Quiz 1 Flashcards
(10 cards)
- Characteristics of Deuterostome embryos
Radial cleavage: Cells divide at 90-degree angles.
Blastopore: Forms anus first then mouth, formation of the gut
Coelom formation: Forms through enterocoely (mesodermal pouches pinch off from the gut)
Five characteristics of chordates
Including information about their function and structures derived from them
Notochord: Flexible rod providing support; becomes vertebral discs in vertebrates. (flexing body is how we move, not inch worming to move)
Dorsal hollow nerve cord: Forms the central nervous system (brain and spinal cord).
Pharyngeal slits: (FEEDING FIRST, BREATHING IS A LATER MECHANISM) Openings in the throat area; form structures like gills in fish or parts of the ear in mammals. (Feeding, food leave through it and respiration)
Endostyle/Thyroid gland: (Mucus secretion) Assists in filter-feeding or regulates metabolism. (Mucus secretion (early), thyroid function (later))
Post-anal tail: Extends beyond the notochord and anus; aids in travel for some species (Extension of body for movement)
Key characters of vertebrate groups, in particular, the first appearances of different features like dermal or endoskeletal bones
Agnathans(WITHOUT JAW): Vertrbrae (carterliage) , gills, cranium, first apperance of dermal bones. (has all cordate fetures)
Gnathostomes (JAW MOUTH): Jaws, paired fins.
Chondrichthyes: Serial tooth replacement, Cartilaginous skeleton,
Osteichthyes(BONY FISH): Internal bone, swim bladder (endoskeletal bones).
Sarcopterygians: Muscular, lobed fins
Sarcopterygian fish vs Actinopterygian fish
Sarcopterygians: Lobe-finned, muscles external to the body.
Actinopterygians: Ray-finned, muscles within the body
Characteristics of ova (egg cells: how do we describe their differences?); what is
anisogamy and why does it matter?
Ova: Large, non-motile, contains yolk for nourishment.
Microlecithal: Small yolk, mesolecithal: moderate, macrolecithal: large.
Anisogamy: Large immobile ova vs small motile sperm (Differences between male (small, motile sperm) and female (large, immobile eggs) gametes.
It’s important because it leads to different reproductive strategies and investment between sexes)
Types of heterochrony (the two broad categories and their subcategories)
Pedomorphosis (CHILD SIZE) (slowing development):
- Neoteny: Slower growth.
- Progenesis: Growth ends earlier.
- Postdisplacement: Growth starts later.
Peramorphosis (BEYOND SIZE) (faster development):
- Acceleration: Faster growth.
- Hypermorphosis: Growth ends later.
- Predisplacement: Growth starts earlier
Allometry vs isometry
Allometry: Different growth rates (e.g., head grows slower than body). Example: Humans
Isometry: Equal growth rates, Example: Gecos
Broad differences in forces animals face when they live on land vs water (what
matters for each?)
Land: Gravity is dominant. Larger animals (e.g., elephants) need strong, thick bones to counter gravity.
Water: Buoyancy reduces gravity’s effect. The main challenge is drag:
- Friction drag: Fluid against skin.
- Pressure drag: Turbulence around the body.
- Profile drag: Combination of both; streamlined shapes reduce drag.
Scaling of length, surface area, volume/mass, and repercussions for animal bodies
Length: Doubles with size.
Surface Area: Increases by 4x when length doubles.
Volume/Mass: Increases by 8x when length doubles.
Repercussions: Larger animals generate more heat (volume-related) but have less surface area to dissipate it. They also need thicker bones to support increased mass.
Tissue responses to mechanical stress (too much stress/too little stress)
Hyperplasia (too much) = more cell division (lots of cells) Increased cell division under very high stress.
Hypertrophy (too much but not as much as hyperplasia) = getting bigger in size, bigger bones (bigger cells) Increase in size due to high stress.
Atrophy (too little) = losing size on tissue, smaller bones (smaller cells) Decrease in size due to low stress.
