BIO 200 Exam 1 9/11/2026-9/25/2026

What is the checklist for something being alive?

• Made up of cells

• cells replicate

• cells process and pass on information

• changing in response to their environment

• acquire and use energy

First Law of thermodynamics:

Energy is not created or destroyed. it is transferred by making or breaking chemical bonds, producing chemical gradients, and work from movement.

2nd law of thermodynamics

Every time energy is transformed, a portion becomes less usable. It is usually lost as heat. All energy transfers are inefficient. All living things must constantly transform energy to stay alive.

Biotic factors

Living organisms that affect the environment

Abiotic factors

all non-living components of the environment

Biotic and abiotic components all _____ in a typical ____.

cycle, ecosystem

Abiotic components _____.

cycle. This includes nutrients.

Gross primary productivity GPP

Total chemical energy produced in a given area over a time

Net Primary Productivity NPP

Chemical energy is used for growth and reproduction. Energy is stored inside the organism's cells.

Trophic level

The feeding level describes populations that have similar food sources.

Food chains

A directive that maps out where energy is transferred between organisms.

~__% is typically the amount of NPP that is transfered between levels.

10%

Decomposers are important because…

Without decomposers, nutrients would be locked up in detritus, halting productivity.

Detritus

Dead organic matter within the soil.

Ecosystem productivity depends on the recycling of matter through___ ____.

Nutrient cycles.

Nutrient cycles normally operate in ___, and ___ to that balance can destablize entire ecosystems.

equilibrium

disruptions

Normally, there is a balance between ___ fixation and ___.

carbon

respiration

Reasons why water is essential to life.

• Help define the environment we live in
• Chemical reactions take place in water
• Results in the formation of cellular structures and tissues

Water is a polar molecule that makes ____ bonds with itself and othe rpolar molecules.

hydrogen

___ of water molecules determins its physical characterisitcs.

Interactions

properties of water help form ___.

ecosystems

The sun is important because…

• allows for photosynthesis
• provides energy for primary producers
• decreases in producers will lead to significant losses at higher trophic levels
• disrupts the water cycle - no evaporation

Ecology

the study of how organisms interact with their environment

Populations are described by their ___ and ___.

distribution and abundance

Populations can optimize their ____ or _____.

survival and fecundity

fitness trader-off

Species can put energy into either survival or fecundity.

Fitness

refers to the ability of a population to survive and repoduce in a given environment.

Survivorship curves: Type I, II, and III

Type I: Human longevity until old age and then death Type II: Same probability of dying each year Type III: High death rate at the beginning, but large number of offsprings at the start.

Life history

describes how individuals allocate resources for growth, reproduction, and survivorship.

Determining population growth

r= b - d

b = births/ population

d= deaths/ population

for any population with a positive r, the growth is ___

exponential

Density-dependent factors

limit population sixe by alter birth and death rates

predation ___ as prey population increases

increases

Carrying capacity

The maximum number of individuals that can be supported in a population over a sustained period.

Density -independent factors

Also affect population growth and are mainly abiotic. This can include natural disasters that disregard population size.

Intrinsic growth rate

Growth rate per individual under ideal conditions. All populations grow slower than their intrinsic growth rate.

Logistic growth equation

Population grows exponentially, and the growth rate decreases as you approach carrying capacity.

Competition occurs when individuals use the sam____.

resources.

intraspecific competition

Competition between individuals of the same species.

Interspecific

Competition between two different species

Direct Competition

competition between species for resources that they directly fight over.

Indirect competition

Competition between species because they share the same resources.

Niche

Range of resources a species needs for survival Range of conditions a species can tolerate

Niches are multidimensional and can include:

food supply

temperature

terrain nesting sites

nutrients and warter

Competitive exclusion principle

two species that occupy the same niche cannot coexist

What happens if there is an overlap of conditions for more than one species?

One species will come out on top and another will loose.

Fundamental niche

possible range of resources that could be utilized

Realized niche

actual range of resources that could be utilized due to competition.

Competition causes fitness loss for all parties but the effects are ___.

unequal - one species will lose

Niche differentiation

When species that overlap in the same required resources shift away from shared resources.

Community Dynamics: Disturbance

A strong, short-lived event that changes the distribution of living and non-living resources.

Succession

Species repopulate after disturbance, and some species with specific life-history traits have greater success.

Primary succession

barren rock -> Soil

Secondary Succession

Organisms wiped out -> fertile soil remains

Resistance

quantity that remains after disturbance

resilience

how fast a species recovers

Characteristics that define community structure:

Total number of species

relative abundance and distribution of each species

sum interaction of all species

physical characteristics of a community

Specie richness

Number of different species in a community

Species diversity

Number of different species and their relative abundance

Keystone species

Have a greater impact on the overall diversity of a community

Trophic Cascades

Caused by the loss of a keystone species, changing one trophic level has ripple effect throughout the food web.

Top-down influence

Predator limits prey population

Bottom-up influence

Resource limitation propagating upward through trophic levels

Natural Selection occurs when individuals with certain _____ traits produce more offspring than individuals with that trait.

heritable

Transitional features

A trait observed in a fossil that is an intermediate form found in descendants.

Vestigial traits

reduced or undeveloped structures with little to no functions

Homology

is a similarity arising from common ancestry

Structural homology

similarity in bone structure of species

Developmental Homology

Similarity in embryo development

Genetic Homology

Similarity in the genetic sequence of species.

Fitness measures ___.

how many fertile offspring an individual produces

Adaptations are traits that ___ and individual's ___ in a particular environment.

increases

fitness

Species will keep adapting to each other through ____.

Coevolution

Natural selection does not change ___.

individual

Natural Selection is not ___ oriented.

goal

Natural selection does not lead to ___.

Perfection

Adaptive radiation

occurs when a single linage produces many descendant species with a wide range of adapative forms

Extrinsic factors

ecological opportunity. Lack of competition allows species to move into a vacant niche.

Intrinsic factors

Morphological, physiological, or behavior adaptations

Cambrian Explosion

a rapid adaptive radiation that seeded the species richness we observed today.

Monophyletic

A position on a tree. An ancestor and all its descendants. Defined by a shared derived character.

Paraphyletic

An ancestor, but not all of its descendants

Po9lyphyletic

It does not include the ancestor from which the trait came.

Morphospecies Concept

Differences in obersable charateristics like size, shape, features

Phylogenetic Species Concepts

Considers evolutionary history and genetic information

Gene Flow

is the movement of traits between populations

Genetic isolation

barrier to gene flow

Genetic divergence

isolated populations evolve independently

Allopatric speciation

Occurs when populations are geographically separated.