BIOL 2200 Exam 4 Questions and Answers Already Passed
sexual reproduction - Answers - fusion of haploid gametes to form diploid zygote
- all animals reproduce sexually
asexual reproduction - Answers - clonal formation of offspring
- lacks genetic recombination
- some animals reproduce asexually
fragmentation - Answers - type of asexual reproduction
- fragments break off to become new individuals
- e.g. budding in corals and hydras, fission in sea anemones and flatworms
parthenogenesis - Answers - type of asexual reproduction in which eggs develop without fertilization
- offspring are clones (female)
- mostly restricted to invertebrates because shorter generation times and more offspring per
reproductive event --> beneficial mutations more likely to accumulate
self-fertilization - Answers - male and female gametes from same organism form zygote
- common in plants
- type of sexual reproduction
- lacks genetic recombination
hermaphrodite - Answers having both male and female gametes
what determines an animal's sex? - Answers - birds and mammals: chromosomes
- fish and reptiles: temperature during embryonic development
- insects: varies
pros of asexual reproduction - Answers - great for sessile organisms
- great in stable environments
- may be less costly (see two-fold cost of sex)
cons of asexual reproduction - Answers - reduces genetic variation
- accumulation of deleterious mutations
, two-fold cost of sex - Answers - in a population of females that reproduce asexually, every individual can
produce young
- in a sexual reproducing population, only females have young
- thus, asexual populations reproduce at twice the rate of sexual populations
- selection should favor population with more efficient reproduction strategy
- but this assumes that offspring have equal fitness; not true because asexual organisms are more
vulnerable to disease because their lack of genetic recombination makes it difficult to evolve disease
resistance (rely solely on mutations)
when do animals switch from asexual to sexual reproduction? - Answers when conditions become
stressful and they must become competitive (e.g. increasing density)
external fertilization - Answers - female releases eggs into environment, male fertilizes them with sperm
- usually requires moist habitat
- animals coordinate timing via environmental cues, chemical signals, courtship
synchronous spawning - Answers - type of external fertilization
- reproduction between many individuals
internal fertilization - Answers - sperm deposited in/near female reproductive tract
- often preceded by courtship behavior
- requires compatible reproductive morphology
- embryo develops in egg or is internally gestated
- increased parental care
- animals typically live in dry environments
sperm removal - Answers - specialized structures allow male to remove other sperm from female
- e.g. dragonflies with "scooper"
sperm storage - Answers spermathecae hold sperm, female controls fertilization
sperm plugs - Answers - male secretions that temporarily prevent females from mating with other males
- mostly insects
sex reversal - Answers - change sex for increased mating success
sexual reproduction - Answers - fusion of haploid gametes to form diploid zygote
- all animals reproduce sexually
asexual reproduction - Answers - clonal formation of offspring
- lacks genetic recombination
- some animals reproduce asexually
fragmentation - Answers - type of asexual reproduction
- fragments break off to become new individuals
- e.g. budding in corals and hydras, fission in sea anemones and flatworms
parthenogenesis - Answers - type of asexual reproduction in which eggs develop without fertilization
- offspring are clones (female)
- mostly restricted to invertebrates because shorter generation times and more offspring per
reproductive event --> beneficial mutations more likely to accumulate
self-fertilization - Answers - male and female gametes from same organism form zygote
- common in plants
- type of sexual reproduction
- lacks genetic recombination
hermaphrodite - Answers having both male and female gametes
what determines an animal's sex? - Answers - birds and mammals: chromosomes
- fish and reptiles: temperature during embryonic development
- insects: varies
pros of asexual reproduction - Answers - great for sessile organisms
- great in stable environments
- may be less costly (see two-fold cost of sex)
cons of asexual reproduction - Answers - reduces genetic variation
- accumulation of deleterious mutations
, two-fold cost of sex - Answers - in a population of females that reproduce asexually, every individual can
produce young
- in a sexual reproducing population, only females have young
- thus, asexual populations reproduce at twice the rate of sexual populations
- selection should favor population with more efficient reproduction strategy
- but this assumes that offspring have equal fitness; not true because asexual organisms are more
vulnerable to disease because their lack of genetic recombination makes it difficult to evolve disease
resistance (rely solely on mutations)
when do animals switch from asexual to sexual reproduction? - Answers when conditions become
stressful and they must become competitive (e.g. increasing density)
external fertilization - Answers - female releases eggs into environment, male fertilizes them with sperm
- usually requires moist habitat
- animals coordinate timing via environmental cues, chemical signals, courtship
synchronous spawning - Answers - type of external fertilization
- reproduction between many individuals
internal fertilization - Answers - sperm deposited in/near female reproductive tract
- often preceded by courtship behavior
- requires compatible reproductive morphology
- embryo develops in egg or is internally gestated
- increased parental care
- animals typically live in dry environments
sperm removal - Answers - specialized structures allow male to remove other sperm from female
- e.g. dragonflies with "scooper"
sperm storage - Answers spermathecae hold sperm, female controls fertilization
sperm plugs - Answers - male secretions that temporarily prevent females from mating with other males
- mostly insects
sex reversal - Answers - change sex for increased mating success
