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TEXAS STATE / Biology / BIO 4416 / Why are larger animals found more in the ocean than on land?

Why are larger animals found more in the ocean than on land?

Why are larger animals found more in the ocean than on land?


School: Texas State University
Department: Biology
Course: General Ecology
Term: Spring 2019
Cost: 50
Name: Exam 2 review
Description: Covers chapters 7-11. All will be on the test.
Uploaded: 03/23/2019
12 Pages 177 Views 5 Unlocks

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Chapter 7: Animal Adaptations What is scaling and why is it important?

Why can larger animals be found in the ocean than on land?

∙ Scaling is the ratio by which body size changes in a predictable way.  This includes morphological and physiological features as a function of  body size.  

∙    This is important because a surface area to volume relationship must  be maintained.  

o Surface area/Volume relationship is the most critical restraint on  the evolution of animals.  

 Surface area is important for conducting nutrients,  

diffusion of water and oxygen.  

 Volume is critical to metabolism

 If the volume grows faster than the surface area, problems  occur.

How do animals maintain their Surface Area to Volume Ratio? ∙ Increase area → Creasing, wrinkling

How do organisms increase their surface area to volume ratio?

∙ Active transport → tube-like structures in small animals (Insects like  grasshoppers)

 → Lungs and circulatory system; digestive systems in  

larger animals If you want to learn more check out What is the definition of sexual orientation?
We also discuss several other topics like What is the definition of religion?

Greater Body size = increased complexity in adaptations 

Why can larger animals be found in the ocean than on land?  ∙ Larger animals, such as whales, can be found only in the oceans due to the buoyancy properties of water.  

∙ On land, the force of gravity would require too large and heavy a bone  structure to support the mass of a large terrestrial animal

In which style of eating does quality matter?

∙ Herbivores (non-meat eaters)

In which style of eating does quality matter?

What are the different types of herbivores?

∙ Grazer → leafy material

∙ Browser → woody material

∙ Granivore → grains and seeds

∙ Frugivores → Fruits

∙ Nectivores → nectar (like butterflies, bees, etc.)

In which style of eating does quantity matter?

∙ Carnivory (meat-eaters) If you want to learn more check out What is innate in psychology?

What do detritovores eat?

∙ Dead and decomposing material  

What is a conformer?

∙ An organism in which external conditions induce internal changes to  the body to match external conditions.

o How long a conformer can survive depends on its tolerance to  change.  

∙ Isotonic with the environment; exhibit slow growth; have low energy  requirements

∙ changes occur at the physiological and biochemical levels ∙ NOT good in homeostasis

What is a regulator?

∙ An organism in which regulation and maintenance of internal  environment occurs within the organism and can occur over a broad  range of external condition.  

∙ High energy requirement – harder to stabilize an internal environment  when external environment is changing (think sweating, shivering,  panting, etc.)

∙ Full-blown homeostasis

∙ First changes usually behavioral (seek shade if too hot, sun if too cold)  then physiological changes We also discuss several other topics like How do porifera acquire food?

∙ Will try to change environments to make regulation easier (burrow,  seek shade, sun, etc.)

What is the homeostasis feedback loop and how does it work? ∙ Negative feedback loop which acts to maintain homeostasis to a  normal or desired point

∙ Variable → Receptor → Integrator → Effector → Variable → etc.  What are the aspects of a feedback loop?

∙ Variable – focus of the regulation (ex. Body temperature) ∙ Receptor – measures internal environment (ex. Nerve receptors) ∙ Integrator – evaluates information from the receptor and determines  how to proceed (brain)

∙ Effector – function to modify the internal environment (hormones,  muscles, etc.)

Why maintain a set temperature?

∙ Enzymes can only function at certain temperatures

∙ Too high = denature

∙ Too low = can’t function

Why is cellular respiration important? If you want to learn more check out What is the definition of constant return scale?

∙ To break down glucose

∙ Synthesis of ATP for energy

What are the aspects of cellular respiration?

∙ Glycolysis, Krebs cycle, electron transport chain

Which parts of cellular respiration require oxygen and why? ∙ The electron acceptor at the end of electron transport chain ∙ To form water

What is the pattern through evolution in regards to oxygenation?

