Energy is acquired by living things in three ways: photosynthesis, chemosynthesis, and the consumption and digestion of otherliving or previously living organisms by heterotrophs
Energy is highest at the producer levels of food webs and is passed on to consumers above on the food web.
There are three broad categories of ecosystems based on their general environment: freshwater, ocean water,and terrestrial.
All ecosystems are different but there are categories that define what type of organisms might be found there based on things like the amount of water needed to survive.
Species dispersion patterns(or distribution patterns) show the spatial relationship between members of apopulation within a habitat at a particular point in time.
Sometimes humans move species and disrupt the natural order of species dispersion patterns.
population density, thenumber of individuals within a specific area or volume. Population size and density are the two maincharacteristics used to describe and understand populations.
population consists of the particular species that exist and how closely related they are. They are studied and graphed
These defenses may bemechanical, chemical, physical, or behavioral
Many different ways for species to defend themselves. Physical could be protection with thorns or something on the outside of the body. Chemical could mean the species can camouflage and hide from danger. Behavioral may mean they fight back or flee from the sign of danger.
constantly adapting to their environment to survive.
Terrestrial biomesare based on land, whileaquatic biomesinclude both ocean and freshwater biomes.
based on precipitation
abiotic factors
these factors can cause the organisms in the environment to change with them.
morphological, physiological, and behavioral.
The three types of adaptations by an organism
This cluster of genes isresponsible for determining the general body plan, such as the number of body segments of an animal, the number andplacement of appendages, and animal head-tail directionality.
Hox genes are responsible for putting the genes that are needed for the basic structure of an organism together.
Sensory structureshelp animals navigate their environment, detect food sources (and avoid becoming a food source for otheranimals!).
Every animal has a different sensory structures to help them survive. Smell can help you detect danger or smell a food source. Good hearing can help you to identify where danger is and how close it is. Some animals have better eye sight or can see better in the dark than the light. It is all to the animal's advantage.
Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions,respond to stimuli, and cope with environmental stresses
There are a lot of things going on to help an organism respond. Our bodies pump blood throughout our bodies and circulates oxygen that is needed to survive. Mechanisms for survival are built into every organism and differ based on what is needed for survival.
Organisms respond to diverse stimuli
Responses to stimuli is common in all organisms and is could be positive or negative.
Another type of evidence for evolution is the presence of structures in organisms that share the same basic form.
Similar structures is proof of a common ancestor between organisms.
Looking at every level of organization in living systems, biologists seethe signature of past and present evolution.
Organisms have adapted over time so much and we have proof in fossils and in nature
Thegood genes hypothesisstates that males develop these impressive ornaments to show off their efficient metabolism or theirability to fight disease. Females then choose males with the most impressive traits because it signals their genetic superiority,which they will then pass on to their offspring.
Females are selective with their mates and favor ones with more favorable traits.
frequency-dependent selection, favors phenotypes that are either common (positive frequency-dependent selection) or rare (negative frequency-dependent selection).
The most frequent is favored
Natural selection acts on entire organisms, not on an individual allelewithin the organism.
Determines fitness in organisms and populations
nown as thebottleneck effect, it results in suddenly wiping out a large portion of the genome (Figure 19.5). At once, thesurvivors' genetic structure becomes the entire population's genetic structure, which may be very different from the pre-disasterpopulation
Bottleneck effect
Heritabilityis the fraction of phenotype variation that we can attribute to genetic differences, or genetic variance, amongindividuals in a population. The greater the heritability of a population’s phenotypic variation, the more susceptible it is to theevolutionary forces that act on heritable variation.
More dominant traits are usually the ones that are used the most and get passed on to offspring.
The allele frequency within a given population can change depending on environmental factors; therefore, certain alleles becomemore widespread than others during the natural selection process
The genetic makeup of a population depends on the environment it lives in and how it has adapted to survive.
Many types of diverging characters may affect thereproductive isolation
Environmental factors have an effect on reproduction and can effect characteristics of the species when adapting to their specific environment.
Many species are similar enough that hybrid offspring are possibleand may often occur in nature, but for the majority of species this rule generally holds. The presence in nature of hybridsbetween similar species suggests that they may have descended from a single interbreeding species, and the speciation processmay not yet be completed.
hybrid offspring is usually not viable and cannot reproduce on their own but is possible for creating new species
In other cases, individuals may appear similar although they are not members of the same species.
Categorizing organisms into species can be difficult when so many are similar and new species are always being discovered or created.
lades can vary in size depending on which branch point one references
Clades separate groups of species that are closely related
If a plant contains a compound that is effective intreating cancer, scientists might want to examine all of the compounds for other useful drugs
Using natural medicines to treat illnesses is a great way to use our environment to our advantage.
In general, organisms that share similar physical features and genomes are more closely related than those that do not
In a genotypic tree, two species with the most homologies structures will share the same branch and will be the most closely related to each other.
To a prokaryote, humans may be just another housing opportunity. Unfortunately, the tenancy of some species can have harmfuleffects and cause disease
Bacteria seeks human bodies as an environment along with other species. But some bacteria can be very harmful to the human body and can cause diseases. The bacteria is feeding on the human body and using it for nutrients and shelter while the body is infected and sick.
Reproduction in prokaryotes isasexualand usually takes place by binary fission. (Recall that the DNA of a prokaryote is a single,circular chromosome.) Prokaryotes do not undergo mitosis; instead, the chromosome is replicated and the two resulting copiesseparate from one another, due to the growth of the cell.
asexual reproduction does not require much contact to reproduce and does not need sexual beings to reproduce. An example of this is seeds spreading and planting new life.
Thecell wallfunctions as aprotective layer, and it is responsible for the organism’s shape.
Cell walls are present in plants and prokaryotes
In alternation of generations, the multicellular haploid form, known as a gametophyte, is followed in the developmentalsequence by a multicellular diploid form, the sporophyte.
haploid: reproductive cells diploid: non-vascular plants
Some elements—such asnitrogen and phosphorus—are required in large quantities by biological systems, and yet are not abundant in the environment.The action of fungi releases these elements from decaying matter, making them available to other living organisms.
Decomposed organisms provide necessary elements for other living organisms through fungi. Every organism plays a role in helping others to survive. Some things we would never think of as so important.
he roots of the plant connect with theunderground parts of the fungus, which formmycorrhizae. Through mycorrhizae, the fungus and plantexchange nutrients and water, greatly aiding the survival of both species. Alternatively, lichens are anassociation between a fungus and its photosynthetic partner (usually an alga)
This is an example of mutualism: two species relying on each other for aspects of survival. They mutually benefit from helping one another.