Ecology and Evolution Concepts

Flashcards covering key concepts from ecology and evolution including diversity, species interactions, evolutionary processes, and experimental design.

Ecological Diversity

The variety of species and habitats in an ecosystem.

Community Composition

The species present within an ecological community and their relative abundances.

Species Interactions

The relationships between different species in an ecosystem, including competition, mutualism, commensalism, and predation.

Independent Variable

The variable that is manipulated in an experiment.

Dependent Variable

The variable that is observed or measured in an experiment.

Positive Control

A group in an experiment with a treatment expected to have a positive effect.

• Ex: Testing a medical screening device on patients who already known to have the disease

Negative Control

A group in an experiment expected to have no effect from the treatment.

Mutualism

An interaction where both species benefit (+/+).

Commensalism

An interaction where one species benefits, and the other is neither helped nor harmed (+/0).

Amensalism

An interaction where one species is harmed while the other is unaffected (-/0).

Interspecific Competition

Competition between individuals of different species.

Intraspecific Competition

Competition between individuals of the same species.

Evolution

Descent with modification; the change in heritable traits of biological populations over successive generations.

Natural Selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Species Richness

The number of different species represented in a given ecological community.

Species Evenness

The relative abundance of each species in an ecosystem.

Adaptive Evolution

Changes in the frequency of advantageous traits of a population over time due to natural selection.

Biogeography

The study of the distribution of species and ecosystems in geographic space and through geological time.

Shows how species evolved, why species live where they do, and how biodiversity has been affected by external factors

Dichotomous Key

A tool used for identification of organisms based on a series of choices between alternative traits.

Law of Succession

The concept that species change over time following a predictable sequence of species replacement after disturbances.

Homologous Structures

Anatomical features in different species that share a common ancestor.

Transitional Forms

Fossils or organisms that display characteristics intermediate between two or more groups.

• Ex: archaeopteryx has features of both birds and dinosaurs.

Artificial Selection

The process of selecting and breeding organisms for desired traits driven by human choice.

Vestigial Structures

Anatomical features that have lost most or all of their original function through evolution.

• Ex: appendix in humans

Molecular Homology

Similar DNA and protein sequences between different species, providing evidence for common ancestry.

Can be used to study relationships between species that are not closely related/ look similar.

Convergent Evolution

The process whereby unrelated species develop similar traits as a result of similar environmental pressures.

• Ex: Sharks and dolphins both have fins to swim in water but are unrelated

Biodiversity

The variety and variability of life forms, including the diversity within species, between species, and of ecosystems.

• genetic, species, and habitat are the three levels

Niche Partitioning

The process by which competing species (interspecific) reduce competition by using resources in different ways.

Principal of Competitive Exclusion

The principle that two species competing for the same limited resource cannot coexist.

Mean

The average value of a set of numbers.

Standard Deviation

A measure of how spread out the numbers in a data set are around the mean.

P-value

The probability value that indicates the strength of the evidence against the null hypothesis.

Interspecific

competitions between different species

Intraspecific

competition between the same species

Exploitation

indirect interaction between individuals (competitor consumes resources, whoever consumes more is the competition)

Interference

Direct interaction between individuals (competitors physically intimidate each other to scare off other from eating resources)

Underyielding

If competition affects one or both species, total yield may be lower in a mixture than in monoculture

• Interspecific competition

Underyielding

if competition affects one or both species, total yield may be lower in a mixture than in a monoculture

• Intraspecific competition

Theory of Limiting Similarity

Species that are too similar cannot coexist

Gender Dimorphism

Differences in appearance, behavior, or trait between females and males of the same species

Taxonomy

Scientific classification and naming organisms

King Paramecium Cares Only For Green Spirulina

King
Phylum (divisons)
Class
Order
Family
Genus
Species

• gets more specific as you go down

Phylogeny

Evolutionary history of a species or a group of species that can be put into a branched tree

Basal Taxon

The branch near the root of the tree that helps to understand evolutionary relationships within a clade

Sister Taxa

Species within a specific unit in an evolutionary tree, sharing an immediate ancestor

