Untitled Flashcard Set
Chapter 32: Overview of Animal Diversity
Key Characteristics which allow animals to become efficient consumers:
Heterotrophic measures → animals can always eat eachother.
Development of Tissues → groups of tissues with a specialized function.
Development of Digestive System → allows for the breakdown of food into absorbable units, promoting nutrient acquisition and energy efficiency.
Development of advanced specialized cells → detection, speed, movement.
32.1: animals are multicellular, heterotrophic, eukaryotes. which develop from embryonic layers.
Nutritional Mode → consumption of organic material is dependent on the animal instead of generation by breakdown of inorganic substances.
Defined Cell structure and Specialization → unlike our cell wall-bearing eukaryotes, animals have flexible cell functionality/membrane and collagen structures which organize and support cells.
Tissues → groups of similar cells which act as an functional unit.
Reproduction and Development → Most animals reproduce sexually w/ diploid stage dominating life cycle, where embryonic formation occurs and eventual development.
Sperm and egg cells are produced by meiotic division (scrambling of genetic material), ensuring genetic diversity among offspring.
Diploid Zygote becomes present in majority of animal species after sperm fertilizes larger non-motile egg.
Cleavage → the rapid cell division of the zygote that occurs after fertilization, leading to the formation of a multicellular embryo.
Blastula → a hollow ball of cells that forms during the early stages of embryonic development, typically following cleavage, and serves as a precursor to the formation of the gastrula.
Gastrulation → the process during which the blastula reorganizes into a three-layered structure known as the gastrula, establishing the primary germ layers: ectoderm, mesoderm, and endoderm.
Metamorphosis instead of “development” → Some animals undergo metamorphosis, a transformative process that akin to development that lacks sexual maturity.
Homeoboxes → a group of genes that provide important positional information during embryonic development, influencing the body plan and segment identity in organisms.
C 32.2: Animals live long
Multicellularity requires evolution of new ways for cells to adhere and signal to one another.
Cadherin attachment proteins found in M. brevicollis are very similar to cadherin-like protein of choanflagellates. It appears simple rearrangement of novel proteins encourage it.
Neoproterozoic Era (1 Billion-540 million)
Most data indicates fossils of origin that are older, but we accept macroscopic data of animals dating to 560 million years back.
Ediacaran biota → Early smaller group of mostly soft-bodied multicellular eukaryotes.
Some Edicaran biota fossils resemble animals, some as molluscs, some sponges or cnidarians and some a mix.
Early predation likely begun around this time. Cloudina, an small animal of this era, shows attacks on their shells where predators may of buried into them.
Paleozoic Era (541-252 Million Years Ago)
Cambrian explosion → the rapid diversification of life forms that occurred approximately 530 million years ago.
Roughly half of the oldest fossils lie within animal phyla and exhibit large bodies with hard, mineralized skeletons.
Cambrian fossils are presumed to be extant species of the animal phyla.
Bilaterian rise → enormous clade whose members exhibit bilateral symmetry, which allows for a distinct head and tail region, facilitating more efficient movement and organization of the nervous system.
Ending of the Era is marked by vanishing Ediacaran Biota-like organisms and larger organisms which represent a growing predator-prey dynamic.
Atmospheric Oxygen theory → hypothesis suggesting that the increase in atmospheric oxygen levels during the Cambrian period was a critical factor in the diversification and evolution of animal life, allowing for larger body sizes and more complex metabolic processes.
Small genetic changes of Hox
Followed by and Impact
Followed by Ordovician, Silurian and Devonian periods which marked increased diversity followed by episodes of mass extinction.
Vertebrates (fishes) emerged as top predators of the marine food web.
Arthropods made impact around 450 million years ago; they were first animals to adapt to terrestrial habitats.
Vertebrates would continue to colonize land and diversify into amphibians and amniotes.
Mesozoic Era (252-66 Million Years Ago)
Dinosaurs, angiosperm diversification and animal phyla.
