Topic 11: Homeostasis Flashcards
Define homeostais
the ability to maintain a constant internal environment in response to environmental changes
Define feedback regulation
a change/stimulus causes a physiological response that then modifies the stimulus
What is negative feedback and what does it do?
response reduces stimulus
maintains homeostaisis
What is positive feedback and what does it do?
response amplifies stimulus
does NOT maintain homeostasis
Define osmoregulation and what type of process is it?
regulation of solute and water
passive!
Explain protocells and homeostasis. How does is maintain homeostais?
protocells = not living but do maintain homeostasis
their internal environment is different from outside
purely chemical process - osmosis and diffusion across lipid bilayer
What are paramecium? What type of environment do they live in? What is an important organelle that is has?
unicellular protists (SAR clade)
generally aquatic (freshwater)
[solute] in cell > outside (hypotonic)
water moves in via osmosis
has a contractile vacuole: organelle for osmoregulation
-> pumps water out to maintain water balance, prevents lysis
What phylum are jellyfish in, what type of tissues do they have and how do they maintain homeostasis?
cnidaria diploblastic - 2 adult tissue layers no dedicated circulatory system -> all movement via diffusion -> flat morphology (tissues are flat)
What are land plants adapted for? What are some of their characteristics?
terrestrial environment but still need water
cuticle, stomata, vascular tissue
seed plants: pollen, seeds
What do humans have to maintain via homeostasis? What do we have that helps us maintain homeostasis?
have to maintain gases, pH, water levels, etc
amniotic sac - amniotic fluid has salinity similar to sea water
skin
excretory system
What is convergent evolution?
selection favors similar adaptations
What are the 4 main tissue types in animals?
epithelial
connective
muscle
nervous
What does a conformer do?
allows internal environment to vary with external changes
What does a regulator do?
uses internal mechanisms to control internal conditions, independent of external conditions
What are the 2 major systems that coordinate responses to stimuli?
endocrine - signaling by hormones
nervous - signaling by nerve impulse
