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[NSCI 1404] - Final Exam Guide - Comprehensive Notes for the exam (29 pages long!)


Department
Natural Science
Course Code
NSCI 1404
Professor
Mark Botton
Study Guide
Final

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Fordham
NSCI 1404
FINAL EXAM
STUDY GUIDE

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Sexual Selection & the Evolution of Animal Mating Systems
Darwin’s concept of sexual selection
Many species show sexual dimorphism.
Males in sexually dimorphic species often have conspicuous traits such as bright coloration, long
horns or antlers, and complex courtship behaviors.
These traits evolved because they improve the chance of mating success.
Intrasexual selection (male-male competition)
Intersexual selection (female choice)
Another body trait subject to sexual selection is body size.
Larger males may have an advantage in obtaining territories and/or have access to more females
Alternative male mating tactics
If you are not the biggest or most colorful male, you may have little or no chance of mating with a
female.
Are there alternative mating strategies that give these males some chance of success?
Frog mating behavior is well studied for these concepts
external fertilization
amplexus (Once a male frog has found a mate, he needs to take up a position in which he can
fertilize the female's eggs)
vocal signals (convey info about body size; deeper voice is larger and thus more attractive)
seasonal breeding, sometimes temporarily concentrated
How can a small male mate if larger males are present?
The satellite male strategy:
hang out in vicinity of of large male knowing the females will be attracted to their calling; small
doesn't call
intercept the female and tries to mate with her
The mating systems in horseshoe crabs has parallels to frogs
external fertilization, amplexus, mating peaks concede with full moon or new moon phases
Male claspers are used for amplexus; males hold on to female; very difficult to separate clasped male
and female
sexual size dimorphism in horseshoe crabs; males typically smaller but theres a wide range
male body size is not related to mating tactic (mated vs satellite)
This is probably because any male’s clasper span is wide enough to clasp to any female
Random Collision Model used in experiment
Paternity analysis using DNA Markers
If there are no other males present, the attached male has sperm for all eggs
when present, satellite males release sperm and some achieve fertilization
being a satellite is an alternative male mating tactic for those males that do not attach to a female
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Plant Reproduction:
1. What is meant by alternation of generations? What are the differences between sporophytes and
gametophytes? At what point in the plant life cycle does meiosis take place?
The multicellular haploid plant structure is called the gametophyte, which is formed from the spore and
give rise to the haploid gametes. The fluctuation between these diploid and haploid stages that occurs in
plants is called the alternation of generations.
Sporophyte phase produces spores, while gametophyte phase produces gametes (egg and sperms).
Therefore, sporophyte phase is asexual, while gametophyte phase is sexual. Sporophyte is a diploid
phase (2N) due to the formation of zygote, while gametophyte is a haploid phase (N) due to the
occurrence of meiosis.
Meiosis: Between the sporophyte (2n) phase and the gametophyte (n) phase
2. What are the characteristics of sporophytes and gametophytes in the major groups of plants that we
discussed (specifically, mosses, ferns, confers, flowering plants)?
3. You should be familiar with, and be prepared to diagram and discuss, the life cycles of mosses, ferns,
gymnosperms, and angiosperms. Relate life cycle characteristics to the evolution of terrestrial plants
(e.g. why are seed plants much better adapted for terrestrial life than mosses or ferns).
4. In seed plants, what is the difference between the processes of pollination and fertilization?
5. What is the function of double fertilization in angiosperms?
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