Established animal phyla which begun spreading into different habits.
Coral reefs begun to form, allowing diversification of habitats.
Some reptiles returned to marine environments, giving rise to groups such as ichthyosaurs and plesiosaurs.
Descent with modification on some tetrapods led to emergence of flight and wings.
Large and small dinosaurs emerged and nocturnal species adapted to new niches, showcasing a remarkable variety of forms and behaviors in response to changing environmental conditions.
Cenzoic Era
Era mostly marked by mass extinctions of both terrestrial and marine animals.
Nonflying dinosaurs and marine reptiles particularly.
Large mammalian herbivores and predators.
Global cooling required adaptations among various species as many struggled to survive in significantly altered habitats and ecosystems.
Vacated spots allowed for new species to emerge and fill ecological niches, leading to increased biodiversity in ecosystems that had faced significant challenge.
C. 32.3: Animals characterization by body plan.
Body plan → particular set of morphological and developmental traits that get integrated the functionality of the organism.
Symmetry → Basic feature of animal bodies is their symmetry expressed as: radial or bilateral or absence.
Radial Symmetry → body parts arranged around a central single main axis.
Sessile or planktonic by nature.
Bilateral Symmetry → body has a right and left side that are mirror images of each other, allowing for better movement and the development of a distinct head region.
Active and have sensory equipment.
Tissues → Germs layers: Ectoderm and endoderm with questionable mesoderm.
Ectoderm → germ layer covering surface of embryo; gives rise to outer covering and in some phyla, central nervous system.
Endoderm → innermost germ layer; lines pouch of gastrulation, digestive system and linings to other organs of liver and lungs.
Mesoderm → middle germ layer absent in some animal groups; it develops into the muscles, skeletal system, circulatory system, and connective tissues, playing a crucial role in organ formation.
Body Cavities → fluid- or air-filled space; animals have one usually between endoderm and ectoderm.
Coelom → Typical in triploblasts, it is a cavity body formed from mesoderm that allows adherence and internal structure to organs inside.
Contains fluids which cushions suspended organs.
Many animals contain a coelom.
Allows organs to grow and move independently.
Hemocoel → body cavity that forms between the mesoderm and endoderm.
Contains hemolymph, a fluid which functions in internal transport of nutrients and waste. It’s analogous to your blood.
Seen in round worms and other stuff.
Many animals have a hemocoel, which can act as primary body cavity.
Psuedocoelomates → used to have a true coelom but evolved to have a pseudocoelom, which provides structural support and space for internal organs, while still allowing for the movement of fluids.
Compact (no body cavity) → lack a true body cavity, although diploblastic.
Seen in planarians and flatter worms.
Don’t need enough space for organ expansion since they rely on diffusion for nutrient and waste exchange.
Protostome and Deuterostome Development
Two distinct development modes → protosomal and dueterostomal.
Cleavage
Spiral cleavage → animals with protostome development undergo spiral cleavage typically. Planes of cell division align on vertical axis and result in a coiled arrangement of cells, leading to a determinate growth pattern.
Determinate cleavage → each embryonic cell has a predetermined fate, meaning that the developmental trajectory of each cell is fixed early on, which influences the overall structure and function of the mature organism.
Radial cleavage → Animals with deuterostome development, where planes of cell division are oriented parallel or perpendicular to the vertical axis, resulting in a more symmetrical arrangement of cells. This process allows for indeterminate growth, meaning that the fate of each cell can change throughout early development, providing more flexibility in forming various structures.
Coelom Formation
Archenteron → developing embryo’s digestive tube forms as a blind pouch.
Protostome development → causes solid masses of mesoderm to split and form the coelom.
Deuterostome development → mesoderm buds from wall of archenteron, and forms it’s own cavity into a coelom.
Blastopore Fate
Protostome (first protos, stoma mouth) → mouth generally forms from first opening on blastopore, and is characteristic for it.
Deuterostome (dueteros second) → mouth derived from secondary opening and blastopore usually forms the anus.
32.4 Views of animal phylogeny continue to be shaped.
All animals share a common ancestor → current evidence indicates all animals are monophyletic, forming clade Metazoa.
Sponges are sister group to all other animals → Sponges (phylum Porifera) are basal animals, having diverged from all other animals early in the history.
Eumetazoa is a clade of animals with issues → all animals except for sponges and a few others belong to a clade of “Eumetazoan” true animals.
Most animal phyla belong to clade Bilateria → they exhibit bilateral symmetry, which is characterized by a single plane of symmetry that divides the body into mirrored halves.
There are three major clades of bilaterian animals → the Lophotrochozoa, Ecdysozoa, and Deuterostomia, each distinguished by unique developmental and morphological traits. With exception of Chordata, they all lack a backbone.
Lophotrochozoa → two different features observed in the lophotrochozoan clade:
Lophophore → a crown of ciliated tentacles used for feeding and respiration, often found in organisms such as bryozoans and brachiopods.
Trocophore larva → a distinctive, free-swimming larval stage that is characteristic of many lophotrochozoans, playing a crucial role in their life cycle and dispersal.
Clade Ecdysozoa → group characterized by secretion of external skeletons or molding.
Animal grows → old exoskleton → bigger exoskeleton.
Chapter 40: Basic principles of animal form and function
Natural selection determines animal size and shape based on environmental factors, predation pressures, and available resources.
An seal needs less bumps than a porcupine, as a streamlined body is more advantageous for swimming and escaping predators in aquatic environments.
Physical laws also influence animal body plans with regard to maximum size.
Thicker skeletons and muscles required for larger body dimensions.
Metabolic needs and mobility can become impacted dependent on size.
Exchange w/ environment
Animals must exchange nutrients, waste products, and gases with their environment to maintain homeostasis.
Substances dissolve in aqueous solution, and diffuse across plasma membranes.
Rate of exchange is proportional to membrane surface area involved in exchange.
You want maximal ratio of outer surface area to total volume.
Many animals with simple internal organization have body plans which allow for direct exchange between their cells and the environment, maximizing their surface area relative to volume.
Some body plans prefer to maximize exposure by flatter shapes, such as those seen in flatworms, which enhances their ability to absorb nutrients and gases efficiently through diffusion.
Adaptions are important, they have enabled exchange despite specialized surfaces such as folding.
Complex systems promote greater efficiency in resource exchange through the development of specialized structures, like lungs and gills, which enhance the surface area available for transfer without compromising the overall volume of the organism.
Hierchical Organization of Body Plans
Four main types of animal tissues: epithelial, connective, muscle, and nervous.
Epithelial Tissue → covers the outside of the body, lines organs and cavities, provides protection against pathogens and fluid loss and interacts with the environment.
Stratified squamous epithelium → multilayered and regenerates quickly. This type of epithelium is found in areas subject to abrasion, such as the skin and the lining of the mouth.
Cuboidal epithelium → single layer of cube-shaped cells, which is involved in secretion and absorption. This type of epithelium can be found in glands and the kidney tubules.
Simple columnar epithelium → large, brick-shaped cells of simple columnar epithelia that are also involved in absorption and secretion. This type of epithelium is commonly found in the lining of the gastrointestinal tract, where it aids in digestion and nutrient absorption.
Simple squamous epithelium → a single layer of flat cells that facilitates diffusion and filtration processes. This type of epithelium is typically found in areas such as the alveoli of the lungs and the lining of blood vessels.
Psuedostratified columnar epithelium → characterized by varying cell heights and a single layer of cells that appears multi-layered; this type of epithelium is often found in the respiratory tract and is involved in secretion and movement of mucus.
Concept 40.2: Feedback control maintains the internal environments in many animals.
Regulator → animal that maintains stable internal conditions (homeostasis) by utilizing various mechanisms to control processes such as temperature, pH, and fluid balance.