∙ Absoprtion via skin → gills/trachea → lungs

∙ Simple organisms = skin for respiration

∙ Complex organisms = lungs  

∙ Some organism (ex. Frogs) utilize their skin as well as lungs How do organism who live in anaerobic environments survive? ∙ Some utilize sulfur

∙ Some just perform glycolysis

∙ Rely on fermentation processes.  

What is water balance?

∙ The difference between the uptake and loss of water

∙ Water balance is critical to survival. Too much or too little will result in  death.  

How do terrestrial animals uptake water?

∙ Drinking (mostly), eating, metabolic water from cell respiration (least) How do terrestrial animals lose water? We also discuss several other topics like What is the teotihuacan?

∙ Urine, feces, evaporation through skin (sweating, panting), exhalation What are adaptations for surviving in dry areas?

∙ Evading drought (migration)

∙ Estivation – physiological inactivity (similar to hibernation) ∙ Diapause – arrested development (insects, invertebrates, in embryo) ∙ Reduction in respiration, reduction in water loss, production of highly  

concentrated urine and feces, tolerance to certain level of dehydration Why is osmoregulation important for aquatic animals? ∙ Freshwater organisms = hyperosmotic

o Water comes into body

∙ Marine and brackish organisms = hypo-osmotic

o Water leaves body, must drink water to replenish self

∙ Some marine organisms are isosmotic

What is thermoregulation?

∙ Regulation of internal temperatures (regulators)

What are the modes of thermoregulation?

∙ Poikilotherms  

∙ Homeotherms

∙ Ectotherms

∙ Endotherms

What are the only homeothermic endotherms?

∙ Mammals and birds

What are important characteristics of poikilotherms? ∙ Internal temperatures varies

∙ Low metabolic rate and high thermal conductivity  

o Thermal conductivity = ability to exchange heat with the  environment

∙ During stress they can perform anaerobic cellular respiration

∙ Rely on behavioral thermoregulation

∙ Aquatic environment is more conductive to heat

o Poikilotherms in this environments have a thinner layer of  insulation

What are important characteristics of homeotherms? ∙ Internal temperatures are relative stable

∙ Rate of cellular respiration is proportional to body mass ∙ Insulation is important

∙ Evaporative cooling is often utilized

∙ Fur thickness varies with seasons

∙ Fur and feathers absorb heat and prevent heat escape

What are important characteristics of heterotherms? ∙ These animals are capable of shifting between homeothermy and  poikilothermy

∙ During torpor state, homeotherms behave like heterotherms o Torpor state – daily drop in metabolic rates and internal  temperatures

∙ Hibernation = long seasonal torpor  

What is the difference between endotherms and ectotherms? ∙ Endotherms internally generate metabolic heat to maintain internal  temperature

∙ Ectotherms maintain temperature through exchange with the  environment

What is countercurrent circulation?

∙ The exchange of body heat between arterial and venous blood  reaching the extremities

∙ This reduces heal those though body parts or cools the blood flowing to vital organs like the brain  

What is hyperthermia and why do some desert animals utilize it? ∙ hyperthermia is a body temperature way above the normal  temperature

∙ This reduces the difference between the body and the external  temperature (environment)  

∙ It reduced the need for evaporative cooling

What is supercooling and who is it utilized by?

∙ Supercooling is synthesis of glycerol in the bodily fluids to resist  freezing.  

∙ Some cold-tolerant poikilotherms

Chapter 8: Properties of population What is a population?

∙ A group of members of the same species living within a given area

∙ Too small a population can lead to inbreeding

∙ Interbreeding between populations widens the gene pool What is a unitary organism?

∙ An organism with definitive growth forms and longevity ∙ Most animals are unitary

What is a modular organism?

∙ Sexually reproducing parent organism and asexually produced stems  arising from roots

∙ Most plants

∙ Some animals (Hydra)

What are genet and ramet individuals of modular organisms? ∙ Genet – an individual raised from zygote

∙ Ramet – asexually produced by genet (clones)

What is distribution?

