Lecture 12-Adaptive Radiation

Lecture 12-Adaptive Radiation - Lecture 12- Adaptive...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 12- Adaptive Radiation: Plants Eating Animals Breakthroughs Gametangia -provides a protective chamber for egg -ensures zygote remains attached -delayed mitosis led to diploid sporophyte stage -ensured that gametes could develop in a protected environment Stems -water and nutrient transport -allows them to grow further above the ground and in drier areas Stomata -allow for gaseous exchange -on land, needed a way to get gas into the cell since no longer in water -is thought that CO2 levels dropped at the end of the Devonian, so more stomata on body would increase water loss, cooling the plant down (transpiration) Structural Elements -eg, wood -support, protection, allowed for large growth (vertically and in diameter) Leaves -if leaves evolved earlier, would have fried (earth too hot, too dry) -when CO2 levels dropped, leaves could evolve because they would lose less water and could cool themselves more easily -leaves allow for a great surface area, and stomata storage, allowing for more gaseous exchange with atmosphere (water, CO2, O2) -stomata create a pump, or pressure gradient, that produces upward flow in the xylem of the plant; fluid from roots to leaves carries essential nutrients necessary for tissue development (flow multiplies with number of stomata) *Greater nutrient transport necessary for building branches and wood, therefore greater photosynthesis needed as these require a lot of energy to be produced* Roots -operate an ion pump to take nutrients from the soil, put them into the root system and keep them there. Generates “root pressure” that can move the nutrients around the plant
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/04/2009 for the course BIOLOGY 1222 taught by Professor Haffie during the Spring '09 term at UWO.

Page1 / 3

Lecture 12-Adaptive Radiation - Lecture 12- Adaptive...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online