Answer & Explanation:
a) a) Mutualistic relationship differs from parasitism because the first one benefits both of the involved organisms. Otherwise, parasitism benefits only one of the organisms and it can harm the host. Therefore, the parasite would have to be smaller than the host and it would be somehow extracting energy from the host.
b) The direction of evolutionary changes would follow some kind of pattern, like coevolution. Therefore, analyzing the phylogenies individually and then contrasting them, would help to understand how the host, as well as the parasite, have been evolving.
c) The phylogeny would also help to understand what changed first, or if they changed together as a result of coevolution.
Answer:
<em>The water vascular system of echinoderms </em><em>functions in locomotion and feeding</em>.
Explanation:
Echinoderms have a unique vascular aquatic system called the <u>ambulacral system. </u>
The ambulacral system refers to a net of fluid-filled channels derived from the coelom with functions related to gas exchange, feeding, stimuli reception, and locomotion. This system acts as a hydro motor apparatus.
The opening to the exterior of this vascular system is through an opening known as madreporite. This structure is united to the circular channel that surrounds the animal´s mouth and from where five radial channels emerge and extend along each arm. Water runs through these structures and makes it possible the gas exchange, feeding, locomotion, and other functions. By hydrostatic pressure, little tubular feet are protruded and retracted and help the animal to move.
Answer:
The presence of organelle DNA in mitochondria and chloroplast supports the theory that mitochondria and chloroplast originated as independent prokaryotic organism.
Explanation:
- The more well documented and generally accepted theory for the origin of eukaryotic organelles is Endosymbiotic Theory. (Margulis 1970).
- Recent evidences justify that organelles have originated from the endosymbiotic association of ingested aerobic and and photosynthetic prokaryote, the precursors of mitochondria and chloroplast respectively.
- Molecular data have played an important role in supporting the xenogenous origin rather than autogenous origin of organelles.
- The idea of independent existence of mitochondria and chloroplast are: they are replicators; they carry genetic information; they have protein synthesising machinery; they have ribosome of prokaryotic type.
- The prokaryotic or bacterial origin of mitochondria and chloroplast is supported by the fact like their DNA is simple ,closed and circular with single point of origin; DNA controls the synthesis of their rRNA and tRNA etc.; They have their own ribosome; antibiotic specificity.
Weather : too cold or too hot due to climate change
Habitat can be destroyed due to natural phenomenon
Prey cut off by physical barrier
Lack of water
