Class Notes (839,477)
Canada (511,349)
Biology (116)
BIOL 2000 (29)
Lecture 3

Lecture 3-Sept 12.docx

4 Pages
73 Views

Department
Biology
Course Code
BIOL 2000
Professor
Joseph Rasmussen

This preview shows page 1. Sign up to view the full 4 pages of the document.
Description
Sept 12, 2013 Adaptations to Terrestrial and Aquatic Environments  Some adaptations of plants for life on land  Osmotic adaptations of fish for marine life  Adaptations of animals to desert environments  Physical adaptations required for large size  Biochemical adaptation’s to extreme environments  Homeostasis and how is it achieved? Plants evolved  Plants evolved root, vascular systems and stomates to obtain water and nutrients, and pump them through their bodies • Microorganisms live in water and depend on diffusion to feed and cleanse their cell- limited to a mw  Plants pump water and transport nutrients through their vascular system  Transpiration pull is the main pump  Evaporation at the leaf “sucks” water up through the plant  Water vapor o Diffuses from stomates  Water evaporates from mesophyll cells  Tension pulls water into the leaf veins  And through the xylem vessels in the stem  Then through the root o Osmosis and into the xylem Water loss  Controlled by o Waxy leaf cuticle o Stomates on the underside- regulate evaporation  Spines and hairs help dessert plants deal with heat and drought  Still boundary layer that traps moisture and reduces evaporation Plants have difficulty trapping Co2 without losing water (C3 mechanism)  Most plants and algae employ the C3 mode of CO2 uptake o Stomates must remain open for hour- not water efficient  RUBISCO has a low affinity for CO2 but the spongy mesophyll allows free air flow- maximize CO2 capture but high water loss  Adaptation to Arid conditions (C4 mechanism)  PEP-carboxylase has much higher affinity for CO2 than RUBISCO  Stomates mostly closed and mesophyll tightly packed to reduce air circulation keeps CO2 levels in the leaf low and conserves water  Photosynthesis can be highly efficient without water loss, but only occurs in the bundle sheath CAM plants are even more water efficient than C4 Metabolism  Stomates open at night only when transpiration is low  OAA is formed and stored within cell vacuoles  During the day stomates close and OAA is recycled to release CO2 to the Calvin-Benson cycle  Day and night enzyme have different T-optima Marine fish  They live in a dry environment  Water and slat balance is critical problem for fish  Marine fish live in water more
More Less
Unlock Document

Only page 1 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit