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64 Cards in this Set
- Front
- Back
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What is evolution? |
Evolution is Gradual Change. It is the most important concept in all of biology. |
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Where do current species (today's animals) come from? |
They are descendants of ancestral species. |
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What is the descendant theory created by Charles Darwin called? |
Descent with modification. |
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If individuals do not evolve, then what things do evolve? |
Populations evolve. |
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What does natural selection act on? |
Natural selection acts on individuals. |
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How do populations evolve? |
Populations evolve through inheritable changes in genetic material. |
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Are alleles advantageous or disadvantageous? |
TRICK QUESTION! They can be both, depending on the situation (environmental differences, mutational differences, etc). |
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How do alleles relate to species? |
In order to acquire a new species, you must generate new alleles. |
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Where do new alleles come from? |
Mutations in gametes and gene duplications in cells that produce gametes. |
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What are alleles? |
Alternative versions of a gene. |
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What is survival largely determined by? |
CHANCE! Survival is largely determined by chance. |
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What is another factor in the survival of an organism? |
Sexual selection.
This means that the characteristics important for survival aren't necessarily good when you want to secure a mate. |
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What do males and females look for with sexual selection? |
Males: Youth; Females: Resources. |
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What drives the sexual selection system? |
Female Choice. They invest in eggs, therefore they have huge amounts to lose. |
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What is microevolution? |
Microevolution is changing allele frequencies within a population but not producing a new species. |
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What is a species? |
A species is a population of animals which can potentially or actually interbreed and produce fertile individuals, but not with the members of another population. |
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What are four different ways that microevolutionary chance can happen? |
1.Chance Events(Genetic Drift and neutral selection) 2. Gene Flow 3. Mutation 4. Natural selection |
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What are two different kinds of effects caused by Chance Events? |
Founder Effect- a few individuals begin a new population. (when a population is founded by a small number of individuals, the frequency of alleles will be different than that of the larger, original population)
Bottleneck Effect- occurs when a population size is radically reduced. (surviving population has diff. allele frequencies than the original population) |
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What is Gene Flow due to? |
Gene Flow is due to immigration and emigration. |
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What are the three types of Mutations? |
Silent= no effect on functioning of gene product, the genetic code is redundant Mis-sense= meaning of the codon has changed, specifies a very different amino acid, alters the functioning of the protein Nonsense= codon changes meaning and can become a stop codon, creating a truncated protein. *severity varies-near beginning of protein, completely useless, near the end, only slightly truncated, may be fairly functional* |
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What is Natural Selection? |
The differential reproductive success of individual organisms. |
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Does Natural Selection have a purpose? |
NOPE! There is no purpose or goal and it is not directed towards the survival of the species. |
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What are the requirements for evolution to occur? |
1)Variation exists 2)Differences can be inherited 3)Different environments have different effects on different phenotypes. 4)Genotypes which produce the favoured phenotypes will be selected for by the environment. |
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What are different modes of Natural Selection? |
Stabilizing- discriminates against extremes Directional- discriminated against one extreme Disruptive- discriminates against the mean (opposite of stabilizing) *provides the possibility for no 'in between' individuals, and the mode of natural selection can lead to evolution of a new species* |
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What is Microevolution? |
Microevolution is the change in allele frequencies in a population. |
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What is Macroevolution? |
Macroevolution is the production of a new species. |
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What is Allopatric speciation? |
Allopatric speciation is when a population forms a new species while geographically isolated (separated) from its parent population. |
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What is Sympatric Speciation? |
Sympatric speciation is when a subset of a population forms a new species without geographic separation.
*This can result when new ecological niches form |
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What Convergent Evolution? |
Convergent Evolution is when two independent species evolve similar adaptations (similar traits, behaviours, etc) *can occur completely independently of each other (due to environment *cannot be the same species, leaving to analogous characters. |
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What does it mean to have Analogous characters? |
Analagous characters have the same function, differ in fundamental structure, and have different ancestry. |
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What does it mean to have Homologous characters? |
Homologous characters have the same or different function, they have similar fundamental structure, and have common ancestry. |
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What is Co-Evolution? |
Where the direction of evolution in one species is strongly influenced by evolutionary changed in another. *This often occurs when a species is dependent on another one (PREDATOR/PREY RELATIONSHIPS) |
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What are two rates of Evolution? |
1)Gradualism- over long periods of time, slow and gradual evolutionary change. 2)Punctuated Equilibrium- a new species appears abruptly in the fossil record, which is then followed by long periods of no evolutionary change. |
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What is the nervous system and what does it do? |
The nervous system is a signalling network. It mediates any responses that animals have to the environment to survive and reproduce. |
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What are neurons? |
Neurons are the basic functional cell of the nervous system. They are specialized for rapid electrical transmission of signals.
*They have a long cell body, dendrites, axon, and synapses. |
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What are dendrites? |
Dendrites are processes coming off the cell body that receive information |
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What is an axon? |
An axon has processes coming off the cell body that sends information |
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What are the three major types of neurons? |
Sensory, interneurons, and motor neurons.