∙ The spatial location based on presence of absence of individuals ∙ Can be ubiquitous or endemic

o Ubiquitous – wide spread

o Endemic – localized  

∙ May be looked at over various scales.  

What is geographic range?

∙ A defined area that encompasses all individuals of a population

What is habitat?

∙ The place or environment in which the organism lives.  What are metapopulations?

∙ Subpopulations caused by heterogeneity of habitat within distribution  range.  

What is abundance?

∙ The number of individuals in a population

∙ Determined by 2 factors: density and the area over which the  population is distributed

What is population density?

∙ The number of individuals per area or per volume

What are the 3 types of distribution?

∙ Random – no pattern or uniformity

∙ Uniform – arranged in a pattern

∙ Clumped – no pattern, but individuals are in grouping

What is ecological density?

∙ The number of individuals per unit of available living space How are plants or sessile organisms sampled?

∙ Using sampling units (quadrants)

∙ Average density x area = estimated population size

∙ Clumped distributions may affect sampling

What sampling methods are used for mobile organisms? ∙ Capture-recapture

∙ Mark-recapture

Explain indices of abundance.

∙ Counts of vocalizations, scat, or animal tracks which are used to  measure relative abundance or density.  

∙ Can’t be used as a stand alone method for density, but are useful if the estimates are collected over long periods of time

What is age structure and the 3 main age classes?

∙ Age structure – proportion of individuals in different age classes ∙ 1. Pre-reproductive age

∙ 2. Reproductive age

∙ 3. Post-reproductive age

∙ Length of each stage varies with species

What are some methods of tracking age?

∙ Tracking from birth

∙ Looking at teeth

∙ Growth rings

∙ Plumage changes (birds)

∙ Deposits on scales (fish)

What can stimulate dispersal of individuals?

∙ Crowding, temperature changes, quality and abundance of food,  photoperiods

Chapter 9: Population Growth What is population growth?

∙ Increase or decrease in the number of individuals in the population ∙ Can be positive or negative

What are open and closed populations?

∙ Open population – migration is occurring

∙ Closed population – no migration

Define immigration and emigration.

∙ Immigration – individuals are migrating into the population; entering ∙ Emigration – individuals are migrating out of the population; exiting How do birth and death rates affect growth of a population? ∙ When births = deaths → no growth

∙ When Births > deaths → positive growth (increasing population) ∙ When births < deaths → negative growth (decreasing populati0n) When immigration and emigration are at equilibrium, what affects  population growth?

∙ The birth and death rates

What is a life table?

∙ An age specific account or mortality arranged in table format.  ∙ Age of individual and number of individuals of that age

What is a cohort?

∙ A group of individuals born in the same period of time

∙ Like bins on a histogram

What is survivorship?

∙ The probability at birth of surviving at any given age

What are the variables of a dynamic life table?

∙ x = age

∙ nx = number of individuals

∙ lx = survivorship

∙ dx = number of individuals that have died  

∙ qx = age specific mortality rate

What is a time specific life table?

∙ A table which shows a population sampled at specific time to obtain  distribution of age classes during a single time period

∙ Age stages may be different durations

When it comes to plants, what do we want to know to establish a  time-specific life table?

∙ Seedling mortality and survival

∙ Population dynamics of perennial plants marked as seedlings  ∙ Live cycles of annual plants

What is crude birthrate?

∙ The number of births per 1,000 individuals of a population per unit of  time

What is the gross reproductive rate?

∙ An estimate of the average number of female offspring born to a  female over her lifetime.

What is a better way to look at birthrates?

∙ Looking at the number of births per female of age x and using average  birth rates bx.  

∙ Age-specific birth rates

Define fecundity.

∙ Fertility

What are the variables of a fecundity life table?

∙ lx - survivorship

∙ bx – birth rate

∙ lx bx – the mean number of females born in each age group adjusted for survivorship

∙ R0 – net reproductive rate

What is net reproductive rate?

∙ The average number of females that are produced during a lifetime by  a newborn female.  

∙ Means of evaluating the individual (fitness) and the population  consequences of specific life history

What does a population projection table show?