Nodes

Point of divergence where a single lineage split into two or more

Internal nodes help to show clade formations

Transitions

specific traits that are useful in distinguish differences between states of species that share ancestry

Unity

All organisms share common ancestry and fundamental molecular structures

Diversity of Life

Organisms still display vast morphological and functional variations that can be drive by evolution, natural selection, and genetic adaption over time despite there being a common ancestry/fundamental molecular structure shared between organisms

Allopatric Speciation

Populations are geographically separated and evolve independently of each other

Sympatric speciation

When populations become reproductively isolated within the same geographic area

Explain how museum cultures can let us see changes in biodiversity or biogeography and describe how this lets us infer past climate or habitat

Museums give a record of the past and present biodiversity allowing scientists to study changes in species diversity, morphology, and distribution
This lets us identify ecological factors that influence distribution of species. They can begin to understand patterns of dispersal, colonization, and extiniction

Explain Genetic Biodiversity

Variation of genes within and among populations of a single species.
Comes from mutations, genetic recombination, and other genetic processes that introduce new genetic variations into the population.
Overtime natural selection and other evolutionary processes will favor certain traits caused by the genetic variation for fitness and survival.

Explain Species Biodiversity

Variety of species in an ecosystem, region, or plant. Gives ecological stability, allowing ecosystems to resist disturbances, and keep their functions over time.
Creates species richness and evenness

Explain Habitat Biodiversity

Variety of ecosystem and habitats found in a region.
It supports adaptation and resilience of species and population in face of environmental change.
It provides different habitats and niches that support many species and help them survive.
Each has its own assemblage of species and ecological process

Importance of genetic diversity

Allows populations to adapt to changing environments. Diverse populations increase the chance for individuals to possess traits that’ll allow for survival and reproduction under changing conditions. 
Builds resistance to disease 
Allows for variation for natural selection to act on, making it a factor of evolution
Populations are more vulnerable to extinction from environmental changes without genetic diversity

What large factors can influence the range of a species

Climate, Habitat availability, dispersal availability, Competition/predation, Human Activities

How can human activity change biogeography (effect of invasive species)

Humans can act like an invasive species to other species with the space we take and the production we do (building, pollution, etc.) 

Introducing invasive species can have a negative impact on the ecosystem as a whole.
It can alter the composition of community and disrupt interaction between native species

Why do we use statistics in biology

To interpret complex data by separating true biological signals from random variation and measurement error 

• In the case of the deWit replacement series it shows us genuine competition interactions from random variation 

• By comparing the stats of interactions it can determine which interaction (inter/intra) has a stronger effect and to tell what is the stronger competitor

Use a T-score to get a p-value

T-score will help us see how far off the mean weight of the sample (mixed) differs from another sample/ treatment (monoculture) 

P-value tells us probability that the difference in mean biomass or length occurred by chance to reject the null (The average weight of species A is the same in mixtures and in monoculture, no difference exists) and in favor of the alternative (The average weight of species A is significantly different in mixtures than in monoculture) 

Describe what a significant result is and what it tells us

A high T-value = large difference between means of weight or length of seeds in monoculture was mixed 

A low p-value (<0.05) = data is statistically significant to conclude that the difference in means is not due to chance assuming the null to be true 

• Low p-value = data is stat significant in proving that the average weight of species A is significantly different in mixtures than in monoculture

Do species interactions significantly affect growth or mortality? Did you find any negative interactions? Any positive ones?

Species interactions greatly affected plant growth. In the oat mixtures, the average plant weight decreased for surrounding plants compared to monoculture. Indicative of negative interactions (competition) 

• Superior competitor = oat [will do worse in mono, because worse in intraspecifc with it being superior]

• Inferior = Tomato, alfalfa [will do better in mono than mix with oat, because the superior competitor is no longer present]

In the tomato and alfalfa mix, the average plant weight decreased for surrounding alfalfa compared to monoculutre. Indicative of negative interactions (competition) 

• Superior = Tomato, alfalfa [will do better in mono than

Tomato and alfalfa on the other hand showed higher weights in monocultures, suggesting positive interactions or reduced competition