Quiz #3 Flashcards
challenges that would overcome to transition on land
mechanical support, gas exchange and sensory equipment
lines of evidence
fossile evidence, comparative anatomy, development
fossile evidence
help document changes through time
comparative anatomy (homology)
shared feature ( whale, human, and bat)
development (homologies)
what genes turn on and off to control devleopment of limbs
Homologous structures
shared through common ancestry
what ancestor did limbs originate from?
lobe-finned fish, large bone connected to the shoulder and pelvic gridle covered in muscle
What is the comparative approach to when limbs arise?
it provides insight as to what changes occurred long ago like mudskippers
What features in the Tiktalik are suggest that tranistion features from water to land?
flattened head, eyes on top, neck, ribs
What are advantage to having a neck, ribs flattened head, and wrist and shoulder.
Neck: head movement ( flexibility to look around)
Flattened head: eyes on top of head able to peak out of water
Ribs: protected lungs-land breathing
Wrist& Shoulder movement: push up - shallow water
an example of devlopmental?
sonic hedgehog: transplanted tissue from one side of a limb bud to another and devopled 2 sets of digits
-modifying an existing gene in new ways
What are the three plant groups?
Nonvascular plants; liverworts
Seedless vascular plants: Ferns
Seed Plants: Gymnosperms or Angiosperm
What are the key challenges plants faced on the transition from water to land?
mechanical support, dessication (water retention adaptations), transition to new environment new defenses evolve, and reproduction`
What are the advantages for plants during transition?
more sunlight used for photosynthesis
Traits that evolved
waxy cuticle- barrier to prevent water loss
stomata: specialized pores for gas exchange ( close and open—water vapor out —co2 in—o2 out)
What type of conditions might close the stomata?
heat,drought, wind
Plants evolved from….
green alage they are multicellular
Seedless vascular plants
no pollen, seeds, and have vascular tissue
What is vascular tissue?
transportation of nutrients
Xylem
stringy portion of celery; transports water and NPK moving upwards to the rest of the plants
phloem
transports sugars (foods) moving down the plant
Stem advantages
provide mechanical structure, transport water & nutrients, sugars
root advantages
reach water; uptake from the soil to the rest of the plant
leave advantages
positioned to sunlight primary site of photosynthesis= sugars travel to other parts of plants
Seed plants
primary plant we see on land
gymnosperms= cone plant
angiosperms= flower plant
pollen
a male gametophyte enclosed in the pollen wall
gametophyte
gamate (haploid cell) producing phase of plants
Advantages to pollen
can travel through pollinators (farther), move into new environment where water is not required for reproduction, prevents gametes from drying out
who are the pollinators and what attract them?
birds, beetles, butterflies, bats, and bees. The color smell and nectar attract them
Why does timing matter for flowering plants?
flowers are not available bee could be starved and no fertilization for flower