∙ How a population will change through time

∙ A model to project future population growth (either positive, negative,  or no growth)

∙ Using birth rates and survivorship to create the table and calculate the  data

What does lambda (λ) indicate?

∙ λ = 1 → stable; no growth

∙ λ > 1 → population is increasing in size

∙ λ < 1 → population size is decreasing

Define stable age distribution.

∙ λ becomes constant over all age classes; can become stable at, below,  or above 1

Define stochastic.

∙ randomness

How does stochastics affect population dynamics?

∙ Random variations in birth and death rates can cause departures from  predicted growth.  

∙ Population are more likely to demonstrate demographic stochasticity.  ∙ Environmental stochasticity is usually seen. This affects birth and  death rates and thus population growth

Chapter 10: Life History

What do tradeoffs involve?

∙ Modes of reproduction (sexual, asexual)

∙ Age of reproduction

∙ Allocation of resources to reproduction (how much energy into  reproduction)

∙ Number and size of eggs, young, seeds (lots of small, few large) ∙ Timing of reproduction (once a year, seasonal, twice a year, etc.) What are extrinsic ecological factors?

∙ External factors such as the physical environment, presence of  predators, presence of competitors.  

What are intrinsic ecological factors?

∙ Internal factors such as phenology, patterns of developments,  genetics, and physiology.  

What are pros and cons to asexual reproduction?

∙ Pros: fast, easy, well adapted to environment

∙ Cons: lack of genetic variability, vulnerable to changes in environment What are pros and cons to sexual reproduction?

∙ Pros: increased genetic variability, more likely to survive changes to  the environment

∙ Cons: energetic requirements are higher, must find mates, etc.  Some organisms can cycle between sexual and asexual reproduction predictably. Others will cycle between the two based on  environmental cues

What is a hermaphrodite and what are the different types? ∙ Hermaphrodite – one individual has both male and female reproductive organs.

∙ Simultaneous – animal has both sets of reproductive organs at  reproductive life stage

∙ Sequential – animals can be male or female at different life stages  (some fish)

In plants, what is dioecious and monoecious?

∙ Dioecious – plants have both sex organs on the same plant. May be  located on the same flower (bisexual) or different flowers

∙ Monoecious – each plant has only one type of sex organ Name some costs of sexual reproduction.

∙ Reduced survival: acquisition of mates, defending territory, feeding,  protection of young

∙ Fecundity: loss of body mass and decreased immunity can affect next  breeding season

∙ Growth: can bellowed with reproduction due to energy requirements of  raising offspring; size of mother affects size of litter.

Name a benefit of sexual reproduction.

∙ Increased fitness

When is the payoff in fitness maximized?

∙ When the age and size of maturity are optimized

∙ When the difference between the cost and benefits of maturation at  different ages and sizes is maximized

What will natural selection favor?

∙ The individuals whose age at maturity results in the greatest number  of offspring produced over the lifetime of the individual

What is a plus side to waiting to reach a larger size before  reproducing?

∙ Litter size or size of offspring can be larger

What is a down side to waiting to reach a larger size before  reproducing?

∙ Possibility of death before reproducing

When is early maturation favored?

∙ When adult survival is reduced

When is late maturation favored?

∙ When the juvenile survival are is reduced compared to adult survival Define fecundity.

∙ The number of offspring produced per unit of time (bx)

Define reproductive effort.

∙ The total energetic cost of reproduction per time unit

What is reproductive success?

∙ A product of the number of offspring produced and the probability of  their survival.

Trade-offs occur between which 4 factors?

∙ 1. Number of offspring and their probability of survival

∙ 2. Litter size and number of offspring

∙ 3. Having altricial or precocial offspring

∙ 4. Amount of parental care required after birth

What are precocial and altricial offspring?

∙ Precocial – offspring are ready to take on the world right after birth. o Horse, duck, chicken, giraffe, etc.  

∙ Altricial – offspring are born fully helpless and require full protection  and care from a parent for a certain amount of time after birth o May be born deaf, blind, etc.  

o Dogs, mice, cats, humans, etc.  

