Bio Exam 3 Flashcards
Eukaryote
A member of the domain Eukarya; an organism whose cells contain a nucleus, numerous membrane-bound organelles, and an extensive cytoskeleton. May be unicellular or multicellular.
Multicellular
The state of being composed of many cells that adhere to each other and do not all express the same genes, resulting in some cells having specialized functions.
Endoderm
The innermost of the three basic cell layers (germ layers) in most animal embryos; gives rise to the digestive tract and organs that connect to it (liver, lungs, etc.). Compare with ectoderm and mesoderm.
Ectoderm
The outermost of the three basic cell layers (germ layers) in most animal embryos; gives rise to the outer covering and nervous system
Mesoderm
The middle of the three basic cell layers (germ layers) in most animal embryos; gives rise to muscles, bones, blood, and some internal organs (kidney, spleen, etc.)
Radial Symmetry
An animal body pattern that has at least two planes of symmetry. Typically, the body is in the form of a cylinder or disk, and the body parts radiate from a central hub.
Bilateral Symmetry
An animal body pattern in which one plane of symmetry divides the body into a left side and a right side. Typically, the body is long and narrow, with a distinct head end and tail end.
Cephalization
The formation in animals of a distinct anterior region (the head) where sense organs and a mouth are clustered.
Coelom (Body Cavity)
An internal, usually fluid-filled body cavity that is completely or partially lined with mesoderm
Segmentation
Division of the body or a part of it into a series of similar structures; exemplified by the body segments of insects, annelid worms, and vertebrates.
Diploblast
An animal whose body develops from two basic embryonic cell layers or tissues—ectoderm and endoderm
Triploblast
An animal whose body develops from three basic embryonic cell layers or tissues: ectoderm, mesoderm, and endoderm
Optimal Foraging Theory
The concept that animals forage in a way that maximizes the amount of usable energy they take in, given the costs of finding and ingesting their food and the risk of being eaten while they’re at it.
Fitness trade-offs
In evolutionary biology, an inescapable compromise
between two traits that cannot be optimized
simultaneously.
Ecology
The study of how organisms interact with each other and with their environment.
Sexual Selection
A type of natural selection that favors individuals with traits that increase their ability to obtain mates or choose good mates.
Monogamous
A type of mating system where one male mates with one female per breeding season, forming a pair bond
polygynous
A type of mating system where one male mates with two or more females (polygyny) or one female mates with more than one male (polyandry) during a breeding season
Intrasexual selection
A type of sexual selection driven by competition among members of one sex (usually male–male) for an opportunity to mate.
Intersexual selection
A type of sexual selection in which an individual of one sex choses a particular individual of the other sex for mating (often occurs through female choice).
Ethogram
a catalog or table of all the different kinds of behavior or activity observed in an animal.
Sexual Dimorphism
Any trait that differs between
males and females
Population Ecology
The study of how and why the number of individuals in a population changes over time and space.
life history
The sequence of events in an individual’s life from birth to reproduction to death, including how an individual allocates resources to growth, reproduction, and activities or structures that are related to survival.
Exponential growth
The accelerating increase in the size of a population that occurs when the per capita growth rate is constant and density independent
Logistics growth
The density-dependent decrease in growth rate as population size approaches the carrying capacity
Density dependent growth
Density-dependent growth is a process in population ecology where the growth rate of a population is regulated by the density of the population
Density independent growth
Density-independent growth refers to the growth of a population that is not affected by the density of individuals
carrying capacity
The maximum population size of a certain species that a given habitat can support over a sustained period of time
Finite rate of increase
The rate of increase of a population over a given period of time. Calculated as the ending population size divided by the starting population size
Per capita rate of increase / instantaneous rate of increase
Also called instantaneous rate of increase. The difference between the birth rate per individual and the death rate per individual
Community ecology
study of the organization and functioning of communities, which are assemblages of interacting populations of the species living within a particular area or habitat
Commensalism
relationship between two species of organisms in which one species benefits while the other is unaffected
Competition
In ecology, the interaction of two species or two individuals trying to use the same limited resource (e.g., water, food, living space). May occur between individuals of the same species (intraspecific competition) or different species (interspecific competition
Consumption
In ecology, the interaction between species in which one organism eats or absorbs nutrients from another. Includes predation, herbivory, and parasitism
Mutualism
A species relationship between two organisms (mutualists) that benefits both
Interspecific competition
Competition between members of different species for the same limited resource
Intraspecific competition
Competition between members of the same species for the same limited resource.
Niche
The range of resources that a species can use and the range of conditions that it can tolerate. More broadly, the role that a species plays in its ecosystem.
Niche Differentiation
The evolutionary change in resource use by competing species that occurs as the result of character displacement.
character displacement
The evolutionary tendency for the traits of similar species that occupy overlapping ranges to change in a way that reduces interspecific competition.
Fundamental niche
The total theoretical range of environmental conditions that a species can tolerate
Realized niche
The portion of the fundamental niche that a species actually occupies given limiting factors such as competition with other species
competitive exclusion principle
The principle that two species cannot coexist in the same ecological niche in the same area because one species will outcompete the other.
Coevolution
A pattern of evolution in which two interacting species reciprocally influence each other’s adaptations over time
Constitutive defenses
A defensive trait that is manifested even in the absence of a consumer (predator, herbivore, or parasite). Also called standing defense
Inducible defenses
A physical, chemical, or behavioral defensive trait that is manifested only in response to the presence of a consumer (predator, or herbivore, or parasite) or pathogen.
Richness
The number of species present in a given ecological community
Diversity
The variety and relative abundance of the species present in a given ecological community.
Shannon Index
The Shannon index is a measure of diversity in categorical data, especially in environmental science and ecology
Keystone species
A species that has an exceptionally large impact on the other species in its ecosystem relative to its abundance
Disturbance
In ecology, any strong, short-lived disruption to a community that changes the distribution of living and/or nonliving resources.
Succession
In ecology, the gradual colonization of a habitat after an environmental disturbance (e.g., fire, flood), usually by a series of species
Biodiversity
The diversity of life considered at three levels: genetic diversity; species diversity; and ecosystem diversity
Resilience
In community ecology, a measure of how quickly a community recovers following a disturbance.
Resistance
In community ecology, a measure of the extent to which a community remains unchanged in the face of a disturbance.