*Sensory neurons are connected to interneurons by a synapse, and then an interneuron connected to a motor neuron is connected by a synapse as well |
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What are the three functions of the nervous system? |
Sensory input, information integration, and motor output. |
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What is in the Peripheral Nervous System (PNS)? |
Cranial nerves, spinal nerves, the afferent (sensory) and efferent (motor) nervous systems, and ganglia (that are outside of the CNS) |
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What is in the Central Nervous System (CNS)? |
The spinal cord and brain. |
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What are Schwann cells? |
Schwann cells form the myelin sheath, which insulates axons. *this makes signals more efficient by enhancing the speed at which signals move |
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How are signals transmitted (neurons)? |
Electrochemically.
Electrical- difference in charge between inside and outside of the cell Chemical- movement of chemical ions |
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What do gated ion channels do? |
Gated ion channels allow the in-flow of sodium ions and causes the membrane potential to become less negative (depolarization) |
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How do you create an action potential? |
When you reach the threshold, you create an action potential.
No threshold reached, nothing will happen. Threshold reaches, full blown action potential. Cell responds by pumping potassium ions out of the cell |
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What is an action potential? |
It is an all or nothing reaction. There is no partial reaction.
No threshold reached, nothing will happen. Threshold reaches, full blown action potential. Cell responds by pumping potassium ions out of the cell |
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What is a synapse? What are two kinds of synapses? |
A synapse is a neural junction.
1)Electrical- the electrical signal "jumps" are directly surrounded by gap junctions 2)Chemical- an electrical signal is transformed into a chemical one (transduction)
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What are synaptic vesicles? |
Synaptic vesicles contain the neurotransmitter.
*They are induced by calcium ions to travel to the end of an axon, fuse with the membrane, and enter a synapse. The neurotransmitter binds to a sodium ion channel on the next cell, producing a new action potential. *ensures that action potentials can only travel ONE WAY |
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What is Sensation? |
Sensation is the brain's awareness of some sort of bodily stimulation, first detected by the sense organs. |
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What is Perception? |
Perception is the brain's organization and interpretation of sensory information.
*how we view sensations |
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What are five functions of sensory receptors? |
1)Reception- receive from the outside (absorb energy from outside stimulus) 2)Transduction- conversion of stimulus energy into the electrochemical energy of action potentials and synapses 3)Amplification- if the stimulus is too weak to be carried by the nervous system 4)Transmission- action potentials 5)Integration |
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What are five types of receptors? |
1)Mechanoreceptors- mechanical stimulus (ears) 2)Chemoreceptors- chemical stimlus (taste buds) 3)Electromagnetic- electromagnetic radiation (eyes) 4)Thermoreceptors- temperature stimulus (skin) 5)Pain receptors- rather complicated |
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What is the acoustic sensory system? |
The acoustic sensory system is the detection of sound. |
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What does hearing involve? |
Hearing involves the stimulation of mechanoreceptors. This is waves (sound pressure waves) |
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What are two elements of sound and what do they determine? |
Two elements of sound are amplitude (intensity, volume) and wavelength (pitch) |
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What are the parts of the ear and what do they do? |
1)Tympanic membrane- "ear drum", it receives sound vibrations from the environment and transports them to the malleus. 2)Malleus, Incus, Stapes- bones that vibrate 3)Oval window- attached to the stapes, has a similar membrane to the tympanic membrane 4)Semicircular canals- are for balance, and are separate from hearing 5)Cochlea- where hearing occurs 6)Basilar membrane- where the mechanical receptors are in the ear |
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What are the steps of hearing? |
1)outer ear directs sound to external auditory canal 2)sound strikes tympanic membrane causing it to vibrate 3)vibrations are transmitted from malleus to incus to stapes 4)stapes moves the membrane of the oval window 5)causes stimulation of mechanoreceptors on the basilar membrane 6)sound waves exit out the round window |
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How is animal movement accomplished? |
All movements that we accomplish occur through the use of muscles. |
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What are muscles? |
Muscles are protein strands that move across each other called microfilaments. |
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How can muscles function? |
Muscles can function only if they have something to work against. These come in antagonistic pairs, meaning that they are pairs that work against each other. |
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What do muscle fibres consist of? |
Muscle fibres consist of myofibrils which are composed of two myofilaments- actin (thin) and myosin (thick) |
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How are myofibrils arranged? |
Myofibrils are arranged longitudinally |
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What is the sarcomere? |
The sarcomere is an arrangement of thick and thin filaments sandwiched between two Z-discs. |
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What is the sarcomere composed of? |
1)Z-line- entire length of a sarcomere, it separates one sarcomere from the next 2)I-band- lighter areas which contain thin filaments, but no thick filaments 3)A-band- middle area of the sarcomere where thick and thin filaments are found 4)H-zone- area of only thick filaments |
