Answer:
The animals present body structure is due to evolution. It is seen in each part including the structure of the heart. The vertebrate heart becomes complex from a simpler form.
Invertebrates, the heart of fishes is two-chambered having one auricle and one ventricle. The deoxygenated blood gets purified in the gills. They are aquatic and no lungs for breathing. The hearts pump a mixture of oxygenated and deoxygenated blood to the body.
The amphibians and reptiles have 3 chambered heart as they lead terrestrial mode of life. The gills modified into the lungs. The left auricle receives pure blood and the right auricle receives deoxygenated blood. The blood purified in the lungs and in the ventricle, both types of blood get a mix. The ventricle pumps the mixed-blood throughout the body.
In the case of birds and mammal, the heart is 4 chambered and the oxygenated and deoxygenated blood are separated. These two are higher vertebrates. No mix of pure and impure blood, the body receives only the oxygenated blood.
This shows to construct the phylogenetic tree of vertebrates - the fishes should be in the bottom, and above it amphibians, reptiles, then, mammals and birds on the top branch of the tree. As the chambers and structure of the hearts modified one after another.
1. Mitosis takes place within somatic cells (cells that make up the body). Meiosis takes place within gamete cells (sex cells).
2. One single division of the mother cell results in two daughter cells. Two divisions of the mother cell result in four meiotic products or haploid gametes.
3. A mitotic mother cell can either be haploid or diploid. A meiotic mother cell is always diploid.
4. The number of chromosomes per nucleus remains the same after division. The meiotic products contain a haploid (n) number of chromosomes in contrast to the (2nd) number of chromosomes in the mother cell.
5. It is preceded by an S-phase in which the amount of DNA is duplicated. In meiosis, only meiosis I is preceded by an S-phase.
6. In mitosis, there is no pairing of homologous chromosomes. During prophase I, complete pairing of all homologous chromosomes takes place.
7. There is no exchange of DNA (crossing-over) between chromosomes. There is at least one crossing-over or DNA exchange per homologous pair of chromosomes.
8. The centromeres split during anaphase. The centromeres do separate during anaphase II, but not during anaphase I.
9. The genotype of the daughter cells is identical to that of the mother cells. Meiotic products differ in their genotype from the mother cell.
10. After mitosis, each daughter cell has exactly same DNA strands. After meiosis, each daughter cell has only half of the DNA strands
Answer:
The correct answer is - Organelles would not receive the products they need to function and materials that were made within the cell would not be able to leave the cell for use.
Explanation:
In the absence of the Golgi apparatus, there would be many changes and negative impact would be on the cell such as lysosome would be lacking also and digestion would not be possible. Golgi apparatus functions as the modifying agent of protein and lipid that come from ER and transport them out of the cells to the desired organ.
The modification and transport of lipid and protein produced would be stopped and might float in the cytoplasm. If the particular organ does would not get the hormone, lipid molecule or particular enzyme, the organ will fail to do its function and homeostasis of organism would be affected.
Natural world beore its use if we consider world before darwin theory, the world was occupied by various individual such as dinasours and primitive plants
Answer:
ecological dominants
Explanation:
In an ecosystem, organisms of same and different species are usually found. However, some organisms appear too commonly than others in that particular ecosystem. These commonly observed organisms (plants and animals) due to their large numbers are called DOMINANT species. An ecological dominant species is that which numerically outshines its competitors in an ecosystem.
A species may be dominant because it is better adapted to certain processes than Its competitors e.g. getting resources, disease resistance etc. or even deters its competitors. Hence, they appear large in number. This is the case of the abundance of pinyon pine and juniper trees along the desert slope of the sierra nevada mountains in california. In that ecosystem, these two plants dominate, hence, will be referred to as ecological dominants.