Conformer → an animal that adjusts its internal conditions to match the external environment, often relying on behavioral adaptations to maintain homeostasis in fluctuating conditions.
There are preferences and non-specific ones.
Feedback Control
Set point → a specific value or range of values that the body aims to maintain for a physiological variable.
Stimulus → a change in the environment that disrupts the set point, prompting the body to initiate responses to restore balance.
Response → the actions or reactions of the body to a stimulus, aimed at returning the physiological variable back to the established set point.
Negative feedback (gas pedal) → control mechanism that “damps” its original stimulus.
Positive feedback (snowball downhill) → a control mechanism that amplifies the original stimulus, leading to an increasingly stronger response until a desired outcome is achieved.
Alterations in Homeostasis
Regulated changes → planned changes in normal homeostatic functions that occur in response to specific environmental or internal changes, ensuring the body maintains equilibrium despite fluctuations.
Cyclic cycle.
Circadian Rhythm → the natural, internal processes that regulate the sleep-wake cycle and other bodily functions, typically repeating every 24 hours.
It’s intrinsic → lack of influence doesn’t cause harm.
Influenced by melatonin release and exposure to light.
Acclimatization → animal’s physiological adjudgment to changes in its external environment.
Elk move up mountains → hypoxemia → increased respiration.
C 40.3: Homeostatic processes for themoregulation
Thermoregulation → animals maintain body temp within specific range.
Endothermic → animals produce heat by metabolism.
cooling procedures
Ectothermic → animals gain heat by environment.
lack cooling mechanisms
behavior first and less food.
more variance allowed.
Insulation → reduces flow of heat between body and environment.
Found at body surface (hair and feathers) and in layers of adipose tissue.
Some oils can be secrected.
Radiation → emission of electromagnetic waves from a surface due to its temperature, which is critical in managing thermal conditions and preventing overheating.
Evaporation → removal of heat from surface of liquid through the transition of molecules from the liquid phase to the vapor phase.
Convection → transfer of heat by movement of air or liquid past a surface.
Conduction → physical touch
Circulatory Adaptions
Thermogenesis by endotherms → the process of generating body heat through metabolic means such as muscle activity or shivering.
Chemical reactions such warmed-up “flight” motors.
Non-shivering thermogenesis → Endocrine signals can be released to encourage mitochondria to let off heat instead of building ATP for currency later.
Brown fat thermogenesis → specialized white adipose tissue, looking brown due to it’s mitochondrial content, and is primarily involved in non-shivering thermogenesis, utilizing fatty acids to produce heat instead of storing energy.
Acclimatization in Thermoregulation
Ectotherms
Within ectotherms, adjustments are usually at cellular level.
Ectotherms may release variants of enzymes or proportions of saturated to unsaturated lipid content may change.
Some can even produce “antifreeze” proteins, withstanding a full degree below freezing point.
Endotherms
Acclimatation can result in a thicker coat of fur or increased fat storage, enabling these organisms to retain heat and survive in colder environments.
Pyrogens, or heat-producing processes, allow endotherms to maintain a stable internal temperature regardless of external conditions.
Hypothalamus and Fevers
Hypothalamus is responsible for circadian clock, hormone secretion and body temperature.
Body temp increases → sensed → hypothalamus response → vasodilation, filled capillaries and sweat gland excretion increase → body temp declines.
Body temp decreases or mediator → hypothalamic response → vasoconstriction, increased metabolic rates and shivering.
Behavioral fever → the phenomenon where an organism actively seeks to raise its body temperature in response to infection, enhancing immune function and promoting the healing process.
C 40.4: Energy requirements
Basal Metabolic Rate (BMR) → minimum metabolic rate of a nongrowing endotherm that is at rest, has an empty stomach, and is not experiencing stress.
Temperature measured at is “comfortable”
Standard Metabolic Rate (SMR) → the metabolic rate of a resting, fasting ectotherm at a specific temperature.
