perpetual Change
2) Common Descent
3) Multiplication of Species
4) Gradualism
5) Natural Selection
* First 3 are widely accepted
Difference between fragmentation and budding
Each fragment from fragmentation grows into new independent parts and regenerates unlike budding.
3 types of sexual reproduction
1) Bisexual reproduction
2) Hermaphroditism
3) Parthenogenesis
What is the evidence for common descent?
Developmental Homologies.
Describes the comparison of pharyngeal arches of four different embryos at the early stages of development.
What is Cleavage?
When the embryo divides repeatedly without growth (skips G-phase of mitosis). The zygote subdivides.
Zygote -> Blastula
Which pole of the egg has the most yolk?
The vegetal pole
4 types of Yolk Placement:
1) Isolecithal: Very little yolk, evenly distributed
2) Mesolecithal: moderate amount of yolk concentrated at vegetal pole.
3) Telolecithal: abundance of yolk deeply concentrated at the vegetal pole.
4) Centrolecithal: Large centrally located mass of yolk.
What developmental pattern is associated with large amount of yolk?
Direct development. Goes straight from embryo to mature adult.
EXPECTION IN MAMMALS
What yolk placement patterns are associated with Holoblastic cleavage patterns?
Isolecithal and Mesolecithal
What is the name of the process of which the blastula bends inwards?
Invagination
Which organisms have only 1 germ layer
Sponges
Which organisms have two germ layers (Diploblastic)
sea sponges, sea anemones, corals, and comb jellies
What is the first event in organogenesis
Formation of the nervous system (formed from the ectoderm)
What is the first functional organ
The heart (formed from the mesoderm)
What are the different ways to categorize metazoans?
1) Fate of Blastopore
2) Cleavage Patterns
3) Fate of Cells
4) Mesoderm Formation
How is the coelom formed during Schizocoely
Mesodermal cell division (mesoderm are formed first)
How does the coelom form during Enterocoely
Mesoderm and coelom form at the same time. Archenteron elongates and the sides push out outward and expand into a pouch-like coelomic compartment. Pouch-like compartment pinches off.
What body plan(s) does Enterocoely form
Only coelomate
Can cells grow when separated from mosaic development
No, they require positional information from neighbouring cells.
Conditional Specification is associated with that type of development
Regulative Development
How are species named?
Genus (first letter capitalized) + Species (all lower case)
What is the Hierarchy of Taxonomy
1) Domain
2) Kingdom
3) Phylum
4) Class
5) Order
6) Family
7) Genus
8) Species
What fall under the domain of Prokaryota
Bacteria and Archea (no nuclear membrane)
What are the 6 Kingdoms?
1) Animalia
2) Plantae
3) Fungi
4) Protista
5) Bacteria
6) Archea
What are Protozoa
Unicellular eukaryotes (used to be considered a Phylum, but no longer are). Paraphyletic group
Which organisms possess a trochophore larvae
Platyhelminthes, Annelida, Mollusca (Lophotrochozoan Protostomes)
Which organisms shed their cuticle as they grow
Nematoda and Arthropoda (Ecdysozoan Protostomes)
Where is the mouth formed in Protostomes
Where the blastopore was
What type of cleavage pattern do Deuterostomes exhibit
Radial cleavage (in most instances)
What type of development is seen in Lophotrochozoan Protostomes
Mosaic Development
How is the coelom formed in Deuterostomes
By enterocoely
Disadvantages of being unicellular
Limited size, Shorter life span, No division of labour
Modes of locomotion in Uni. Eukaryotes
Flagella (whiplike organelle)
Cilia (hair like organelle that moves particles along the cell surface)
What are cilia and flagella collectively referred as
Pseudopodia (locomotion and engulfing food)
How do Amoebas travel
using pseudopodia
How do Heterotrophs get energy
By consuming other life
What do Saprozoic feeders ingest
Food in soluble form (not visible)
What is the cell mouth in unicellular eukaryotes called
Cytostome
What is the site where indigestible matter is expelled called
Cytoproct
How do paramecium reproduce sexually
Bu conjugation (the exchange of chromosomal material via cytoplasmic bridges between bacteria).
How do micronuclei divide
Mitotically
What is amitotic cell division
When the nucleus and cytoplasm divide without forming a spindle or condensation of chromosomes
What does not occur inside an Intermediate host
Maturation and sexual reproduction
What is the difference between sporogony and schizogony
Schizogony (multiple fission): sporozoite (n) -> many merozoites (n)
Sporogony (special case of schizogony): Zygote (2n) -> Many sporozoites (n)
What makes up the cell wall in fungi
Chitin
What are some examples of Photoheterotrophs
purple and green non-sulfur bacteria
What type of digestion do fungi use
Extrecellular digestion
What type of symmetry do Porifera exhibit
Radial or no symmetry
What are ostia
Pores which allow the flow of water in Porifera
What are oscula
Water outlets
What are the three forms of porifera
Asconoid (flagellated spongocoel)
Syconoid (flagellated canals)
Leuconoid (flagellated chambers)
Where does the water flow to before reaching the radial canals in Porifera
Prosopyles
Where does the water flow to before reaching the spongocoel in Porifera
Apopyles
What are spongocoel
The large central cavity of sponges where water enters
What are Pinacocyte
Epithelial type cell (thin tissue forming the outer layer).
What are Choanocyte
Flagellated collar cells. Move water, collect food particles and consume via phagocytosis.