Bio2

Question 1

animals

Answer 1

Animals are classified based on Body symmetry, Embryological development, Segmentation, Limbs, Body plans, and Levels of organization, and backbone. Porifera has no symmetry. Humans, part of the clade hominids, split from chimps five million years ago and were bipedal by 4 million years ago. The first evidence of stone tools was 3.4 million years agi and the first members of homo appeared 2 million years ago. Tools for hunting increased the amount of meat available which was a rich source of nutrients which allowed brains to grow large. Humans left Africa 50 thousand years ago and every species in homo other than Homo sapiens died by 25,000 years ago

Question 2

Viruses

Answer 2

Small pathogens that control populations of other organisms. They are classed based on DNA or RNA in their capsid and are non living since they don’t grow, use energy or reproduce without a host-. They reproduce in the lytic and lysogenic cycles. In the lysogenic cycle a virus enters a cell (it’s surface receptors must be right in order to do so) and replicates with that cell untill a trigger sets it into the lytic cycle. The lyric cycle takes under an hour and has five stages: attachment, entry, replication, assembly and release. Bacteriophages have the unique ability to keep their protein capsule outside of a cell while injecting their DNA into it. The body of a bacteriophage is made of a collar sheath. Viruses could be beneficial since they can inject drugs into cells, however this might cause an unwanted immune response.

Question 3

Lichens

Answer 3

Those are symbiotic combinations of Fungi and Cyanobacteria or green algae. They can grow on bare rocks.