BMR for adult males is 1600-1800 and for adult females 1300-1500 a day. This is roughly a day energy use of a 75-watt lightbulb.
Inverse relationship between body size and energy demand.
Due to higher metabolic need due to lower specialized tissue, smaller ectothermic animals generally have a higher standard metabolic rate per unit body mass compared to larger ones.
Most terrestrial animals average daily rate of energy consumption 2-4 times BMR/SMR while humans have average daily rate of energy consumption of roughly 1.5x BMR, indicating a sedentary lifestyle.
Torpor and Energy Conservation
Torpor → Major adaption that enables animals to save energy in state of difficult conditions. Their metabolic rates decrease while their activity decreases as well.
Torpor can be daily for birds and smaller animals, while all endotherms may do torpor every day it’s far less significant.
Hibernation → long-term torpor that is an adaption to winter cold and food scarcity.
Some can enter a supercooled (unfrozen but below 32 degrees) state.
Metabolic rates can be almost 20 times lower than normal levels.
Weeks of hibernation interrupted by brief periods of arousal can help animals maintain energy balance and manage hydration.
Hypothalamic control of circadian clock seems to drop as well.
Estivation → a state of dormancy characterized by a slowing of metabolic processes in response to extreme heat and drought, allowing many animals to survive in conditions where water is scarce.
C 52.1
Latitudinal Variation in Sunlight Intensity → Earth’s curved shape causes latitudinal variation in intensity of sunlight.
Sun overheads at equinoxes or 0* while low light is present on the poles.
Sunlight most direct and intense in tropics ~23.5
Seasonality → Earth’s tilted axis of rotation and annual passage around the sun causes seasons, which causes increased/decreased temperatures and behaviors.
June solstice occurs when the North Pole is tilted closest to the sun, resulting in the longest day of the year for the Northern Hemisphere while the Southern Hemisphere experiences the shortest.
Bodies of Water → ocean currents influence climate along coasts by heating or cooling overlying air masses.
High specific heat allows water to absorb and store heat energy, moderating coastal temperatures and creating milder climates compared to inland areas.
Mountains act as regulators for this; cooled air from water moderates temperature before clumping (and becoming rain/snow) and subsequently falling on the windward side, while the leeward side often experiences a rain shadow effect, leading to drier conditions.
Also limit sunlight passing, allowing for cooler air temperatures and reduced evaporation rates, which can further influence local humidity and precipitation patterns.
Forests are darker in color than a desert, which makes them absorb more solar energy and reflect less. Although, the pick-up is lost in transpiration in forested areas.
Evaporative loss of water is much greater causing increased precipitation rates and reduce Earth’s surface temperature.
Less forests → more solar radiation and lower transpiration rates; plant death and surface warming w/ less rain.
Four major physical components of climate are temperature, precipitation, sunlight, and wind.
Climate and Interactions between Environment
The microclimate is a very fine, localized pattern in climatic conditions.
A local mountain can cause a shaded slope.
Climographs plots help plot annual mean temperature and precipitation in a region.
Dispersal → the movement of individuals or gametes away from their area of origin or of high population density.
Biotic Factors → the living components of an ecosystem that influence the distribution and abundance of organisms, such as competition, predation, and symbiosis.
Abiotic Factors → the non-living chemical and physical components of the environment that affect living organisms, including temperature, water, sunlight, soil, and nutrients.
Temperature, water and oxygen, salinity, sunlight, and rocks and soil.
Scope of Ecological Research
Organismal Ecology → Includes subdisciplines of physiological, evolutionary, and behavioral ecology, and is connected with how an organism interacts with its environment and other organisms.
Population Ecology → population is a group of individuals of the same species living in an area.
Community ecology → examines the group of populations in a different area.
Ecosystem ecology → focuses on the interactions between communities and their physical environment, emphasizing energy flow and nutrient cycling within ecosystems.
Landscape ecology → studies the interactions between spatial patterns and ecological processes across multiple ecosystems, integrating both biotic and abiotic components.