Life Histories

Question 1

Life History

Answer 1

The lifetime pattern of growth, development, and reproduction of an organism

Question 2

Reproductive Strategies

Answer 2

Asexual and sexual reproduction

Question 3

Asexual Reproduction

Answer 3

Offspring are genetically identical to the parents, an example of this is budding which eventually creates a clone of the body that separates, parthenogenesis is another way (where the unfertilized egg becomes an embryo on its own)

Question 4

Sexual Reproduction

Answer 4

Offspring are a mix of genetic material from parents, some species that can reproduce sexually can also reproduce asexually such as three species of sharks

Question 5

Hermaphrodites

Answer 5

Where individuals possess male and female organs, can be simultaneous (the nudibranchs) or sequential (some fish, mollusks, and echinoderms)

Question 6

Larval Life

Answer 6

Result of sexual production for many aquatic species, can be planktonic or nektonic, before metamorphosing into adult forms

Question 7

Reproductive Effort

Answer 7

The costs of reproduction per unit of time, includes energy/nutrient requirements, gonad development, mate competition, moving to spawning areas, nesting, parental care // Varies across species, but needs to be balanced to be successful

Question 8

Maximal Fitness

Answer 8

At intermediate reproductive effort, where the fewer number of offspring means higher chance of survival and where the smaller reproductive effort increases parental survival

Question 9

Altricial (Parental Care)

Answer 9

Born sooner (lower stage of development), require more parental care

Question 10

Precocial (Parental Care)

Answer 10

Born later (at a later stage of development), require less parental care

Question 11

Iteroparous Species

Answer 11

Produce offspring more than once in their lives once they reach sexual maturity (there is a pre-reproductive stage, a reproductive stage, and then a post-reproductive stage)

Question 12

Semelparous Species

Answer 12

Reproduce once and then die (salmon are an example of this), rely on the survival of the young to continue the species

Question 13

K Species

Answer 13

Slow and steady, large body size, longer life spans, delayed maturity, low fecundity, few species, constant habitat

Question 14

r Species

Answer 14

Live fast, die young, small body size, early maturity, high fecundity, numerous offspring, variable habitat, high levels of dispersal

Question 15

Suite of Traits Related to Life History

Answer 15

Not always accurate anymore, but still useful concepts, r and K species

Question 16

Dispersal

Answer 16

Movement of organisms between different locations and/or populations, includes migration, colonization, and gene flow // Some organisms can not disperse by themselves and rely on wind, animals, or currents

Question 17

Passive Dispersal

Answer 17

Rely on something else to move you

Question 18

Active Dispersal

Answer 18

You move yourself, like crabs in the intertidal areas, or fish

Question 19

Temporal Dispersal

Answer 19

Dormancy period, did not understand this

Question 20

Human Dispersal

Answer 20

Invasive species

Question 21

Lecithotrophic Larvae

Answer 21

Dispersed only to a small degree by short-lived, yolk-dependent larvae

Question 22

Planktotrophic Larvae

Answer 22

Dispersed great distances by longer-lived plankton-feeding larvae

Question 23

Viviparity (Sharks)

Answer 23

Gives birth alive

Question 24

Oviparity (Sharks)

Answer 24

Born in cases that hold the eggs

Question 25

Ovoviviparity (Sharks)

Answer 25

Eggs hatch inside the mother

Question 26

Dispersal (specifically)

Answer 26

Undirected movement of an individual to a new place

Question 27

Migration

Answer 27

Directed movement between specific places

Question 28

Free spawning

Answer 28

Has a number of costs for planktonic gametes

Question 29

Marine Parental Care

Answer 29

Could have free-swimming larvae, or guard and brood eggs, or brood young within body cavities, or have live birth like mammals

Question 30

Modules (Colonial Individuals)

Answer 30

In algae and corals, this is nonsexual reproduction where the clones are connected to each other and exchange nutrients

Question 31

Why Dispersal

Answer 31

Avoidance of crowding, dispersal to sites that are better trophically, hedging bets over many habitats

Question 32

Environmental Uncertainty

Answer 32

If uncertainty is high, new young will be less likely to survive, so there is a selective force for repeated reproduction (iteroparity) so that at least one year of offspring will survive

Question 33

Diadromous Species

Answer 33

Lives divided between residence within the freshwater parts of estuaries and in the open sea

Question 34

Anadromous Fishes

Answer 34

Spend most of their time in the sea, but breed in freshwater (e.g. salmon, shad, and sea lamprey) // more common in high latitudes

Question 35

Catadromous Fishes

Answer 35

Usually spend adult lives in fresh water or tidal creeks but move to the sea to breed (e.g. a specific genus of eels) // more common in low latitudes

Question 36

Philopatry

Answer 36

Species in which individuals tend to show a propensity to return to the general area of their birth

Question 37

Intrasexual Selection

Answer 37

Males engage in competition with each other for mates

Question 38

Intersexual Selection

Answer 38

Females look for characteristics in males that are attractive for fitness

Question 39

Gonochoristic Species

Answer 39

Species that have two separate sexes

Question 40

Parthenogenesis

Answer 40

The development from unfertilized eggs; it occurs among several disparate phyla of animals

Question 41

External Fertilization

Answer 41

Aquatic species can take advantage of the buoyancy and mobility of the fluid medium to disperse gametes, so direct contact between male and female is not necessary (e.g. with corals)

Question 42

Internal Fertilization

Answer 42

A relatively rare strategy among aquatic organisms since the two sexes either need to join together before adulthood or the adults need to be mobile

Question 43

Univoltine Species

Answer 43

Producing one generation per year, emergence of adults is synchronized to a specific time of year

Question 44

Semivoltine Species

Answer 44

Life cycle extends over two years, emerge as adults at a specific, predictable time of year

Question 45

Multivoltine Species

Answer 45

Several life cycles per year, and are more likely to respond to specific water temperature levels as cues

Question 46

Marine versus Freshwater Strategies

Answer 46

Most marine benthos produce widely dispersing planktonic larvae, yet for river benthos this would be an inappropriate strategy since the offspring would be carried too far downstream

Question 47

Marine Crabs

Answer 47

Produce many thousands of eggs that are released into the water in a larval stage (zoea)

Question 48

Freshwater Crabs

Answer 48

Produce relatively few eggs, with each being considerably large than those of marine species, the female continues to carry the eggs in her abdomen

Question 49

Bivalve Molluscs (Marine)

Answer 49

Practices external fertilization, females release several million eggs that are plankton for 3 weeks to 6 months before settling onto a solid substrate

Question 50

Bivalve Molluscs (Freshwater)

Answer 50

Some species similar to marine cycle // Others: males release sperm into the water and females retain the eggs in pouches in her gills, larval stages practice parasitism on vertebrate hosts // Others: brood the young in the gill cavity of the females

Question 51

Intertidal Gastropods

Answer 51

Release pelagic egg masses (that were fertilized internally) that become plankton, although some species are ovoviviparous (keeping the eggs in a brood chamber until born), and others still produce a benthic egg mass (oviparity)

Question 52

Horsehair Worms

Answer 52

Mainly freshwater as adults, yet the larval stage parasitizes an aquatic host first that then becomes a flying or terrestrial adult (yet the horsehair worm remains as a parasite) // eventually the worm can compel the host to return to the water where the host returns as an adult

Question 53

Digeneans

Answer 53

Each stage of the life cycle requires a host, yet they are aquatic since there is an active free-living larval stage