Human Body Systems
This system uses hormones to regulate body functions over a long period of time.
endocrine system
This molecule carries genetic instructions from DNA to the ribosome
mRNA
This term refers to any change in the DNA sequence
mutation
Structures that are similar in structure but different in function suggest common ancestry.
homologous structures
Capability of an ecosystem to resist change
resistance
This part of the brain controls thinking, memory, and voluntary actions.
cerebrum
This process copies the DNA code into mRNA
transcription
A point mutation that changes a codon but not the amino acid produced.
silent mutation
This mechanism explains how favorable traits become more common in populations
natural selection
How does biodiversity increase the stability of food webs
by providing alternative food sources and energy pathways when one species declines
This structure allows rapid signal transmission between neurons using neurotransmitters.
synapse
BONUS
BONUS
A protein is synthesized but is significantly shorter than normal, even though translation begins correctly. What type of molecular change most likely caused this?
nonsense mutation
Lamarck - Theory of Needs, Acquired Traits, Use and Disuse
Darwin - Natural Selection
Why can the loss of a single keystone species cause ecosystem instability even if overall biodiversity is high?
because keystone species have a disproportionately large effect on ecosystem balance
Why do nervous system responses occur faster than endocrine system responses?
because nerve impulses travel directly through neurons while hormones travel through the bloodstream
If a codon changes from UAU to UAA, what immediate effect occurs during translation
protein synthesis stops
Why are frameshift mutations often more harmful than point mutations
because they alter all codons after the mutation site?
Why does genetic diversity increase the long-term survival of a species
because some individuals may survive environmental changes
Predict what would happen to ecosystem stability if biodiversity increases but most species occupy the same ecological niche.
stability would not increase significantly due to high competition and low functional diversity
Why is meiosis essential to the reproductive system but not to the nervous system?
because meiosis produces gametes with half the chromosome number
Why does altering one tRNA molecule not usually stop all protein synthesis
because multiple tRNAs exist for different amino acids?
Why are mutations in gametes more evolutionarily significant than mutations in body cells
because gamete mutations can be inherited
Why does evolution act on populations rather than individuals?
because individuals do not pass on acquired changes, but populations change through allele frequencies
How can invasive species reduce ecosystem stability even if total biodiversity initially increases?
What is because invasive species disrupt existing interactions and outcompete native species