Traits and How They Change Traits and the Environment

1. Traits and How They Change Traits and the Environment

2. What are traits? • Observing Traits • Traits are features organisms inherit. • To improve organisms, they were breed using desired observable traits. • Phenotypes and Genotypes • DNA – coded info of hereditary material in every cell, shaped like twisted ladder • Gene – part of DNA code on a chromosome • Genotype – genetic makeup • Phenotype – observable traits

3. Effects of the Environment • Growth • Trees are in competition for environmental factors in a forest • Compete for light, water, soil minerals • Effects tree population • Appearance • Organism may have same genes, but appearances can be different if not in same environment (water buttercup plant) • Temperatures where an organism lives can change an organisms phenotype (Siamese cat and Arctic Fox)

4. Gender • Some species of fish have ability to change genders (clownfish) • Helps maintain desired male-to-female ratio • Switch back and forth depending on number of males and females in population

5. QuestionsWrite out each question & Answer in Complete Sentences for Full Credit!!! • What are traits? • How were organisms improved? • What is an organism’s genotype? • What is a phenotype? • Which 3 environmental factors effect the population of trees? • How do organisms with the same genes look different? • Why are some species of fish able to change back and forth from male to female?

6. Traits and How They Change Genetics

7. Science of Genetics • What is genetics? • Heredity – passing of traits from parents to offspring • The study of heredity is genetics • Genetics and cell processes explain how species change over time

8. Beginning with Mendel • Dominant and Recessive Traits • Gregor Mendel first to use numbers describing results of genetic experiments • Conclusion – traits are determined by different factors (factors = genes) • Allele – different forms of a gene • Principle of Dominance – when only one form of a trait is shown when both alleles are present. • Dominant Alleles – show effect on phenotype whenever present in genotype. • Recessive Alleles – show effect on phenotype only when 2 of them are present.

9. From Parents to Offspring • Principle of Segregation – each parent passes only one allele for each trait to its offspring. • Explains how offspring can look different from each other • Each sex cell has 3 chromosomes, which can be combined in 8 possible ways • Humans have 46 chromosomes, so 8 million combinations are possible every time sex cells form • Law of Independent Assortment – different traits are inherited with no relation of each other

10. Predicting Genetic Outcomes • Punnett Square • Makes genetic predictions by crossing different organisms with known genotypes • Hybrid – organism with 2 different alleles for a trait • Monohybrid Cross – only one trait, make predictions difficult • Understanding Results • Each result is independent of the ones that came before and after • Probability the prediction is right increases when large numbers are studied

11. Questions – Write ?’s out and Answer in Complete Sentences!!! • What is genetics? • What is the Principle of Dominance? • Which type of allele is shown in the phenotype when two are present? • How is offspring explained when they do not look the same? • How many chromosomes can be found in humans? • What is a Punnett Square? • How can the predictions made by a Punnett Square become more reliable?

12. Traits and How They Change Environmental Impact Over Time

13. Survival and the Environment • Nonliving Influences • Temperature and rainfall • Pollution affect survival • Factors can change species appearances • Fire, height of mountains, volcanic activity, and flooding can be positive or negative factors • Interactions with Other Organisms • Predators • Availability of food • Population of species

14. Species and the Environment • Natural Selection (Charles Darwin) • Evolution – changes that happen over time due to adaptation to the environment. • Natural Selection – organisms that are better adapted to survive and reproduce at a greater rate than another, produces new species. • Mutation • Process where DNA changes result new alleles • Some can be advantageous for survival and reproduction and trait is passed on • Some can keep an organism from surviving and reproducing

15. Selective Breeding • Humans can select different variations to produce many different breeds • Could happen naturally in an environment • Direction of Evolution • Natural Selection can lead to 2 or more new species if more than one variation of a trait is favored • Adaptive Radiation – production of several species from one ancestral species

16. Extinction of Species • Last individual of species dies • Rate of extinction today is as great or greater than the past • Reasons for extinction: • Destruction of habitat • New species • Human impact • Predators • Overcrowding

17. Questions • What nonliving influences affect the survival of species in an environment? • How do other organisms affect the survival of a species? • What is natural selection? • When is a mutated trait passed on to offspring? • What causes the production of several species from one ancestral species? • What are the causes of extinction?