What are the 2 types of reproduction?

∙ Iteroparous – produce offspring more than once in their lives ∙ Semelparous – produce offspring only once and then die o The time required to reach maturity can vary widely

Define phenotypic plasticity.

∙ A difference in phenotype of genetically identical individual. The same  genotype may result in different phenotypes based on environmental  cues or interactions between other genes

Define polygamy and explain the 2 types.

∙ Polygamy – an individual having more than one mate.  

∙ Polygyny – 1 male and multiple females (most common) ∙ Polyandry – I female and multiple males (less common) What are the mating systems in plants?

∙ Autogamy – self-fertilization

∙ Outcrossing – cross pollination.  

Define monogamy and promiscuity.

∙ Monogamy – one mate for life

∙ Promiscuity – no bonding; multiple partners; more than one mate.  Explain intrasexual selection and intersexual selection. ∙ Intrasexual selection - male-to-male (or female-to-female) competition  for mates

o Males compete amongst themselves, winner gets the ladies in  the area or gets to choose the female it wants

∙ Intersexual selection – attraction to individuals of the opposite sex. What are the two modes of females choosing mates? ∙ Selection for display characteristics (Females choose mates based on  displays, coloring, songs, chirps, etc.  

∙ Selection based on availability of resources such as habitat or food What is the MacArthur and Wilson life history classification? ∙ R-strategies – short life, lots of offspring, no parental care required,  adapted to variable requirements, high population growth at low  population densities

∙ K-strategies – long lived, stable populations, adapted to more stable  environments, fewer offspring, maintain population growth even at  larger densities, population is close to carrying capacity

What is the Grime life history classification for plants? ∙ R → ruderal strategy – rapidly colonize disturbed sites; small, short lived species.  

∙ C → competition – in predictable habitats with lots of resources, favors  competition

∙ S → stress tolerant – tolerate low availability or resources

Chapter 11: Intraspecific Population  Regulation

What does exponential growth (J-curve) assume?

∙ Unlimited resources

At what point does exponential growth slow and the population  stabilize?

∙ Slows just before reaching carrying capacity.

What does linear growth represent?

∙ Simple changes in population sizes as resources are shrinking Define carrying capacity (K).

∙ The maximum sustainable population size for a given environment.  ∙ At carrying capacity resources generated = resources consumed What is logistic population growth (S-curve) show?

∙ growth related to K.  

∙ When population is low, growth is almost exponential

∙ When population nears K, growth slows/decreases

Name some density dependent factors.

∙ Predation, diseases, food resources

∙ Density dependent mortality and fecundity

∙ These factors are affect the population at different levels depending on the density of the population

Name density independent factors.

∙ These factors can affect the density of the population, but do not affect a population because of density

∙ Weather, temperature, precipitation, flooding, drought, etc What are the two types of competition?

∙ Intraspecific – between individuals of the same species

∙ Interspecific – between individuals of different species

What are the two responses to shortage of resources? ∙ Scramble competition – growth and reproduction are depressed for all  involved

∙ Contest competition – some thrive while others suffer. There is a  contest for the resources

What are the two types of contest competition?

∙ Exploitation – individuals are not directly interacting

o Ex. One group of zebras grazes a pasture and prevents others  from eating it.  

∙ Interference – individuals are directly interacting with one another and  preventing the other from accessing resources.  

o A lion guarding a watering hole from others.  

What is self-thinning?

∙ The combined effects of density-dependent morality and growth within  a population. Very common in plants.  

What are the results of increased crowding and social interactions? ∙ Stress and aggression in the individuals

∙ Causes release of hormones that curb growth reproduction and delays  sexual activity; can lower immune system activity

∙ In some species it will lower birth rates and infant survival rates What is home range?

∙ The area used by an animal during the year (varies among and within  species)

What Is territory?

∙ Part of the home range that is defended.  

∙ Territoriality is a density dependent factor which shows when densities  are high.  

What is the Allee effect?

∙ At a low population size, birth rates decline or mortality rates increase ∙ Below the minimum population density, population growth is negative ∙ Higher population densities show more stability

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